July 2025 - Linux-kselftest-mirror

[PATCH v18 00/27] riscv control-flow integrity for usermode

by Deepak Gupta

Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) In case you're building your own rootfs using toolchain, please make sure you pick following patch to ensure that vDSO compiled with lpad and shadow stack. "arch/riscv: compile vdso with landing pad" Branch where above patch can be picked https://github.com/deepak0414/linux-riscv-cfi/tree/vdso_user_cfi_v6.12-rc1 Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true vDSO related Opens (in the flux) ================================= I am listing these opens for laying out plan and what to expect in future patch sets. And of course for the sake of discussion. Shadow stack and landing pad enabling in vDSO ---------------------------------------------- vDSO must have shadow stack and landing pad support compiled in for task to have shadow stack and landing pad support. This patch series doesn't enable that (yet). Enabling shadow stack support in vDSO should be straight forward (intend to do that in next versions of patch set). Enabling landing pad support in vDSO requires some collaboration with toolchain folks to follow a single label scheme for all object binaries. This is necessary to ensure that all indirect call-sites are setting correct label and target landing pads are decorated with same label scheme. How many vDSOs --------------- Shadow stack instructions are carved out of zimop (may be operations) and if CPU doesn't implement zimop, they're illegal instructions. Kernel could be running on a CPU which may or may not implement zimop. And thus kernel will have to carry 2 different vDSOs and expose the appropriate one depending on whether CPU implements zimop or not. References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ To: Thomas Gleixner <tglx(a)linutronix.de> To: Ingo Molnar <mingo(a)redhat.com> To: Borislav Petkov <bp(a)alien8.de> To: Dave Hansen <dave.hansen(a)linux.intel.com> To: x86(a)kernel.org To: H. Peter Anvin <hpa(a)zytor.com> To: Andrew Morton <akpm(a)linux-foundation.org> To: Liam R. Howlett <Liam.Howlett(a)oracle.com> To: Vlastimil Babka <vbabka(a)suse.cz> To: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> To: Paul Walmsley <paul.walmsley(a)sifive.com> To: Palmer Dabbelt <palmer(a)dabbelt.com> To: Albert Ou <aou(a)eecs.berkeley.edu> To: Conor Dooley <conor(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Arnd Bergmann <arnd(a)arndb.de> To: Christian Brauner <brauner(a)kernel.org> To: Peter Zijlstra <peterz(a)infradead.org> To: Oleg Nesterov <oleg(a)redhat.com> To: Eric Biederman <ebiederm(a)xmission.com> To: Kees Cook <kees(a)kernel.org> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> To: Jann Horn <jannh(a)google.com> To: Conor Dooley <conor+dt(a)kernel.org> To: Miguel Ojeda <ojeda(a)kernel.org> To: Alex Gaynor <alex.gaynor(a)gmail.com> To: Boqun Feng <boqun.feng(a)gmail.com> To: Gary Guo <gary(a)garyguo.net> To: Björn Roy Baron <bjorn3_gh(a)protonmail.com> To: Benno Lossin <benno.lossin(a)proton.me> To: Andreas Hindborg <a.hindborg(a)kernel.org> To: Alice Ryhl <aliceryhl(a)google.com> To: Trevor Gross <tmgross(a)umich.edu> Cc: linux-kernel(a)vger.kernel.org Cc: linux-fsdevel(a)vger.kernel.org Cc: linux-mm(a)kvack.org Cc: linux-riscv(a)lists.infradead.org Cc: devicetree(a)vger.kernel.org Cc: linux-arch(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Cc: alistair.francis(a)wdc.com Cc: richard.henderson(a)linaro.org Cc: jim.shu(a)sifive.com Cc: andybnac(a)gmail.com Cc: kito.cheng(a)sifive.com Cc: charlie(a)rivosinc.com Cc: atishp(a)rivosinc.com Cc: evan(a)rivosinc.com Cc: cleger(a)rivosinc.com Cc: alexghiti(a)rivosinc.com Cc: samitolvanen(a)google.com Cc: broonie(a)kernel.org Cc: rick.p.edgecombe(a)intel.com Cc: rust-for-linux(a)vger.kernel.org changelog --------- v18: - rebased on 6.16-rc1 - uprobe handling clears ELP in sstatus image in pt_regs - vdso was missing shadow stack elf note for object files. added that. Additional asm file for vdso needed the elf marker flag. toolchain should complain if `-fcf-protection=full` and marker is missing for object generated from asm file. Asked toolchain folks to fix this. Although no reason to gate the merge on that. - Split up compile options for march and fcf-protection in vdso Makefile - CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu Added `arch/riscv/configs/hardening.config` fragment which selects CONFIG_RISCV_USER_CFI v17: - fixed warnings due to empty macros in usercfi.h (reported by alexg) - fixed prefixes in commit titles reported by alexg - took below uprobe with fcfi v2 patch from Zong Li and squashed it with "riscv/traps: Introduce software check exception and uprobe handling" https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ v16: - If FWFT is not implemented or returns error for shadow stack activation, then no_usercfi is set to disable shadow stack. Although this should be picked up by extension validation and activation. Fixed this bug for zicfilp and zicfiss both. Thanks to Charlie Jenkins for reporting this. - If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by Charlie Jenkins. - Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to keep it off till we have more hardware availibility with RVA23 profile and zimop/zcmop implemented. Else this will start breaking people's workflow - Includes the fix if "!RV64 and !SBI" then definitions for FWFT in asm-offsets.c error. v15: - Toolchain has been updated to include `-fcf-protection` flag. This exists for x86 as well. Updated kernel patches to compile vDSO and selftest to compile with `fcf-protection=full` flag. - selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. - Patch to enable shadow stack for kernel wasn't hidden behind CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. v14: - rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. - Took Radim's suggestions on bitfields. - Placed cfi_state at the end of thread_info block so that current situation is not disturbed with respect to member fields of thread_info in single cacheline. v13: - cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses riscv_has_extension_unlikely() - uses nops(count) to create nop slide - RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it - changed ternaries to simply use implicit casting to convert to bool. - kernel command line allows to disable zicfilp and zicfiss independently. updated kernel-parameters.txt. - ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace kselftest. - cosmetic and grammatical changes to documentation. v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- Changes in v18: - Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@ri… Changes in v17: - Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@ri… Changes in v16: - Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@ri… Changes in v15: - changelog posted just below cover letter - Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@ri… Changes in v14: - changelog posted just below cover letter - Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@ri… Changes in v13: - changelog posted just below cover letter - Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@ri… Changes in v12: - changelog posted just below cover letter - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - changelog posted just below cover letter - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Deepak Gupta (25): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv/mm: manufacture shadow stack pte riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs riscv/mm: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception and uprobe handling riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: kernel command line option to opt out of user cfi riscv: enable kernel access to shadow stack memory via FWFT sbi call riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad and shadow stack note Documentation/admin-guide/kernel-parameters.txt | 8 + Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 179 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 21 + arch/riscv/Makefile | 5 +- arch/riscv/configs/hardening.config | 4 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 12 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 26 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 95 ++++ arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 34 ++ arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 1 + arch/riscv/kernel/asm-offsets.c | 10 + arch/riscv/kernel/cpufeature.c | 27 + arch/riscv/kernel/entry.S | 33 +- arch/riscv/kernel/head.S | 27 + arch/riscv/kernel/process.c | 27 +- arch/riscv/kernel/ptrace.c | 95 ++++ arch/riscv/kernel/signal.c | 148 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 54 ++ arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ arch/riscv/kernel/vdso/Makefile | 11 +- arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 16 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 2 + include/uapi/linux/prctl.h | 27 + kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 16 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + 56 files changed, 2383 insertions(+), 31 deletions(-) --- base-commit: a2a05801de77ca5122fc34e3eb84d6359ef70389 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - 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[PATCH net-next V2 0/5] selftests: drv-net: Test XDP native support

by Mohsin Bashir

This patch series add tests to validate XDP native support for PASS, DROP, ABORT, and TX actions, as well as headroom and tailroom adjustment. For adjustment tests, validate support for both the extension and shrinking cases across various packet sizes and offset values. The pass criteria for head/tail adjustment tests require that at-least one adjustment value works for at-least one packet size. This ensure that the variability in maximum supported head/tail adjustment offset across different drivers is being incorporated. The results reported in this series are based on fbnic. However, the series is tested against multiple other drivers including netdevism. Note: The XDP support for fbnic will be added later. --- Change-log: V2: - Remove unused and libxdp-devel headers - Fix reverse xmas tree in xdp_native.bpf.c - Reorder headers in xdp_native.bpf.c V1: https://lore.kernel.org/netdev/20250709173707.3177206-1-mohsin.bashr@gmail.… Mohsin Bashir (5): selftests: drv-net: Add bpftool util selftests: drv-net: Test XDP_PASS/DROP support selftests: drv-net: Test XDP_TX support selftests: drv-net: Test tail-adjustment support selftests: drv-net: Test head-adjustment support tools/testing/selftests/drivers/net/Makefile | 1 + .../selftests/drivers/net/lib/py/__init__.py | 2 +- tools/testing/selftests/drivers/net/xdp.py | 663 ++++++++++++++++++ tools/testing/selftests/net/lib/py/utils.py | 4 + .../selftests/net/lib/xdp_native.bpf.c | 524 ++++++++++++++ 5 files changed, 1193 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/drivers/net/xdp.py create mode 100644 tools/testing/selftests/net/lib/xdp_native.bpf.c -- 2.47.1

2 months

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[PATCH] selftests/mm: fix split_huge_page_test for folio_split() tests.

by Zi Yan

PID_FMT does not have an offset field, so folio_split() tests are not performed. Add PID_FMT_OFFSET with an offset field and use it to perform folio_split() tests. Fixes: 80a5c494c89f ("selftests/mm: add tests for folio_split(), buddy allocator like split") Signed-off-by: Zi Yan <ziy(a)nvidia.com> --- tools/testing/selftests/mm/split_huge_page_test.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index aa7400ed0e99..f0d9c035641d 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -31,6 +31,7 @@ uint64_t pmd_pagesize; #define INPUT_MAX 80 #define PID_FMT "%d,0x%lx,0x%lx,%d" +#define PID_FMT_OFFSET "%d,0x%lx,0x%lx,%d,%d" #define PATH_FMT "%s,0x%lx,0x%lx,%d" #define PFN_MASK ((1UL<<55)-1) @@ -483,7 +484,7 @@ void split_thp_in_pagecache_to_order_at(size_t fd_size, const char *fs_loc, write_debugfs(PID_FMT, getpid(), (uint64_t)addr, (uint64_t)addr + fd_size, order); else - write_debugfs(PID_FMT, getpid(), (uint64_t)addr, + write_debugfs(PID_FMT_OFFSET, getpid(), (uint64_t)addr, (uint64_t)addr + fd_size, order, offset); for (i = 0; i < fd_size; i++) -- 2.47.2

2 months

5
5
0 0

[PATCH v2 0/3] module: make structure definitions always visible

by Thomas Weißschuh

Code using IS_ENABLED(CONFIG_MODULES) as a C expression may need access to the module structure definitions to compile. Make sure these structure definitions are always visible. This will conflict with commit 6bb37af62634 ("module: Move modprobe_path and modules_disabled ctl_tables into the module subsys") from the sysctl tree, but the resolution is trivial. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Changes in v2: - Pick up tags from v1 - Keep MODULE_ARCH_INIT and 'struct module' definitions together - Link to v1: https://lore.kernel.org/r/20250612-kunit-ifdef-modules-v1-0-fdccd42dcff8@li… --- Thomas Weißschuh (3): module: move 'struct module_use' to internal.h module: make structure definitions always visible kunit: test: Drop CONFIG_MODULE ifdeffery include/linux/module.h | 29 +++++++++++------------------ kernel/module/internal.h | 7 +++++++ lib/kunit/test.c | 8 -------- 3 files changed, 18 insertions(+), 26 deletions(-) --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20250611-kunit-ifdef-modules-0fefd13ae153 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

2 months

3
6
0 0

[PATCH 0/3] module: make structure definitions always visible

by Thomas Weißschuh

Code using IS_ENABLED(CONFIG_MODULES) as a C expression may need access to the module structure definitions to compile. Make sure these structure definitions are always visible. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> --- Thomas Weißschuh (3): module: move 'struct module_use' to internal.h module: make structure definitions always visible kunit: test: Drop CONFIG_MODULE ifdeffery include/linux/module.h | 30 ++++++++++++------------------ kernel/module/internal.h | 7 +++++++ lib/kunit/test.c | 8 -------- 3 files changed, 19 insertions(+), 26 deletions(-) --- base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494 change-id: 20250611-kunit-ifdef-modules-0fefd13ae153 Best regards, -- Thomas Weißschuh <thomas.weissschuh(a)linutronix.de>

2 months

4
15
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[PATCH net-next v5] ipv6: add `force_forwarding` sysctl to enable per-interface forwarding

by Gabriel Goller

It is currently impossible to enable ipv6 forwarding on a per-interface basis like in ipv4. To enable forwarding on an ipv6 interface we need to enable it on all interfaces and disable it on the other interfaces using a netfilter rule. This is especially cumbersome if you have lots of interface and only want to enable forwarding on a few. According to the sysctl docs [0] the `net.ipv6.conf.all.forwarding` enables forwarding for all interfaces, while the interface-specific `net.ipv6.conf.<interface>.forwarding` configures the interface Host/Router configuration. Introduce a new sysctl flag `force_forwarding`, which can be set on every interface. The ip6_forwarding function will then check if the global forwarding flag OR the force_forwarding flag is active and forward the packet. To preserver backwards-compatibility reset the flag (on all interfaces) to 0 if the net.ipv6.conf.all.forwarding flag is set to 0. Add a short selftest that checks if a packet gets forwarded with and without `force_forwarding`. [0]: https://www.kernel.org/doc/Documentation/networking/ip-sysctl.txt Signed-off-by: Gabriel Goller <g.goller(a)proxmox.com> --- v5: * update conf/all/forwarding docs * simplified backwards-compat comment * remove ASSERT_RTNL as it's guaranteed by __in6_dev_get_rtnl_net() already * cange ip6_forward logic so that it doesn't depend on the idev existing * move WRITE_ONCE inside device lock v4: https://lore.kernel.org/netdev/20250703160154.560239-1-g.goller@proxmox.com/ * actually write the sysctl value to the table * use ASSERT_RTNL() when forwarding the sysctl change * remove useless comments in function body * simplify forwarding and force_forwarding check in ip6_output.c * fix code backticks in Documentation (double instead of single) * add selftests v3: https://lore.kernel.org/netdev/20250702074619.139031-1-g.goller@proxmox.com/ * remove forwarding=0 setting force_forwarding=0 globally. * add min and max (0 and 1) value to sysctl. v2: https://lore.kernel.org/netdev/20250701140423.487411-1-g.goller@proxmox.com/ * rename from `do_forwarding` to `force_forwarding`. * add global `force_forwarding` flag which will enable `force_forwarding` on every interface like the `ipv4.all.forwarding` flag. * `forwarding`=0 will disable global and per-interface `force_forwarding`. * export option as NETCONFA_FORCE_FORWARDING. v1: https://lore.kernel.org/netdev/20250702074619.139031-1-g.goller@proxmox.com/ Documentation/networking/ip-sysctl.rst | 9 +- include/linux/ipv6.h | 1 + include/uapi/linux/ipv6.h | 1 + include/uapi/linux/netconf.h | 1 + include/uapi/linux/sysctl.h | 1 + net/ipv6/addrconf.c | 83 ++++++++++++++ net/ipv6/ip6_output.c | 3 +- tools/testing/selftests/net/Makefile | 1 + .../selftests/net/ipv6_force_forwarding.sh | 105 ++++++++++++++++++ 9 files changed, 202 insertions(+), 3 deletions(-) create mode 100644 tools/testing/selftests/net/ipv6_force_forwarding.sh diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 0f1251cce314..6d92bae0257a 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -2281,8 +2281,8 @@ conf/all/disable_ipv6 - BOOLEAN conf/all/forwarding - BOOLEAN Enable global IPv6 forwarding between all interfaces. - IPv4 and IPv6 work differently here; e.g. netfilter must be used - to control which interfaces may forward packets and which not. + IPv4 and IPv6 work differently here; the ``force_forwarding`` flag must + be used to control which interfaces may forward packets. This also sets all interfaces' Host/Router setting 'forwarding' to the specified value. See below for details. @@ -2292,6 +2292,11 @@ conf/all/forwarding - BOOLEAN proxy_ndp - BOOLEAN Do proxy ndp. +force_forwarding - BOOLEAN + Enable forwarding on this interface only -- regardless of the setting on + ``conf/all/forwarding``. When setting ``conf.all.forwarding`` to 0, + the ``force_forwarding`` flag will be reset on all interfaces. + fwmark_reflect - BOOLEAN Controls the fwmark of kernel-generated IPv6 reply packets that are not associated with a socket for example, TCP RSTs or ICMPv6 echo replies). diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h index 5aeeed22f35b..d975a86f29be 100644 --- a/include/linux/ipv6.h +++ b/include/linux/ipv6.h @@ -17,6 +17,7 @@ struct ipv6_devconf { __s32 hop_limit; __s32 mtu6; __s32 forwarding; + __s32 force_forwarding; __s32 disable_policy; __s32 proxy_ndp; __cacheline_group_end(ipv6_devconf_read_txrx); diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h index cf592d7b630f..d4d3ae774b26 100644 --- a/include/uapi/linux/ipv6.h +++ b/include/uapi/linux/ipv6.h @@ -199,6 +199,7 @@ enum { DEVCONF_NDISC_EVICT_NOCARRIER, DEVCONF_ACCEPT_UNTRACKED_NA, DEVCONF_ACCEPT_RA_MIN_LFT, + DEVCONF_FORCE_FORWARDING, DEVCONF_MAX }; diff --git a/include/uapi/linux/netconf.h b/include/uapi/linux/netconf.h index fac4edd55379..1c8c84d65ae3 100644 --- a/include/uapi/linux/netconf.h +++ b/include/uapi/linux/netconf.h @@ -19,6 +19,7 @@ enum { NETCONFA_IGNORE_ROUTES_WITH_LINKDOWN, NETCONFA_INPUT, NETCONFA_BC_FORWARDING, + NETCONFA_FORCE_FORWARDING, __NETCONFA_MAX }; #define NETCONFA_MAX (__NETCONFA_MAX - 1) diff --git a/include/uapi/linux/sysctl.h b/include/uapi/linux/sysctl.h index 8981f00204db..63d1464cb71c 100644 --- a/include/uapi/linux/sysctl.h +++ b/include/uapi/linux/sysctl.h @@ -573,6 +573,7 @@ enum { NET_IPV6_ACCEPT_RA_FROM_LOCAL=26, NET_IPV6_ACCEPT_RA_RT_INFO_MIN_PLEN=27, NET_IPV6_RA_DEFRTR_METRIC=28, + NET_IPV6_FORCE_FORWARDING=29, __NET_IPV6_MAX }; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index ba2ec7c870cc..92acf44febd1 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -239,6 +239,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = { .ndisc_evict_nocarrier = 1, .ra_honor_pio_life = 0, .ra_honor_pio_pflag = 0, + .force_forwarding = 0, }; static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { @@ -303,6 +304,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = { .ndisc_evict_nocarrier = 1, .ra_honor_pio_life = 0, .ra_honor_pio_pflag = 0, + .force_forwarding = 0, }; /* Check if link is ready: is it up and is a valid qdisc available */ @@ -857,6 +859,9 @@ static void addrconf_forward_change(struct net *net, __s32 newf) idev = __in6_dev_get_rtnl_net(dev); if (idev) { int changed = (!idev->cnf.forwarding) ^ (!newf); + /* Disabling all.forwarding sets 0 to force_forwarding for all interfaces */ + if (newf == 0) + WRITE_ONCE(idev->cnf.force_forwarding, newf); WRITE_ONCE(idev->cnf.forwarding, newf); if (changed) @@ -5719,6 +5724,7 @@ static void ipv6_store_devconf(const struct ipv6_devconf *cnf, array[DEVCONF_ACCEPT_UNTRACKED_NA] = READ_ONCE(cnf->accept_untracked_na); array[DEVCONF_ACCEPT_RA_MIN_LFT] = READ_ONCE(cnf->accept_ra_min_lft); + array[DEVCONF_FORCE_FORWARDING] = READ_ONCE(cnf->force_forwarding); } static inline size_t inet6_ifla6_size(void) @@ -6747,6 +6753,76 @@ static int addrconf_sysctl_disable_policy(const struct ctl_table *ctl, int write return ret; } +static void addrconf_force_forward_change(struct net *net, __s32 newf) +{ + struct net_device *dev; + struct inet6_dev *idev; + + for_each_netdev(net, dev) { + idev = __in6_dev_get_rtnl_net(dev); + if (idev) { + int changed = (!idev->cnf.force_forwarding) ^ (!newf); + + WRITE_ONCE(idev->cnf.force_forwarding, newf); + if (changed) { + inet6_netconf_notify_devconf(dev_net(dev), RTM_NEWNETCONF, + NETCONFA_FORCE_FORWARDING, + dev->ifindex, &idev->cnf); + } + } + } +} + +static int addrconf_sysctl_force_forwarding(const struct ctl_table *ctl, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct inet6_dev *idev = ctl->extra1; + struct ctl_table tmp_ctl = *ctl; + struct net *net = ctl->extra2; + int *valp = ctl->data; + int new_val = *valp; + int old_val = *valp; + loff_t pos = *ppos; + int ret; + + tmp_ctl.extra1 = SYSCTL_ZERO; + tmp_ctl.extra2 = SYSCTL_ONE; + tmp_ctl.data = &new_val; + + ret = proc_douintvec_minmax(&tmp_ctl, write, buffer, lenp, ppos); + + if (write && old_val != new_val) { + if (!rtnl_net_trylock(net)) + return restart_syscall(); + + WRITE_ONCE(*valp, new_val); + + if (valp == &net->ipv6.devconf_dflt->force_forwarding) { + inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_FORCE_FORWARDING, + NETCONFA_IFINDEX_DEFAULT, + net->ipv6.devconf_dflt); + } else if (valp == &net->ipv6.devconf_all->force_forwarding) { + inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_FORCE_FORWARDING, + NETCONFA_IFINDEX_ALL, + net->ipv6.devconf_all); + + addrconf_force_forward_change(net, new_val); + } else { + inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, + NETCONFA_FORCE_FORWARDING, + idev->dev->ifindex, + &idev->cnf); + } + rtnl_net_unlock(net); + } + + if (ret) + *ppos = pos; + return ret; +} + static int minus_one = -1; static const int two_five_five = 255; static u32 ioam6_if_id_max = U16_MAX; @@ -7217,6 +7293,13 @@ static const struct ctl_table addrconf_sysctl[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_TWO, }, + { + .procname = "force_forwarding", + .data = &ipv6_devconf.force_forwarding, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = addrconf_sysctl_force_forwarding, + }, }; static int __addrconf_sysctl_register(struct net *net, char *dev_name, diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 7bd29a9ff0db..3853090d7282 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -509,7 +509,8 @@ int ip6_forward(struct sk_buff *skb) u32 mtu; idev = __in6_dev_get_safely(dev_get_by_index_rcu(net, IP6CB(skb)->iif)); - if (READ_ONCE(net->ipv6.devconf_all->forwarding) == 0) + if (!READ_ONCE(net->ipv6.devconf_all->forwarding) && + (!idev || !READ_ONCE(idev->cnf.force_forwarding))) goto error; if (skb->pkt_type != PACKET_HOST) diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile index 332f387615d7..f64ec8a15a77 100644 --- a/tools/testing/selftests/net/Makefile +++ b/tools/testing/selftests/net/Makefile @@ -112,6 +112,7 @@ TEST_PROGS += skf_net_off.sh TEST_GEN_FILES += skf_net_off TEST_GEN_FILES += tfo TEST_PROGS += tfo_passive.sh +TEST_PROGS += ipv6_force_forwarding.sh # YNL files, must be before "include ..lib.mk" YNL_GEN_FILES := busy_poller netlink-dumps diff --git a/tools/testing/selftests/net/ipv6_force_forwarding.sh b/tools/testing/selftests/net/ipv6_force_forwarding.sh new file mode 100644 index 000000000000..62adc9d4afc9 --- /dev/null +++ b/tools/testing/selftests/net/ipv6_force_forwarding.sh @@ -0,0 +1,105 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Test IPv6 force_forwarding interface property +# +# This test verifies that the force_forwarding property works correctly: +# - When global forwarding is disabled, packets are not forwarded normally +# - When force_forwarding is enabled on an interface, packets are forwarded +# regardless of the global forwarding setting + +source lib.sh + +cleanup() { + cleanup_ns $ns1 $ns2 $ns3 +} + +trap cleanup EXIT + +setup_test() { + # Create three namespaces: sender, router, receiver + setup_ns ns1 ns2 ns3 + + # Create veth pairs: ns1 <-> ns2 <-> ns3 + ip link add name veth12 type veth peer name veth21 + ip link add name veth23 type veth peer name veth32 + + # Move interfaces to namespaces + ip link set veth12 netns $ns1 + ip link set veth21 netns $ns2 + ip link set veth23 netns $ns2 + ip link set veth32 netns $ns3 + + # Configure interfaces + ip -n $ns1 addr add 2001:db8:1::1/64 dev veth12 + ip -n $ns2 addr add 2001:db8:1::2/64 dev veth21 + ip -n $ns2 addr add 2001:db8:2::1/64 dev veth23 + ip -n $ns3 addr add 2001:db8:2::2/64 dev veth32 + + # Bring up interfaces + ip -n $ns1 link set veth12 up + ip -n $ns2 link set veth21 up + ip -n $ns2 link set veth23 up + ip -n $ns3 link set veth32 up + + # Add routes + ip -n $ns1 route add 2001:db8:2::/64 via 2001:db8:1::2 + ip -n $ns3 route add 2001:db8:1::/64 via 2001:db8:2::1 + + # Disable global forwarding + ip netns exec $ns2 sysctl -qw net.ipv6.conf.all.forwarding=0 +} + +test_force_forwarding() { + local ret=0 + + echo "TEST: force_forwarding functionality" + + # Check if force_forwarding sysctl exists + if ! ip netns exec $ns2 test -f /proc/sys/net/ipv6/conf/veth21/force_forwarding; then + echo "SKIP: force_forwarding not available" + return $ksft_skip + fi + + # Test 1: Without force_forwarding, ping should fail + ip netns exec $ns2 sysctl -qw net.ipv6.conf.veth21.force_forwarding=0 + ip netns exec $ns2 sysctl -qw net.ipv6.conf.veth23.force_forwarding=0 + + if ip netns exec $ns1 ping -6 -c 1 -W 2 2001:db8:2::2 &>/dev/null; then + echo "FAIL: ping succeeded when forwarding disabled" + ret=1 + else + echo "PASS: forwarding disabled correctly" + fi + + # Test 2: With force_forwarding enabled, ping should succeed + ip netns exec $ns2 sysctl -qw net.ipv6.conf.veth21.force_forwarding=1 + ip netns exec $ns2 sysctl -qw net.ipv6.conf.veth23.force_forwarding=1 + + if ip netns exec $ns1 ping -6 -c 1 -W 2 2001:db8:2::2 &>/dev/null; then + echo "PASS: force_forwarding enabled forwarding" + else + echo "FAIL: ping failed with force_forwarding enabled" + ret=1 + fi + + return $ret +} + +echo "IPv6 force_forwarding test" +echo "==========================" + +setup_test +test_force_forwarding +ret=$? + +if [ $ret -eq 0 ]; then + echo "OK" + exit 0 +elif [ $ret -eq $ksft_skip ]; then + echo "SKIP" + exit $ksft_skip +else + echo "FAIL" + exit 1 +fi -- 2.39.5

2 months

3
3
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[PATCH v4] selftests/mm: add process_madvise() tests

by wang lian

Add tests for process_madvise(), focusing on verifying behavior under various conditions including valid usage and error cases. Signed-off-by: wang lian <lianux.mm(a)gmail.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Suggested-by: David Hildenbrand <david(a)redhat.com> Suggested-by: Zi Yan <ziy(a)nvidia.com> Acked-by: SeongJae Park <sj(a)kernel.org> --- Changelog v4: - Refine resource cleanup logic in test teardown to be more robust. - Improve remote_collapse test to correctly handle different THP (Transparent Huge Page) policies ('always', 'madvise', 'never'), including handling race conditions with khugepaged. - Resolve build errors Changelog v3: https://lore.kernel.org/lkml/20250703044326.65061-1-lianux.mm@gmail.com/ - Rebased onto the latest mm-stable branch to ensure clean application. - Refactor common signal handling logic into vm_util to reduce code duplication. - Improve test robustness and diagnostics based on community feedback. - Address minor code style and script corrections. Changelog v2: https://lore.kernel.org/lkml/20250630140957.4000-1-lianux.mm@gmail.com/ - Drop MADV_DONTNEED tests based on feedback. - Focus solely on process_madvise() syscall. - Improve error handling and structure. - Add future-proof flag test. - Style and comment cleanups. -V1: https://lore.kernel.org/lkml/20250621133003.4733-1-lianux.mm@gmail.com/ tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/guard-regions.c | 51 --- tools/testing/selftests/mm/process_madv.c | 447 +++++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 5 + tools/testing/selftests/mm/vm_util.c | 35 ++ tools/testing/selftests/mm/vm_util.h | 22 + 7 files changed, 511 insertions(+), 51 deletions(-) create mode 100644 tools/testing/selftests/mm/process_madv.c diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 824266982aa3..95bd9c6ead9e 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -25,6 +25,7 @@ pfnmap protection_keys protection_keys_32 protection_keys_64 +process_madv madv_populate uffd-stress uffd-unit-tests diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index ae6f994d3add..d13b3cef2a2b 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -85,6 +85,7 @@ TEST_GEN_FILES += mseal_test TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += pagemap_ioctl TEST_GEN_FILES += pfnmap +TEST_GEN_FILES += process_madv TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += uffd-stress diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c index 93af3d3760f9..4cf101b0fe5e 100644 --- a/tools/testing/selftests/mm/guard-regions.c +++ b/tools/testing/selftests/mm/guard-regions.c @@ -9,8 +9,6 @@ #include <linux/limits.h> #include <linux/userfaultfd.h> #include <linux/fs.h> -#include <setjmp.h> -#include <signal.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> @@ -24,24 +22,6 @@ #include "../pidfd/pidfd.h" -/* - * Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1: - * - * "If the signal occurs other than as the result of calling the abort or raise - * function, the behavior is undefined if the signal handler refers to any - * object with static storage duration other than by assigning a value to an - * object declared as volatile sig_atomic_t" - */ -static volatile sig_atomic_t signal_jump_set; -static sigjmp_buf signal_jmp_buf; - -/* - * Ignore the checkpatch warning, we must read from x but don't want to do - * anything with it in order to trigger a read page fault. We therefore must use - * volatile to stop the compiler from optimising this away. - */ -#define FORCE_READ(x) (*(volatile typeof(x) *)x) - /* * How is the test backing the mapping being tested? */ @@ -120,14 +100,6 @@ static int userfaultfd(int flags) return syscall(SYS_userfaultfd, flags); } -static void handle_fatal(int c) -{ - if (!signal_jump_set) - return; - - siglongjmp(signal_jmp_buf, c); -} - static ssize_t sys_process_madvise(int pidfd, const struct iovec *iovec, size_t n, int advice, unsigned int flags) { @@ -180,29 +152,6 @@ static bool try_read_write_buf(char *ptr) return try_read_buf(ptr) && try_write_buf(ptr); } -static void setup_sighandler(void) -{ - struct sigaction act = { - .sa_handler = &handle_fatal, - .sa_flags = SA_NODEFER, - }; - - sigemptyset(&act.sa_mask); - if (sigaction(SIGSEGV, &act, NULL)) - ksft_exit_fail_perror("sigaction"); -} - -static void teardown_sighandler(void) -{ - struct sigaction act = { - .sa_handler = SIG_DFL, - .sa_flags = SA_NODEFER, - }; - - sigemptyset(&act.sa_mask); - sigaction(SIGSEGV, &act, NULL); -} - static int open_file(const char *prefix, char *path) { int fd; diff --git a/tools/testing/selftests/mm/process_madv.c b/tools/testing/selftests/mm/process_madv.c new file mode 100644 index 000000000000..7d7509486d46 --- /dev/null +++ b/tools/testing/selftests/mm/process_madv.c @@ -0,0 +1,447 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#define _GNU_SOURCE +#include "../kselftest_harness.h" +#include <errno.h> +#include <setjmp.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <linux/mman.h> +#include <sys/syscall.h> +#include <unistd.h> +#include <sched.h> +#include <linux/pidfd.h> +#include <linux/uio.h> +#include "vm_util.h" + +FIXTURE(process_madvise) +{ + int pidfd; + int flag; + pid_t child_pid; +}; + +FIXTURE_SETUP(process_madvise) +{ + self->pidfd = PIDFD_SELF; + self->flag = 0; + self->child_pid = -1; + setup_sighandler(); +}; + +FIXTURE_TEARDOWN_PARENT(process_madvise) +{ + teardown_sighandler(); + if (self->child_pid > 0) { + kill(self->child_pid, SIGKILL); + waitpid(self->child_pid, NULL, 0); + } +} + +static ssize_t sys_process_madvise(int pidfd, const struct iovec *iovec, + size_t vlen, int advice, unsigned int flags) +{ + return syscall(__NR_process_madvise, pidfd, iovec, vlen, advice, flags); +} + +/* + * Enable our signal catcher and try to read the specified buffer. The + * return value indicates whether the read succeeds without a fatal + * signal. + */ +static bool try_read_buf(char *ptr) +{ + bool failed; + + /* Tell signal handler to jump back here on fatal signal. */ + signal_jump_set = true; + /* If a fatal signal arose, we will jump back here and failed is set. */ + failed = sigsetjmp(signal_jmp_buf, 0) != 0; + + if (!failed) + FORCE_READ(ptr); + + signal_jump_set = false; + return !failed; +} + +TEST_F(process_madvise, basic) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + const int madvise_pages = 4; + char *map; + ssize_t ret; + struct iovec vec[madvise_pages]; + + /* + * Create a single large mapping. We will pick pages from this + * mapping to advise on. This ensures we test non-contiguous iovecs. + */ + map = mmap(NULL, pagesize * 10, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (map == MAP_FAILED) + ksft_exit_skip("mmap failed, not enough memory.\n"); + + /* Fill the entire region with a known pattern. */ + memset(map, 'A', pagesize * 10); + + /* + * Setup the iovec to point to 4 non-contiguous pages + * within the mapping. + */ + vec[0].iov_base = &map[0 * pagesize]; + vec[0].iov_len = pagesize; + vec[1].iov_base = &map[3 * pagesize]; + vec[1].iov_len = pagesize; + vec[2].iov_base = &map[5 * pagesize]; + vec[2].iov_len = pagesize; + vec[3].iov_base = &map[8 * pagesize]; + vec[3].iov_len = pagesize; + + ret = sys_process_madvise(PIDFD_SELF, vec, madvise_pages, MADV_DONTNEED, + 0); + if (ret == -1 && errno == EPERM) + ksft_exit_skip( + "process_madvise() unsupported or permission denied, try running as root.\n"); + else if (errno == EINVAL) + ksft_exit_skip( + "process_madvise() unsupported or parameter invalid, please check arguments.\n"); + + /* The call should succeed and report the total bytes processed. */ + ASSERT_EQ(ret, madvise_pages * pagesize); + + /* Check that advised pages are now zero. */ + for (int i = 0; i < madvise_pages; i++) { + char *advised_page = (char *)vec[i].iov_base; + + /* Access should be successful (kernel provides a new page). */ + ASSERT_TRUE(try_read_buf(advised_page)); + /* Content must be 0, not 'A'. */ + ASSERT_EQ(*advised_page, 0); + } + + /* Check that an un-advised page in between is still 'A'. */ + char *unadvised_page = &map[1 * pagesize]; + + ASSERT_TRUE(try_read_buf(unadvised_page)); + for (int i = 0; i < pagesize; i++) + ASSERT_EQ(unadvised_page[i], 'A'); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize * 10), 0); +} + +static long get_smaps_anon_huge_pages(pid_t pid, void *addr) +{ + char smaps_path[64]; + char *line = NULL; + unsigned long start, end; + long anon_huge_kb; + size_t len; + FILE *f; + bool in_vma; + + in_vma = false; + snprintf(smaps_path, sizeof(smaps_path), "/proc/%d/smaps", pid); + f = fopen(smaps_path, "r"); + if (!f) + return -1; + + while (getline(&line, &len, f) != -1) { + /* Check if the line describes a VMA range */ + if (sscanf(line, "%lx-%lx", &start, &end) == 2) { + if ((unsigned long)addr >= start && + (unsigned long)addr < end) + in_vma = true; + else + in_vma = false; + continue; + } + + /* If we are in the correct VMA, look for the AnonHugePages field */ + if (in_vma && + sscanf(line, "AnonHugePages: %ld kB", &anon_huge_kb) == 1) + break; + } + + free(line); + fclose(f); + + return (anon_huge_kb > 0) ? (anon_huge_kb * 1024) : 0; +} + +static bool is_thp_always(void) +{ + const char *path = "/sys/kernel/mm/transparent_hugepage/enabled"; + char buf[32]; + FILE *f = fopen(path, "r"); + + if (!f) + return false; + + if (fgets(buf, sizeof(buf), f)) + if (strstr(buf, "[always]")) { + fclose(f); + return true; + } + + fclose(f); + return false; +} + +/** + * TEST_F(process_madvise, remote_collapse) + * + * This test deterministically validates process_madvise() with MADV_COLLAPSE + * on a remote process, other advices are difficult to verify reliably. + * + * The test verifies that a memory region in a child process, initially + * backed by small pages, can be collapsed into a Transparent Huge Page by a + * request from the parent. The result is verified by parsing the child's + * /proc/<pid>/smaps file. + */ +TEST_F(process_madvise, remote_collapse) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + int pidfd; + long huge_page_size; + int pipe_info[2]; + ssize_t ret; + struct iovec vec; + + struct child_info { + pid_t pid; + void *map_addr; + } info; + + huge_page_size = default_huge_page_size(); + if (huge_page_size <= 0) + ksft_exit_skip("Could not determine a valid huge page size.\n"); + + ASSERT_EQ(pipe(pipe_info), 0); + + self->child_pid = fork(); + ASSERT_NE(self->child_pid, -1); + + if (self->child_pid == 0) { + char *map; + size_t map_size = 2 * huge_page_size; + + close(pipe_info[0]); + + map = mmap(NULL, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Fault in as small pages */ + for (size_t i = 0; i < map_size; i += pagesize) + map[i] = 'A'; + + /* Send info and pause */ + info.pid = getpid(); + info.map_addr = map; + ret = write(pipe_info[1], &info, sizeof(info)); + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[1]); + + pause(); + exit(0); + } + + close(pipe_info[1]); + + /* Receive child info */ + ret = read(pipe_info[0], &info, sizeof(info)); + if (ret <= 0) { + waitpid(self->child_pid, NULL, 0); + ksft_exit_skip("Failed to read child info from pipe.\n"); + } + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[0]); + self->child_pid = info.pid; + + pidfd = syscall(__NR_pidfd_open, self->child_pid, 0); + ASSERT_GE(pidfd, 0); + + vec.iov_base = info.map_addr; + vec.iov_len = huge_page_size; + + if (is_thp_always()) { + long initial_huge_pages; + + /* + * When THP is 'always', khugepaged may pre-emptively + * collapse the pages before our MADV_COLLAPSE call. Check + * the initial state to provide a more accurate test report. + */ + initial_huge_pages = + get_smaps_anon_huge_pages(self->child_pid, info.map_addr); + + if (initial_huge_pages == 2 * huge_page_size) { + /* + * The pages were already collapsed by khugepaged. + * The test goal narrows to verifying that MADV_COLLAPSE + * correctly returns success on an already-collapsed + * region, as documented. + */ + ksft_test_result_skip( + "THP is 'always' and pages were pre-collapsed; verifying success on already-collapsed page.\n"); + + ret = sys_process_madvise(pidfd, &vec, 1, MADV_COLLAPSE, + 0); + ASSERT_EQ(ret, huge_page_size); + goto cleanup; + } + + /* + * Pages are still small, creating a race between our call + * and khugepaged. This is the main test scenario for 'always'. + */ + ret = sys_process_madvise(pidfd, &vec, 1, MADV_COLLAPSE, 0); + + if (ret == -1) { + /* + * MADV_COLLAPSE lost the race to khugepaged, which + * likely held a page lock. The kernel correctly + * reports this temporary contention with EAGAIN. + */ + if (errno == EAGAIN) { + ksft_test_result_skip( + "THP is 'always', process_madvise returned EAGAIN due to an expected race with khugepaged.\n"); + } else { + ksft_test_result_fail( + "process_madvise failed with unexpected errno %d in 'always' mode.\n", + errno); + } + goto cleanup; + } + + /* + * MADV_COLLAPSE won the race and successfully collapsed + * the pages. Verify the final state. + */ + ASSERT_EQ(ret, huge_page_size); + ASSERT_EQ(get_smaps_anon_huge_pages(self->child_pid, info.map_addr), + huge_page_size); + ksft_test_result_pass( + "THP is 'always', MADV_COLLAPSE won race and collapsed pages.\n"); + goto cleanup; + } + + /* + * THP is 'madvise' or 'never'. No race is expected with khugepaged. + * We can perform a straightforward state-change verification. + */ + ASSERT_EQ(get_smaps_anon_huge_pages(self->child_pid, info.map_addr), 0); + + ret = sys_process_madvise(pidfd, &vec, 1, MADV_COLLAPSE, 0); + if (ret == -1) { + if (errno == EINVAL) + ksft_exit_skip( + "PROCESS_MADV_ADVISE is not supported.\n"); + else if (errno == EPERM) + ksft_exit_skip( + "No process_madvise() permissions, try running as root.\n"); + goto cleanup; + } + ASSERT_EQ(ret, huge_page_size); + + ASSERT_EQ(get_smaps_anon_huge_pages(self->child_pid, info.map_addr), + huge_page_size); + + ksft_test_result_pass( + "MADV_COLLAPSE successfully verified via smaps.\n"); + +cleanup: + /* Cleanup */ + kill(self->child_pid, SIGKILL); + waitpid(self->child_pid, NULL, 0); + if (pidfd >= 0) + close(pidfd); +} + +/* + * Test process_madvise() with various invalid pidfds to ensure correct error + * handling. This includes negative fds, non-pidfd fds, and pidfds for + * processes that no longer exist. + */ +TEST_F(process_madvise, invalid_pidfd) +{ + struct iovec vec; + pid_t child_pid; + ssize_t ret; + int pidfd; + + vec.iov_base = (void *)0x1234; + vec.iov_len = 4096; + + /* Using an invalid fd number (-1) should fail with EBADF. */ + ret = sys_process_madvise(-1, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a valid fd that is not a pidfd (e.g. stdin) should fail + * with EBADF. + */ + ret = sys_process_madvise(STDIN_FILENO, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a pidfd for a process that has already exited should fail + * with ESRCH. + */ + child_pid = fork(); + ASSERT_NE(child_pid, -1); + + if (child_pid == 0) + exit(0); + + pidfd = syscall(__NR_pidfd_open, child_pid, 0); + ASSERT_GE(pidfd, 0); + + /* Wait for the child to ensure it has terminated. */ + waitpid(child_pid, NULL, 0); + + ret = sys_process_madvise(pidfd, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ESRCH); + close(pidfd); +} + +/* + * Test process_madvise() with an invalid flag value. Now we only support flag=0 + * future we will use it support sync so reserve this test. + */ +TEST_F(process_madvise, flag) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + unsigned int invalid_flag; + struct iovec vec; + char *map; + ssize_t ret; + + map = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, + 0); + if (map == MAP_FAILED) + ksft_exit_skip("mmap failed, not enough memory.\n"); + + vec.iov_base = map; + vec.iov_len = pagesize; + + invalid_flag = 0x80000000; + + ret = sys_process_madvise(PIDFD_SELF, &vec, 1, MADV_DONTNEED, + invalid_flag); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize), 0); +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index dddd1dd8af14..84fb51902c3e 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -65,6 +65,8 @@ separated by spaces: test pagemap_scan IOCTL - pfnmap tests for VM_PFNMAP handling +- process_madv + test process_madvise - cow test copy-on-write semantics - thp @@ -422,6 +424,9 @@ CATEGORY="hmm" run_test bash ./test_hmm.sh smoke # MADV_GUARD_INSTALL and MADV_GUARD_REMOVE tests CATEGORY="madv_guard" run_test ./guard-regions +# PROCESS_MADVISE TEST +CATEGORY="process_madv" run_test ./process_madv + # MADV_POPULATE_READ and MADV_POPULATE_WRITE tests CATEGORY="madv_populate" run_test ./madv_populate diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 5492e3f784df..85b209260e5a 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -20,6 +20,9 @@ unsigned int __page_size; unsigned int __page_shift; +volatile sig_atomic_t signal_jump_set; +sigjmp_buf signal_jmp_buf; + uint64_t pagemap_get_entry(int fd, char *start) { const unsigned long pfn = (unsigned long)start / getpagesize(); @@ -524,3 +527,35 @@ int read_sysfs(const char *file_path, unsigned long *val) return 0; } + +static void handle_fatal(int c) +{ + if (!signal_jump_set) + return; + + siglongjmp(signal_jmp_buf, c); +} + +void setup_sighandler(void) +{ + struct sigaction act = { + .sa_handler = &handle_fatal, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + if (sigaction(SIGSEGV, &act, NULL)) + ksft_exit_fail_perror("sigaction in setup"); +} + +void teardown_sighandler(void) +{ + struct sigaction act = { + .sa_handler = SIG_DFL, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + if (sigaction(SIGSEGV, &act, NULL)) + ksft_exit_fail_perror("sigaction in teardown"); +} diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index b8136d12a0f8..6bc4177a2807 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -8,6 +8,8 @@ #include <unistd.h> /* _SC_PAGESIZE */ #include "../kselftest.h" #include <linux/fs.h> +#include <setjmp.h> +#include <signal.h> #define BIT_ULL(nr) (1ULL << (nr)) #define PM_SOFT_DIRTY BIT_ULL(55) @@ -61,6 +63,24 @@ static inline void skip_test_dodgy_fs(const char *op_name) ksft_test_result_skip("%s failed with ENOENT. Filesystem might be buggy (9pfs?)\n", op_name); } +/* + * Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1: + * + * "If the signal occurs other than as the result of calling the abort or raise + * function, the behavior is undefined if the signal handler refers to any + * object with static storage duration other than by assigning a value to an + * object declared as volatile sig_atomic_t" + */ +extern volatile sig_atomic_t signal_jump_set; +extern sigjmp_buf signal_jmp_buf; + +/* + * Ignore the checkpatch warning, we must read from x but don't want to do + * anything with it in order to trigger a read page fault. We therefore must use + * volatile to stop the compiler from optimising this away. + */ +#define FORCE_READ(x) (*(volatile typeof(x) *)x) + uint64_t pagemap_get_entry(int fd, char *start); bool pagemap_is_softdirty(int fd, char *start); bool pagemap_is_swapped(int fd, char *start); @@ -90,6 +110,8 @@ bool find_vma_procmap(struct procmap_fd *procmap, void *address); int close_procmap(struct procmap_fd *procmap); int write_sysfs(const char *file_path, unsigned long val); int read_sysfs(const char *file_path, unsigned long *val); +void setup_sighandler(void); +void teardown_sighandler(void); static inline int open_self_procmap(struct procmap_fd *procmap_out) { -- 2.43.0

2 months

4
11
0 0

[PATCH v3] selftests/mm: add process_madvise() tests

by wang lian

Add tests for process_madvise(), focusing on verifying behavior under various conditions including valid usage and error cases. Signed-off-by: wang lian <lianux.mm(a)gmail.com> Suggested-by: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> Suggested-by: David Hildenbrand <david(a)redhat.com> Acked-by: SeongJae Park <sj(a)kernel.org> --- Changelog v3: - Rebased onto the latest mm-stable branch to ensure clean application. - Refactor common signal handling logic into vm_util to reduce code duplication. - Improve test robustness and diagnostics based on community feedback. - Address minor code style and script corrections. Changelog v2: - Drop MADV_DONTNEED tests based on feedback. - Focus solely on process_madvise() syscall. - Improve error handling and structure. - Add future-proof flag test. - Style and comment cleanups. tools/testing/selftests/mm/.gitignore | 1 + tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/guard-regions.c | 51 --- tools/testing/selftests/mm/process_madv.c | 358 +++++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 5 + tools/testing/selftests/mm/vm_util.c | 35 ++ tools/testing/selftests/mm/vm_util.h | 22 ++ 7 files changed, 422 insertions(+), 51 deletions(-) create mode 100644 tools/testing/selftests/mm/process_madv.c diff --git a/tools/testing/selftests/mm/.gitignore b/tools/testing/selftests/mm/.gitignore index 824266982aa3..95bd9c6ead9e 100644 --- a/tools/testing/selftests/mm/.gitignore +++ b/tools/testing/selftests/mm/.gitignore @@ -25,6 +25,7 @@ pfnmap protection_keys protection_keys_32 protection_keys_64 +process_madv madv_populate uffd-stress uffd-unit-tests diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index ae6f994d3add..d13b3cef2a2b 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -85,6 +85,7 @@ TEST_GEN_FILES += mseal_test TEST_GEN_FILES += on-fault-limit TEST_GEN_FILES += pagemap_ioctl TEST_GEN_FILES += pfnmap +TEST_GEN_FILES += process_madv TEST_GEN_FILES += thuge-gen TEST_GEN_FILES += transhuge-stress TEST_GEN_FILES += uffd-stress diff --git a/tools/testing/selftests/mm/guard-regions.c b/tools/testing/selftests/mm/guard-regions.c index 93af3d3760f9..4cf101b0fe5e 100644 --- a/tools/testing/selftests/mm/guard-regions.c +++ b/tools/testing/selftests/mm/guard-regions.c @@ -9,8 +9,6 @@ #include <linux/limits.h> #include <linux/userfaultfd.h> #include <linux/fs.h> -#include <setjmp.h> -#include <signal.h> #include <stdbool.h> #include <stdio.h> #include <stdlib.h> @@ -24,24 +22,6 @@ #include "../pidfd/pidfd.h" -/* - * Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1: - * - * "If the signal occurs other than as the result of calling the abort or raise - * function, the behavior is undefined if the signal handler refers to any - * object with static storage duration other than by assigning a value to an - * object declared as volatile sig_atomic_t" - */ -static volatile sig_atomic_t signal_jump_set; -static sigjmp_buf signal_jmp_buf; - -/* - * Ignore the checkpatch warning, we must read from x but don't want to do - * anything with it in order to trigger a read page fault. We therefore must use - * volatile to stop the compiler from optimising this away. - */ -#define FORCE_READ(x) (*(volatile typeof(x) *)x) - /* * How is the test backing the mapping being tested? */ @@ -120,14 +100,6 @@ static int userfaultfd(int flags) return syscall(SYS_userfaultfd, flags); } -static void handle_fatal(int c) -{ - if (!signal_jump_set) - return; - - siglongjmp(signal_jmp_buf, c); -} - static ssize_t sys_process_madvise(int pidfd, const struct iovec *iovec, size_t n, int advice, unsigned int flags) { @@ -180,29 +152,6 @@ static bool try_read_write_buf(char *ptr) return try_read_buf(ptr) && try_write_buf(ptr); } -static void setup_sighandler(void) -{ - struct sigaction act = { - .sa_handler = &handle_fatal, - .sa_flags = SA_NODEFER, - }; - - sigemptyset(&act.sa_mask); - if (sigaction(SIGSEGV, &act, NULL)) - ksft_exit_fail_perror("sigaction"); -} - -static void teardown_sighandler(void) -{ - struct sigaction act = { - .sa_handler = SIG_DFL, - .sa_flags = SA_NODEFER, - }; - - sigemptyset(&act.sa_mask); - sigaction(SIGSEGV, &act, NULL); -} - static int open_file(const char *prefix, char *path) { int fd; diff --git a/tools/testing/selftests/mm/process_madv.c b/tools/testing/selftests/mm/process_madv.c new file mode 100644 index 000000000000..3d26105b4781 --- /dev/null +++ b/tools/testing/selftests/mm/process_madv.c @@ -0,0 +1,358 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#define _GNU_SOURCE +#include "../kselftest_harness.h" +#include <errno.h> +#include <setjmp.h> +#include <signal.h> +#include <stdbool.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/mman.h> +#include <sys/syscall.h> +#include <unistd.h> +#include <sched.h> +#include <sys/pidfd.h> +#include "vm_util.h" + +#include "../pidfd/pidfd.h" + +FIXTURE(process_madvise) +{ + int pidfd; + int flag; +}; + +FIXTURE_SETUP(process_madvise) +{ + self->pidfd = PIDFD_SELF; + self->flag = 0; + setup_sighandler(); +}; + +FIXTURE_TEARDOWN(process_madvise) +{ + teardown_sighandler(); +} + +static ssize_t sys_process_madvise(int pidfd, const struct iovec *iovec, + size_t vlen, int advice, unsigned int flags) +{ + return syscall(__NR_process_madvise, pidfd, iovec, vlen, advice, flags); +} + +/* + * Enable our signal catcher and try to read the specified buffer. The + * return value indicates whether the read succeeds without a fatal + * signal. + */ +static bool try_read_buf(char *ptr) +{ + bool failed; + + /* Tell signal handler to jump back here on fatal signal. */ + signal_jump_set = true; + /* If a fatal signal arose, we will jump back here and failed is set. */ + failed = sigsetjmp(signal_jmp_buf, 0) != 0; + + if (!failed) + FORCE_READ(ptr); + + signal_jump_set = false; + return !failed; +} + +TEST_F(process_madvise, basic) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + const int madvise_pages = 4; + char *map; + ssize_t ret; + struct iovec vec[madvise_pages]; + + /* + * Create a single large mapping. We will pick pages from this + * mapping to advise on. This ensures we test non-contiguous iovecs. + */ + map = mmap(NULL, pagesize * 10, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + if (map == MAP_FAILED) + ksft_exit_skip("mmap failed, not enough memory.\n"); + + /* Fill the entire region with a known pattern. */ + memset(map, 'A', pagesize * 10); + + /* + * Setup the iovec to point to 4 non-contiguous pages + * within the mapping. + */ + vec[0].iov_base = &map[0 * pagesize]; + vec[0].iov_len = pagesize; + vec[1].iov_base = &map[3 * pagesize]; + vec[1].iov_len = pagesize; + vec[2].iov_base = &map[5 * pagesize]; + vec[2].iov_len = pagesize; + vec[3].iov_base = &map[8 * pagesize]; + vec[3].iov_len = pagesize; + + ret = sys_process_madvise(PIDFD_SELF, vec, madvise_pages, MADV_DONTNEED, + 0); + if (ret == -1 && errno == EPERM) + ksft_exit_skip( + "process_madvise() unsupported or permission denied, try running as root.\n"); + else if (errno == EINVAL) + ksft_exit_skip( + "process_madvise() unsupported or parameter invalid, please check arguments.\n"); + + /* The call should succeed and report the total bytes processed. */ + ASSERT_EQ(ret, madvise_pages * pagesize); + + /* Check that advised pages are now zero. */ + for (int i = 0; i < madvise_pages; i++) { + char *advised_page = (char *)vec[i].iov_base; + + /* Access should be successful (kernel provides a new page). */ + ASSERT_TRUE(try_read_buf(advised_page)); + /* Content must be 0, not 'A'. */ + ASSERT_EQ(*advised_page, 0); + } + + /* Check that an un-advised page in between is still 'A'. */ + char *unadvised_page = &map[1 * pagesize]; + + ASSERT_TRUE(try_read_buf(unadvised_page)); + for (int i = 0; i < pagesize; i++) + ASSERT_EQ(unadvised_page[i], 'A'); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize * 10), 0); +} + +static long get_smaps_anon_huge_pages(pid_t pid, void *addr) +{ + char smaps_path[64]; + char *line = NULL; + unsigned long start, end; + long anon_huge_kb; + size_t len; + FILE *f; + bool in_vma; + + in_vma = false; + snprintf(smaps_path, sizeof(smaps_path), "/proc/%d/smaps", pid); + f = fopen(smaps_path, "r"); + if (!f) + return -1; + + while (getline(&line, &len, f) != -1) { + /* Check if the line describes a VMA range */ + if (sscanf(line, "%lx-%lx", &start, &end) == 2) { + if ((unsigned long)addr >= start && + (unsigned long)addr < end) + in_vma = true; + else + in_vma = false; + continue; + } + + /* If we are in the correct VMA, look for the AnonHugePages field */ + if (in_vma && + sscanf(line, "AnonHugePages: %ld kB", &anon_huge_kb) == 1) + break; + } + + free(line); + fclose(f); + + return (anon_huge_kb > 0) ? (anon_huge_kb * 1024) : 0; +} + +/** + * TEST_F(process_madvise, remote_collapse) + * + * This test deterministically validates process_madvise() with MADV_COLLAPSE + * on a remote process, other advices are difficult to verify reliably. + * + * The test verifies that a memory region in a child process, initially + * backed by small pages, can be collapsed into a Transparent Huge Page by a + * request from the parent. The result is verified by parsing the child's + * /proc/<pid>/smaps file. + */ +TEST_F(process_madvise, remote_collapse) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + pid_t child_pid; + int pidfd; + long huge_page_size; + int pipe_info[2]; + ssize_t ret; + struct iovec vec; + + struct child_info { + pid_t pid; + void *map_addr; + } info; + + huge_page_size = default_huge_page_size(); + if (huge_page_size <= 0) + ksft_exit_skip("Could not determine a valid huge page size.\n"); + + ASSERT_EQ(pipe(pipe_info), 0); + + child_pid = fork(); + ASSERT_NE(child_pid, -1); + + if (child_pid == 0) { + char *map; + size_t map_size = 2 * huge_page_size; + + close(pipe_info[0]); + + map = mmap(NULL, map_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(map, MAP_FAILED); + + /* Fault in as small pages */ + for (size_t i = 0; i < map_size; i += pagesize) + map[i] = 'A'; + + /* Send info and pause */ + info.pid = getpid(); + info.map_addr = map; + ret = write(pipe_info[1], &info, sizeof(info)); + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[1]); + + pause(); + exit(0); + } + + close(pipe_info[1]); + + /* Receive child info */ + ret = read(pipe_info[0], &info, sizeof(info)); + if (ret <= 0) { + waitpid(child_pid, NULL, 0); + ksft_exit_skip("Failed to read child info from pipe.\n"); + } + ASSERT_EQ(ret, sizeof(info)); + close(pipe_info[0]); + child_pid = info.pid; + + pidfd = pidfd_open(child_pid, 0); + ASSERT_GE(pidfd, 0); + + /* Baseline Check from Parent's perspective */ + ASSERT_EQ(get_smaps_anon_huge_pages(child_pid, info.map_addr), 0); + + vec.iov_base = info.map_addr; + vec.iov_len = huge_page_size; + ret = sys_process_madvise(pidfd, &vec, 1, MADV_COLLAPSE, 0); + if (ret == -1) { + if (errno == EINVAL) + ksft_exit_skip( + "PROCESS_MADV_ADVISE is not supported.\n"); + else if (errno == EPERM) + ksft_exit_skip( + "No process_madvise() permissions, try running as root.\n"); + goto cleanup; + } + ASSERT_EQ(ret, huge_page_size); + + ASSERT_EQ(get_smaps_anon_huge_pages(child_pid, info.map_addr), + huge_page_size); + + ksft_test_result_pass( + "MADV_COLLAPSE successfully verified via smaps.\n"); + +cleanup: + /* Cleanup */ + kill(child_pid, SIGKILL); + waitpid(child_pid, NULL, 0); + if (pidfd >= 0) + close(pidfd); +} + +/* + * Test process_madvise() with various invalid pidfds to ensure correct error + * handling. This includes negative fds, non-pidfd fds, and pidfds for + * processes that no longer exist. + */ +TEST_F(process_madvise, invalid_pidfd) +{ + struct iovec vec; + pid_t child_pid; + ssize_t ret; + int pidfd; + + vec.iov_base = (void *)0x1234; + vec.iov_len = 4096; + + /* Using an invalid fd number (-1) should fail with EBADF. */ + ret = sys_process_madvise(-1, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a valid fd that is not a pidfd (e.g. stdin) should fail + * with EBADF. + */ + ret = sys_process_madvise(STDIN_FILENO, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EBADF); + + /* + * Using a pidfd for a process that has already exited should fail + * with ESRCH. + */ + child_pid = fork(); + ASSERT_NE(child_pid, -1); + + if (child_pid == 0) + exit(0); + + pidfd = pidfd_open(child_pid, 0); + ASSERT_GE(pidfd, 0); + + /* Wait for the child to ensure it has terminated. */ + waitpid(child_pid, NULL, 0); + + ret = sys_process_madvise(pidfd, &vec, 1, MADV_DONTNEED, 0); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, ESRCH); + close(pidfd); +} + +/* + * Test process_madvise() with an invalid flag value. Now we only support flag=0 + * future we will use it support sync so reserve this test. + */ +TEST_F(process_madvise, flag) +{ + const unsigned long pagesize = (unsigned long)sysconf(_SC_PAGESIZE); + unsigned int invalid_flag; + struct iovec vec; + char *map; + ssize_t ret; + + map = mmap(NULL, pagesize, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, + 0); + if (map == MAP_FAILED) + ksft_exit_skip("mmap failed, not enough memory.\n"); + + vec.iov_base = map; + vec.iov_len = pagesize; + + invalid_flag = 0x80000000; + + ret = sys_process_madvise(PIDFD_SELF, &vec, 1, MADV_DONTNEED, + invalid_flag); + ASSERT_EQ(ret, -1); + ASSERT_EQ(errno, EINVAL); + + /* Cleanup. */ + ASSERT_EQ(munmap(map, pagesize), 0); +} + +TEST_HARNESS_MAIN diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index dddd1dd8af14..84fb51902c3e 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -65,6 +65,8 @@ separated by spaces: test pagemap_scan IOCTL - pfnmap tests for VM_PFNMAP handling +- process_madv + test process_madvise - cow test copy-on-write semantics - thp @@ -422,6 +424,9 @@ CATEGORY="hmm" run_test bash ./test_hmm.sh smoke # MADV_GUARD_INSTALL and MADV_GUARD_REMOVE tests CATEGORY="madv_guard" run_test ./guard-regions +# PROCESS_MADVISE TEST +CATEGORY="process_madv" run_test ./process_madv + # MADV_POPULATE_READ and MADV_POPULATE_WRITE tests CATEGORY="madv_populate" run_test ./madv_populate diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c index 5492e3f784df..85b209260e5a 100644 --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -20,6 +20,9 @@ unsigned int __page_size; unsigned int __page_shift; +volatile sig_atomic_t signal_jump_set; +sigjmp_buf signal_jmp_buf; + uint64_t pagemap_get_entry(int fd, char *start) { const unsigned long pfn = (unsigned long)start / getpagesize(); @@ -524,3 +527,35 @@ int read_sysfs(const char *file_path, unsigned long *val) return 0; } + +static void handle_fatal(int c) +{ + if (!signal_jump_set) + return; + + siglongjmp(signal_jmp_buf, c); +} + +void setup_sighandler(void) +{ + struct sigaction act = { + .sa_handler = &handle_fatal, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + if (sigaction(SIGSEGV, &act, NULL)) + ksft_exit_fail_perror("sigaction in setup"); +} + +void teardown_sighandler(void) +{ + struct sigaction act = { + .sa_handler = SIG_DFL, + .sa_flags = SA_NODEFER, + }; + + sigemptyset(&act.sa_mask); + if (sigaction(SIGSEGV, &act, NULL)) + ksft_exit_fail_perror("sigaction in teardown"); +} diff --git a/tools/testing/selftests/mm/vm_util.h b/tools/testing/selftests/mm/vm_util.h index b8136d12a0f8..6bc4177a2807 100644 --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -8,6 +8,8 @@ #include <unistd.h> /* _SC_PAGESIZE */ #include "../kselftest.h" #include <linux/fs.h> +#include <setjmp.h> +#include <signal.h> #define BIT_ULL(nr) (1ULL << (nr)) #define PM_SOFT_DIRTY BIT_ULL(55) @@ -61,6 +63,24 @@ static inline void skip_test_dodgy_fs(const char *op_name) ksft_test_result_skip("%s failed with ENOENT. Filesystem might be buggy (9pfs?)\n", op_name); } +/* + * Ignore the checkpatch warning, as per the C99 standard, section 7.14.1.1: + * + * "If the signal occurs other than as the result of calling the abort or raise + * function, the behavior is undefined if the signal handler refers to any + * object with static storage duration other than by assigning a value to an + * object declared as volatile sig_atomic_t" + */ +extern volatile sig_atomic_t signal_jump_set; +extern sigjmp_buf signal_jmp_buf; + +/* + * Ignore the checkpatch warning, we must read from x but don't want to do + * anything with it in order to trigger a read page fault. We therefore must use + * volatile to stop the compiler from optimising this away. + */ +#define FORCE_READ(x) (*(volatile typeof(x) *)x) + uint64_t pagemap_get_entry(int fd, char *start); bool pagemap_is_softdirty(int fd, char *start); bool pagemap_is_swapped(int fd, char *start); @@ -90,6 +110,8 @@ bool find_vma_procmap(struct procmap_fd *procmap, void *address); int close_procmap(struct procmap_fd *procmap); int write_sysfs(const char *file_path, unsigned long val); int read_sysfs(const char *file_path, unsigned long *val); +void setup_sighandler(void); +void teardown_sighandler(void); static inline int open_self_procmap(struct procmap_fd *procmap_out) { -- 2.43.0

2 months

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[PATCH bpf-next 0/3] bpf: Show precise rejected function when attaching to __noreturn and __btf_id functions

by KaFai Wan

Show precise rejected function name when attaching to __noreturn and __btf_id functions. Add selftest for attaching tracing to __btf_id functions. --- KaFai Wan (3): bpf: Show precise rejected function when attaching to __noreturn functions bpf: Show precise rejected function when attaching to __btf_id functions selftests/bpf: Add selftest for attaching tracing to __btf_id functions kernel/bpf/verifier.c | 5 ++++- .../selftests/bpf/prog_tests/tracing_btf_ids.c | 16 ++++++++++++++++ .../selftests/bpf/progs/fexit_noreturns.c | 2 +- .../selftests/bpf/progs/tracing_btf_ids.c | 15 +++++++++++++++ 4 files changed, 36 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/tracing_btf_ids.c create mode 100644 tools/testing/selftests/bpf/progs/tracing_btf_ids.c -- 2.43.0

2 months

3
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[PATCH 00/10] mm/mremap: permit mremap() move of multiple VMAs

by Lorenzo Stoakes

Historically we've made it a uAPI requirement that mremap() may only operate on a single VMA at a time. For instances where VMAs need to be resized, this makes sense, as it becomes very difficult to determine what a user actually wants should they indicate a desire to expand or shrink the size of multiple VMAs (truncate? Adjust sizes individually? Some other strategy?). However, in instances where a user is moving VMAs, it is restrictive to disallow this. This is especially the case when anonymous mapping remap may or may not be mergeable depending on whether VMAs have or have not been faulted due to anon_vma assignment and folio index alignment with vma->vm_pgoff. Often this can result in surprising impact where a moved region is faulted, then moved back and a user fails to observe a merge from otherwise compatible, adjacent VMAs. This change allows such cases to work without the user having to be cognizant of whether a prior mremap() move or other VMA operations has resulted in VMA fragmentation. In order to do this, this series performs a large amount of refactoring, most pertinently - grouping sanity checks together, separately those that check input parameters and those relating to VMAs. we also simplify the post-mmap lock drop processing for uffd and mlock()'d VMAs. With this done, we can then fairly straightforwardly implement this functionality. This works exclusively for mremap() invocations which specify MREMAP_FIXED. It is not compatible with VMAs which use userfaultfd, as the notification of the userland fault handler would require us to drop the mmap lock. The input and output addresses ranges must not overlap. We carefully account for moves which would result in VMA merges or would otherwise result in VMA iterator invalidation. Lorenzo Stoakes (10): mm/mremap: perform some simple cleanups mm/mremap: refactor initial parameter sanity checks mm/mremap: put VMA check and prep logic into helper function mm/mremap: cleanup post-processing stage of mremap mm/mremap: use an explicit uffd failure path for mremap mm/mremap: check remap conditions earlier mm/mremap: move remap_is_valid() into check_prep_vma() mm/mremap: clean up mlock populate behaviour mm/mremap: permit mremap() move of multiple VMAs tools/testing/selftests: extend mremap_test to test multi-VMA mremap fs/userfaultfd.c | 15 +- include/linux/userfaultfd_k.h | 1 + mm/mremap.c | 502 ++++++++++++++--------- tools/testing/selftests/mm/mremap_test.c | 145 ++++++- 4 files changed, 462 insertions(+), 201 deletions(-) -- 2.50.0

2 months

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Linux-kselftest-mirror July 2025