- Linux-kselftest-mirror - lists.linaro.org

[PATCH] selftests: livepatch: use canonical ftrace path

by Fushuai Wang

Since v4.1 kernel, a new interface for ftrace called "tracefs" was introduced, which is usually mounted in /sys/kernel/tracing. Therefore, tracing files can now be accessed via either the legacy path /sys/kernel/debug/tracing or the newer path /sys/kernel/tracing. Signed-off-by: Fushuai Wang <wangfushuai(a)baidu.com> --- tools/testing/selftests/livepatch/functions.sh | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh index 46991a029f7c..8ec0cb64ad94 100644 --- a/tools/testing/selftests/livepatch/functions.sh +++ b/tools/testing/selftests/livepatch/functions.sh @@ -10,7 +10,11 @@ SYSFS_KERNEL_DIR="/sys/kernel" SYSFS_KLP_DIR="$SYSFS_KERNEL_DIR/livepatch" SYSFS_DEBUG_DIR="$SYSFS_KERNEL_DIR/debug" SYSFS_KPROBES_DIR="$SYSFS_DEBUG_DIR/kprobes" -SYSFS_TRACING_DIR="$SYSFS_DEBUG_DIR/tracing" +if [[ -e /sys/kernel/tracing/trace ]]; then + SYSFS_TRACING_DIR="$SYSFS_KERNEL_DIR/tracing" +else + SYSFS_TRACING_DIR="$SYSFS_DEBUG_DIR/tracing" +fi # Kselftest framework requirement - SKIP code is 4 ksft_skip=4 -- 2.36.1

3 weeks, 2 days

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[PATCH v22 0/8] fork: Support shadow stacks in clone3()

by Mark Brown

At this point I think everyone in the on the kernel side is happy with this but there were some questions from the glibc side about the value of controlling the shadow stack placement and size, especially with the current inability to reuse the shadow stack for an exited thread. With support for reuse it would be possible to have a cache of shadow stacks as is currently supported for the normal stack. Since the discussion petered out I'm resending this in order to give people something work with while prototyping. It should be possible to prototype any potential kernel features to help build out shadow stack support in userspace by enabling shadow stack writes, as suggested by Rick Edgecombe this may end up being required anyway for supporting more exotic scenarios. On all current architectures with the feature writes to shadow stack require specific instructions so there are still security benefits even with writes enabled. I did send a change implementing a feature writing a token on thread exit to allow reuse: https://lore.kernel.org/r/20250921-arm64-gcs-exit-token-v1-0-45cf64e648d5@k… but wasn't planning to refresh it without some indication from the userspace side that that'd be useful. Non-process cover letter: The kernel has added support for shadow stacks, currently x86 only using their CET feature but both arm64 and RISC-V have equivalent features (GCS and Zicfiss respectively), I am actively working on GCS[1]. With shadow stacks the hardware maintains an additional stack containing only the return addresses for branch instructions which is not generally writeable by userspace and ensures that any returns are to the recorded addresses. This provides some protection against ROP attacks and making it easier to collect call stacks. These shadow stacks are allocated in the address space of the userspace process. Our API for shadow stacks does not currently offer userspace any flexiblity for managing the allocation of shadow stacks for newly created threads, instead the kernel allocates a new shadow stack with the same size as the normal stack whenever a thread is created with the feature enabled. The stacks allocated in this way are freed by the kernel when the thread exits or shadow stacks are disabled for the thread. This lack of flexibility and control isn't ideal, in the vast majority of cases the shadow stack will be over allocated and the implicit allocation and deallocation is not consistent with other interfaces. As far as I can tell the interface is done in this manner mainly because the shadow stack patches were in development since before clone3() was implemented. Since clone3() is readily extensible let's add support for specifying a shadow stack when creating a new thread or process, keeping the current implicit allocation behaviour if one is not specified either with clone3() or through the use of clone(). The user must provide a shadow stack pointer, this must point to memory mapped for use as a shadow stackby map_shadow_stack() with an architecture specified shadow stack token at the top of the stack. Yuri Khrustalev has raised questions from the libc side regarding discoverability of extended clone3() structure sizes[2], this seems like a general issue with clone3(). There was a suggestion to add a hwcap on arm64 which isn't ideal but is doable there, though architecture specific mechanisms would also be needed for x86 (and RISC-V if it's support gets merged before this does). The idea has, however, had strong pushback from the architecture maintainers and it is possible to detect support for this in clone3() by attempting a call with a misaligned shadow stack pointer specified so no hwcap has been added. [1] https://lore.kernel.org/linux-arm-kernel/20241001-arm64-gcs-v13-0-222b78d87… [2] https://lore.kernel.org/r/aCs65ccRQtJBnZ_5@arm.com Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v22: - Rebase onto v6.18-rc1. - Cover letter updates. - Link to v21: https://lore.kernel.org/r/20250916-clone3-shadow-stack-v21-0-910493527013@k… Changes in v21: - Rebase onto https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git kernel-6.18.clone3 - Rename shadow_stack_token to shstk_token, since it's a simple rename I've kept the acks and reviews but I dropped the tested-bys just to be safe. - Link to v20: https://lore.kernel.org/r/20250902-clone3-shadow-stack-v20-0-4d9fff1c53e7@k… Changes in v20: - Comment fixes and clarifications in x86 arch_shstk_validate_clone() from Rick Edgecombe. - Spelling fix in documentation. - Link to v19: https://lore.kernel.org/r/20250819-clone3-shadow-stack-v19-0-bc957075479b@k… Changes in v19: - Rebase onto v6.17-rc1. - Link to v18: https://lore.kernel.org/r/20250702-clone3-shadow-stack-v18-0-7965d2b694db@k… Changes in v18: - Rebase onto v6.16-rc3. - Thanks to pointers from Yuri Khrustalev this version has been tested on x86 so I have removed the RFT tag. - Clarify clone3_shadow_stack_valid() comment about the Kconfig check. - Remove redundant GCSB DSYNCs in arm64 code. - Fix token validation on x86. - Link to v17: https://lore.kernel.org/r/20250609-clone3-shadow-stack-v17-0-8840ed97ff6f@k… Changes in v17: - Rebase onto v6.16-rc1. - Link to v16: https://lore.kernel.org/r/20250416-clone3-shadow-stack-v16-0-2ffc9ca3917b@k… Changes in v16: - Rebase onto v6.15-rc2. - Roll in fixes from x86 testing from Rick Edgecombe. - Rework so that the argument is shadow_stack_token. - Link to v15: https://lore.kernel.org/r/20250408-clone3-shadow-stack-v15-0-3fa245c6e3be@k… Changes in v15: - Rebase onto v6.15-rc1. - Link to v14: https://lore.kernel.org/r/20250206-clone3-shadow-stack-v14-0-805b53af73b9@k… Changes in v14: - Rebase onto v6.14-rc1. - Link to v13: https://lore.kernel.org/r/20241203-clone3-shadow-stack-v13-0-93b89a81a5ed@k… Changes in v13: - Rebase onto v6.13-rc1. - Link to v12: https://lore.kernel.org/r/20241031-clone3-shadow-stack-v12-0-7183eb8bee17@k… Changes in v12: - Add the regular prctl() to the userspace API document since arm64 support is queued in -next. - Link to v11: https://lore.kernel.org/r/20241005-clone3-shadow-stack-v11-0-2a6a2bd6d651@k… Changes in v11: - Rebase onto arm64 for-next/gcs, which is based on v6.12-rc1, and integrate arm64 support. - Rework the interface to specify a shadow stack pointer rather than a base and size like we do for the regular stack. - Link to v10: https://lore.kernel.org/r/20240821-clone3-shadow-stack-v10-0-06e8797b9445@k… Changes in v10: - Integrate fixes & improvements for the x86 implementation from Rick Edgecombe. - Require that the shadow stack be VM_WRITE. - Require that the shadow stack base and size be sizeof(void *) aligned. - Clean up trailing newline. - Link to v9: https://lore.kernel.org/r/20240819-clone3-shadow-stack-v9-0-962d74f99464@ke… Changes in v9: - Pull token validation earlier and report problems with an error return to parent rather than signal delivery to the child. - Verify that the top of the supplied shadow stack is VM_SHADOW_STACK. - Rework token validation to only do the page mapping once. - Drop no longer needed support for testing for signals in selftest. - Fix typo in comments. - Link to v8: https://lore.kernel.org/r/20240808-clone3-shadow-stack-v8-0-0acf37caf14c@ke… Changes in v8: - Fix token verification with user specified shadow stack. - Don't track user managed shadow stacks for child processes. - Link to v7: https://lore.kernel.org/r/20240731-clone3-shadow-stack-v7-0-a9532eebfb1d@ke… Changes in v7: - Rebase onto v6.11-rc1. - Typo fixes. - Link to v6: https://lore.kernel.org/r/20240623-clone3-shadow-stack-v6-0-9ee7783b1fb9@ke… Changes in v6: - Rebase onto v6.10-rc3. - Ensure we don't try to free the parent shadow stack in error paths of x86 arch code. - Spelling fixes in userspace API document. - Additional cleanups and improvements to the clone3() tests to support the shadow stack tests. - Link to v5: https://lore.kernel.org/r/20240203-clone3-shadow-stack-v5-0-322c69598e4b@ke… Changes in v5: - Rebase onto v6.8-rc2. - Rework ABI to have the user allocate the shadow stack memory with map_shadow_stack() and a token. - Force inlining of the x86 shadow stack enablement. - Move shadow stack enablement out into a shared header for reuse by other tests. - Link to v4: https://lore.kernel.org/r/20231128-clone3-shadow-stack-v4-0-8b28ffe4f676@ke… Changes in v4: - Formatting changes. - Use a define for minimum shadow stack size and move some basic validation to fork.c. - Link to v3: https://lore.kernel.org/r/20231120-clone3-shadow-stack-v3-0-a7b8ed3e2acc@ke… Changes in v3: - Rebase onto v6.7-rc2. - Remove stale shadow_stack in internal kargs. - If a shadow stack is specified unconditionally use it regardless of CLONE_ parameters. - Force enable shadow stacks in the selftest. - Update changelogs for RISC-V feature rename. - Link to v2: https://lore.kernel.org/r/20231114-clone3-shadow-stack-v2-0-b613f8681155@ke… Changes in v2: - Rebase onto v6.7-rc1. - Remove ability to provide preallocated shadow stack, just specify the desired size. - Link to v1: https://lore.kernel.org/r/20231023-clone3-shadow-stack-v1-0-d867d0b5d4d0@ke… --- Mark Brown (8): arm64/gcs: Return a success value from gcs_alloc_thread_stack() Documentation: userspace-api: Add shadow stack API documentation selftests: Provide helper header for shadow stack testing fork: Add shadow stack support to clone3() selftests/clone3: Remove redundant flushes of output streams selftests/clone3: Factor more of main loop into test_clone3() selftests/clone3: Allow tests to flag if -E2BIG is a valid error code selftests/clone3: Test shadow stack support Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/shadow_stack.rst | 44 +++++ arch/arm64/include/asm/gcs.h | 8 +- arch/arm64/kernel/process.c | 8 +- arch/arm64/mm/gcs.c | 55 +++++- arch/x86/include/asm/shstk.h | 11 +- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/shstk.c | 53 ++++- include/asm-generic/cacheflush.h | 11 ++ include/linux/sched/task.h | 17 ++ include/uapi/linux/sched.h | 9 +- kernel/fork.c | 93 +++++++-- tools/testing/selftests/clone3/clone3.c | 226 ++++++++++++++++++---- tools/testing/selftests/clone3/clone3_selftests.h | 65 ++++++- tools/testing/selftests/ksft_shstk.h | 98 ++++++++++ 15 files changed, 620 insertions(+), 81 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20231019-clone3-shadow-stack-15d40d2bf536 Best regards, -- Mark Brown <broonie(a)kernel.org>

3 weeks, 2 days

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[PATCH v2 0/3] selftests/filelock: Make output more kselftestish

by Mark Brown

This series makes the output from the ofdlocks test a bit easier for tooling to work with, and also ignores the generated file while we're here. Signed-off-by: Mark Brown <broonie(a)kernel.org> --- Changes in v2: - Rebase onto v6.18-rc1. - Link to v1: https://lore.kernel.org/r/20250818-selftest-filelock-ktap-v1-0-d41af77f1396… --- Mark Brown (3): kselftest/filelock: Use ksft_perror() kselftest/filelock: Report each test in oftlocks separately kselftest/filelock: Add a .gitignore file tools/testing/selftests/filelock/.gitignore | 1 + tools/testing/selftests/filelock/ofdlocks.c | 94 +++++++++++++---------------- 2 files changed, 42 insertions(+), 53 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20250604-selftest-filelock-ktap-f2ae998a0de0 Best regards, -- Mark Brown <broonie(a)kernel.org>

3 weeks, 2 days

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selftests/mm/rmap: verify correct RMAP handling of COW pages after fork()

by Itamar Dalal

Add a new test `migrate.cow_after_fork` that verifies correct RMAP handling of Copy-On-Write (COW) pages after fork(). Before a write, the parent and child share the same PFN. After a write, the child’s PFN differs. This confirms that proper COW duplication occurred and that RMAP correctly tracks page ownership transitions during COW events. Signed-off-by: Itamar-Dalal <dalalitamar(a)gmail.com> --- tools/testing/selftests/mm/rmap.c | 45 ++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/rmap.c b/tools/testing/selftests/mm/rmap.c index 13f7bccfd0a9..2ba3361fecf0 100644 --- a/tools/testing/selftests/mm/rmap.c +++ b/tools/testing/selftests/mm/rmap.c @@ -430,4 +430,47 @@ TEST_F(migrate, ksm) propagate_children(_metadata, data); } -TEST_HARNESS_MAIN +TEST_F(migrate, cow_after_fork) +{ + struct global_data *data = &self->data; + int status; + pid_t pid; + unsigned long parent_pfn, child_pfn; + int pagemap_fd; + char *region; + + /* Map private anonymous memory and fault it in */ + region = mmap(NULL, data->mapsize, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(region, MAP_FAILED); + memset(region, 0xaa, data->mapsize); + + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(pagemap_fd, -1); + parent_pfn = pagemap_get_pfn(pagemap_fd, region); + close(pagemap_fd); + + pid = fork(); + ASSERT_NE(pid, -1); + + if (pid == 0) { + /* Child: write to trigger COW */ + region[0] = 0xbb; + + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(pagemap_fd, -1); + child_pfn = pagemap_get_pfn(pagemap_fd, region); + close(pagemap_fd); + + /* Expect PFN to differ after write (COW happened) */ + if (child_pfn == parent_pfn) + _exit(FAIL_ON_CHECK); + _exit(0); + } + + waitpid(pid, &status, 0); + ASSERT_EQ(WEXITSTATUS(status), 0); + munmap(region, data->mapsize); +} + +TEST_HARNESS_MAIN \ No newline at end of file -- 2.34.1

3 weeks, 2 days

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Re: selftests/mm/rmap: verify correct RMAP handling of COW pages after fork()

by David Hildenbrand

On 15.10.25 10:33, Itamar Dalal wrote: > Add a new test `migrate.cow_after_fork` that verifies correct RMAP handling > of Copy-On-Write (COW) pages after fork(). > > Before a write, the parent and child share the same PFN. After a write, the > child’s PFN differs. This confirms that proper COW duplication occurred and > that RMAP correctly tracks page ownership transitions during COW events. > > Signed-off-by: Itamar-Dalal <dalalitamar(a)gmail.com > <mailto:dalalitamar@gmail.com>> > --- > tools/testing/selftests/mm/rmap.c | 45 ++++++++++++++++++++++++++++++- > 1 file changed, 44 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/mm/rmap.c b/tools/testing/ > selftests/mm/rmap.c > index 13f7bccfd0a9..2ba3361fecf0 100644 > --- a/tools/testing/selftests/mm/rmap.c > +++ b/tools/testing/selftests/mm/rmap.c > @@ -430,4 +430,47 @@ TEST_F(migrate, ksm) > propagate_children(_metadata, data); > } > > -TEST_HARNESS_MAIN > +TEST_F(migrate, cow_after_fork) > +{ > + struct global_data *data = &self->data; > + int status; > + pid_t pid; > + unsigned long parent_pfn, child_pfn; > + int pagemap_fd; > + char *region; > + > + /* Map private anonymous memory and fault it in */ > + region = mmap(NULL, data->mapsize, PROT_READ | PROT_WRITE, > + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); > + ASSERT_NE(region, MAP_FAILED); > + memset(region, 0xaa, data->mapsize); > + > + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); > + ASSERT_NE(pagemap_fd, -1); > + parent_pfn = pagemap_get_pfn(pagemap_fd, region); > + close(pagemap_fd); > + > + pid = fork(); > + ASSERT_NE(pid, -1); > + > + if (pid == 0) { > + /* Child: write to trigger COW */ > + region[0] = 0xbb; > + > + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); > + ASSERT_NE(pagemap_fd, -1); > + child_pfn = pagemap_get_pfn(pagemap_fd, region); > + close(pagemap_fd); > + > + /* Expect PFN to differ after write (COW happened) */ > + if (child_pfn == parent_pfn) > + _exit(FAIL_ON_CHECK); > + _exit(0); > + } > + > + waitpid(pid, &status, 0); > + ASSERT_EQ(WEXITSTATUS(status), 0); > + munmap(region, data->mapsize); > +} We have excessive cow tests in cow.c, that are independent of any PFN checks. So I don't think we need this. BTW, I never received a mail that shows up right-aligned in my mail client. Seems to be because of Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable <div dir=3D"rtl" The whole attachment should be dropped. Did you send this with git-send-email? :) -- Cheers David / dhildenb

3 weeks, 2 days

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[PATCH][v3] hung_task: Panic after fixed number of hung tasks

by lirongqing

From: Li RongQing <lirongqing(a)baidu.com> Currently, when 'hung_task_panic' is enabled, the kernel panics immediately upon detecting the first hung task. However, some hung tasks are transient and the system can recover, while others are persistent and may accumulate progressively. This patch extends the 'hung_task_panic' sysctl to allow specifying the number of hung tasks that must be detected before triggering a kernel panic. This provides finer control for environments where transient hangs may occur but persistent hangs should still be fatal. The sysctl can be set to: - 0: disabled (never panic) - 1: original behavior (panic on first hung task) - N: panic when N hung tasks are detected This maintains backward compatibility while providing more flexibility for handling different hang scenarios. Signed-off-by: Li RongQing <lirongqing(a)baidu.com> --- Diff with v2: not add new sysctl, extend hung_task_panic Documentation/admin-guide/kernel-parameters.txt | 20 +++++++++++++------- Documentation/admin-guide/sysctl/kernel.rst | 3 ++- arch/arm/configs/aspeed_g5_defconfig | 2 +- kernel/configs/debug.config | 2 +- kernel/hung_task.c | 16 +++++++++++----- lib/Kconfig.debug | 10 ++++++---- tools/testing/selftests/wireguard/qemu/kernel.config | 2 +- 7 files changed, 35 insertions(+), 20 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index a51ab46..7d9a8ee 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1992,14 +1992,20 @@ the added memory block itself do not be affected. hung_task_panic= - [KNL] Should the hung task detector generate panics. - Format: 0 | 1 + [KNL] Number of hung tasks to trigger kernel panic. + Format: <int> + + Set this to the number of hung tasks that must be + detected before triggering a kernel panic. + + 0: don't panic + 1: panic immediately on first hung task + N: panic after N hung tasks are detect - A value of 1 instructs the kernel to panic when a - hung task is detected. The default value is controlled - by the CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time - option. The value selected by this boot parameter can - be changed later by the kernel.hung_task_panic sysctl. + The default value is controlled by the + CONFIG_BOOTPARAM_HUNG_TASK_PANIC build-time option. The value + selected by this boot parameter can be changed later by the + kernel.hung_task_panic sysctl. hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC) terminal devices. Valid values: 0..8 diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index f3ee807..0a8dfab 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -397,7 +397,8 @@ a hung task is detected. hung_task_panic =============== -Controls the kernel's behavior when a hung task is detected. +When set to a non-zero value, a kernel panic will be triggered if the +number of detected hung tasks reaches this value This file shows up if ``CONFIG_DETECT_HUNG_TASK`` is enabled. = ================================================= diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig index 61cee1e..c3b0d5f 100644 --- a/arch/arm/configs/aspeed_g5_defconfig +++ b/arch/arm/configs/aspeed_g5_defconfig @@ -308,7 +308,7 @@ CONFIG_PANIC_ON_OOPS=y CONFIG_PANIC_TIMEOUT=-1 CONFIG_SOFTLOCKUP_DETECTOR=y CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y -CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1 CONFIG_WQ_WATCHDOG=y # CONFIG_SCHED_DEBUG is not set CONFIG_FUNCTION_TRACER=y diff --git a/kernel/configs/debug.config b/kernel/configs/debug.config index e81327d..9f6ab7d 100644 --- a/kernel/configs/debug.config +++ b/kernel/configs/debug.config @@ -83,7 +83,7 @@ CONFIG_SLUB_DEBUG_ON=y # # Debug Oops, Lockups and Hangs # -# CONFIG_BOOTPARAM_HUNG_TASK_PANIC is not set +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=0 # CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC is not set CONFIG_DEBUG_ATOMIC_SLEEP=y CONFIG_DETECT_HUNG_TASK=y diff --git a/kernel/hung_task.c b/kernel/hung_task.c index b2c1f14..3929ed9 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -81,7 +81,7 @@ static unsigned int __read_mostly sysctl_hung_task_all_cpu_backtrace; * hung task is detected: */ static unsigned int __read_mostly sysctl_hung_task_panic = - IS_ENABLED(CONFIG_BOOTPARAM_HUNG_TASK_PANIC); + CONFIG_BOOTPARAM_HUNG_TASK_PANIC; static int hung_task_panic(struct notifier_block *this, unsigned long event, void *ptr) @@ -218,8 +218,11 @@ static inline void debug_show_blocker(struct task_struct *task, unsigned long ti } #endif -static void check_hung_task(struct task_struct *t, unsigned long timeout) +static void check_hung_task(struct task_struct *t, unsigned long timeout, + unsigned long prev_detect_count) { + unsigned long total_hung_task; + if (!task_is_hung(t, timeout)) return; @@ -229,9 +232,11 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) */ sysctl_hung_task_detect_count++; + total_hung_task = sysctl_hung_task_detect_count - prev_detect_count; trace_sched_process_hang(t); - if (sysctl_hung_task_panic) { + if (sysctl_hung_task_panic && + (total_hung_task >= sysctl_hung_task_panic)) { console_verbose(); hung_task_show_lock = true; hung_task_call_panic = true; @@ -300,6 +305,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) int max_count = sysctl_hung_task_check_count; unsigned long last_break = jiffies; struct task_struct *g, *t; + unsigned long prev_detect_count = sysctl_hung_task_detect_count; /* * If the system crashed already then all bets are off, @@ -320,7 +326,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) last_break = jiffies; } - check_hung_task(t, timeout); + check_hung_task(t, timeout, prev_detect_count); } unlock: rcu_read_unlock(); @@ -389,7 +395,7 @@ static const struct ctl_table hung_task_sysctls[] = { .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = SYSCTL_ZERO, - .extra2 = SYSCTL_ONE, + .extra2 = SYSCTL_INT_MAX, }, { .procname = "hung_task_check_count", diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 3034e294..077b9e4 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -1258,12 +1258,14 @@ config DEFAULT_HUNG_TASK_TIMEOUT Keeping the default should be fine in most cases. config BOOTPARAM_HUNG_TASK_PANIC - bool "Panic (Reboot) On Hung Tasks" + int "Number of hung tasks to trigger kernel panic" depends on DETECT_HUNG_TASK + default 0 help - Say Y here to enable the kernel to panic on "hung tasks", - which are bugs that cause the kernel to leave a task stuck - in uninterruptible "D" state. + The number of hung tasks must be detected to trigger kernel panic. + + - 0: Don't trigger panic + - N: Panic when N hung tasks are detected The panic can be used in combination with panic_timeout, to cause the system to reboot automatically after a diff --git a/tools/testing/selftests/wireguard/qemu/kernel.config b/tools/testing/selftests/wireguard/qemu/kernel.config index 936b18b..0504c11 100644 --- a/tools/testing/selftests/wireguard/qemu/kernel.config +++ b/tools/testing/selftests/wireguard/qemu/kernel.config @@ -81,7 +81,7 @@ CONFIG_WQ_WATCHDOG=y CONFIG_DETECT_HUNG_TASK=y CONFIG_BOOTPARAM_HARDLOCKUP_PANIC=y CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y -CONFIG_BOOTPARAM_HUNG_TASK_PANIC=y +CONFIG_BOOTPARAM_HUNG_TASK_PANIC=1 CONFIG_PANIC_TIMEOUT=-1 CONFIG_STACKTRACE=y CONFIG_EARLY_PRINTK=y -- 2.9.4

3 weeks, 3 days

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[PATCH] Add a new test 'migrate.cow_after_fork' that verifies correct RMAP handling of Copy-On-Write pages after fork(). Before a write, parent and child share the same PFN; after a write, the child’s PFN differs, confirming proper COW duplication.

by Itamar-Dalal

Signed-off-by: Itamar-Dalal <dalalitamar(a)gmail.com> --- tools/testing/selftests/mm/rmap.c | 45 ++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/rmap.c b/tools/testing/selftests/mm/rmap.c index 13f7bccfd0a9..2ba3361fecf0 100644 --- a/tools/testing/selftests/mm/rmap.c +++ b/tools/testing/selftests/mm/rmap.c @@ -430,4 +430,47 @@ TEST_F(migrate, ksm) propagate_children(_metadata, data); } -TEST_HARNESS_MAIN +TEST_F(migrate, cow_after_fork) +{ + struct global_data *data = &self->data; + int status; + pid_t pid; + unsigned long parent_pfn, child_pfn; + int pagemap_fd; + char *region; + + /* Map private anonymous memory and fault it in */ + region = mmap(NULL, data->mapsize, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + ASSERT_NE(region, MAP_FAILED); + memset(region, 0xaa, data->mapsize); + + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(pagemap_fd, -1); + parent_pfn = pagemap_get_pfn(pagemap_fd, region); + close(pagemap_fd); + + pid = fork(); + ASSERT_NE(pid, -1); + + if (pid == 0) { + /* Child: write to trigger COW */ + region[0] = 0xbb; + + pagemap_fd = open("/proc/self/pagemap", O_RDONLY); + ASSERT_NE(pagemap_fd, -1); + child_pfn = pagemap_get_pfn(pagemap_fd, region); + close(pagemap_fd); + + /* Expect PFN to differ after write (COW happened) */ + if (child_pfn == parent_pfn) + _exit(FAIL_ON_CHECK); + _exit(0); + } + + waitpid(pid, &status, 0); + ASSERT_EQ(WEXITSTATUS(status), 0); + munmap(region, data->mapsize); +} + +TEST_HARNESS_MAIN \ No newline at end of file -- 2.34.1

3 weeks, 3 days

2
1
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[PATCH] selftests/dma: add dma_map_benchmark to .gitignore

by Kriish Sharma

Add the dma_map_benchmark binary to .gitignore to prevent it from being shown as an untracked file after building the selftests. Signed-off-by: Kriish Sharma <kriish.sharma2006(a)gmail.com> --- tools/testing/selftests/dma/.gitignore | 2 ++ 1 file changed, 2 insertions(+) create mode 100644 tools/testing/selftests/dma/.gitignore diff --git a/tools/testing/selftests/dma/.gitignore b/tools/testing/selftests/dma/.gitignore new file mode 100644 index 000000000000..b4b99b6ffea3 --- /dev/null +++ b/tools/testing/selftests/dma/.gitignore @@ -0,0 +1,2 @@ +# SPDX-License-Identifier: GPL-2.0-only +dma_map_benchmark -- 2.34.1

3 weeks, 3 days

1
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[PATCH v2] selftests/run_kselftest.sh: exit with error if tests fail

by Brendan Jackman

Parsing KTAP is quite an inconvenience, but most of the time the thing you really want to know is "did anything fail"? Let's give the user the his information without them needing to parse anything. Because of the use of subshells and namespaces, this needs to be communicated via a file. Just write arbitrary data into the file and treat non-empty content as a signal that something failed. In case any user depends on the current behaviour, such as running this from a script with `set -e` and parsing the result for failures afterwards, add a flag they can set to get the old behaviour, namely --no-error-on-fail. Signed-off-by: Brendan Jackman <jackmanb(a)google.com> --- Changes in v2: - Fixed bug in report_failure() - Made error-on-fail the default - Link to v1: https://lore.kernel.org/r/20251007-b4-ksft-error-on-fail-v1-1-71bf058f5662@… --- tools/testing/selftests/kselftest/runner.sh | 14 ++++++++++---- tools/testing/selftests/run_kselftest.sh | 14 ++++++++++++++ 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/kselftest/runner.sh b/tools/testing/selftests/kselftest/runner.sh index 2c3c58e65a419f5ee8d7dc51a37671237a07fa0b..3a62039fa6217f3453423ff011575d0a1eb8c275 100644 --- a/tools/testing/selftests/kselftest/runner.sh +++ b/tools/testing/selftests/kselftest/runner.sh @@ -44,6 +44,12 @@ tap_timeout() fi } +report_failure() +{ + echo "not ok $*" + echo "$*" >> "$kselftest_failures_file" +} + run_one() { DIR="$1" @@ -105,7 +111,7 @@ run_one() echo "# $TEST_HDR_MSG" if [ ! -e "$TEST" ]; then echo "# Warning: file $TEST is missing!" - echo "not ok $test_num $TEST_HDR_MSG" + report_failure "$test_num $TEST_HDR_MSG" else if [ -x /usr/bin/stdbuf ]; then stdbuf="/usr/bin/stdbuf --output=L " @@ -123,7 +129,7 @@ run_one() interpreter=$(head -n 1 "$TEST" | cut -c 3-) cmd="$stdbuf $interpreter ./$BASENAME_TEST" else - echo "not ok $test_num $TEST_HDR_MSG" + report_failure "$test_num $TEST_HDR_MSG" return fi fi @@ -137,9 +143,9 @@ run_one() echo "ok $test_num $TEST_HDR_MSG # SKIP" elif [ $rc -eq $timeout_rc ]; then \ echo "#" - echo "not ok $test_num $TEST_HDR_MSG # TIMEOUT $kselftest_timeout seconds" + report_failure "$test_num $TEST_HDR_MSG # TIMEOUT $kselftest_timeout seconds" else - echo "not ok $test_num $TEST_HDR_MSG # exit=$rc" + report_failure "$test_num $TEST_HDR_MSG # exit=$rc" fi) cd - >/dev/null fi diff --git a/tools/testing/selftests/run_kselftest.sh b/tools/testing/selftests/run_kselftest.sh index 0443beacf3621ae36cb12ffd57f696ddef3526b5..cc1b4190edacedadafd9b993a351e4cfbf17ccd5 100755 --- a/tools/testing/selftests/run_kselftest.sh +++ b/tools/testing/selftests/run_kselftest.sh @@ -33,6 +33,7 @@ Usage: $0 [OPTIONS] -c | --collection COLLECTION Run all tests from COLLECTION -l | --list List the available collection:test entries -d | --dry-run Don't actually run any tests + -f | --no-error-on-fail Don't exit with an error just because tests failed -n | --netns Run each test in namespace -h | --help Show this usage info -o | --override-timeout Number of seconds after which we timeout @@ -44,6 +45,7 @@ COLLECTIONS="" TESTS="" dryrun="" kselftest_override_timeout="" +ERROR_ON_FAIL=true while true; do case "$1" in -s | --summary) @@ -65,6 +67,9 @@ while true; do -d | --dry-run) dryrun="echo" shift ;; + -f | --no-error-on-fail) + ERROR_ON_FAIL=false + shift ;; -n | --netns) RUN_IN_NETNS=1 shift ;; @@ -105,9 +110,18 @@ if [ -n "$TESTS" ]; then available="$(echo "$valid" | sed -e 's/ /\n/g')" fi +kselftest_failures_file=$(mktemp --tmpdir kselftest-failures-XXXXXX) +export kselftest_failures_file + collections=$(echo "$available" | cut -d: -f1 | sort | uniq) for collection in $collections ; do [ -w /dev/kmsg ] && echo "kselftest: Running tests in $collection" >> /dev/kmsg tests=$(echo "$available" | grep "^$collection:" | cut -d: -f2) ($dryrun cd "$collection" && $dryrun run_many $tests) done + +failures="$(cat "$kselftest_failures_file")" +rm "$kselftest_failures_file" +if "$ERROR_ON_FAIL" && [ "$failures" ]; then + exit 1 +fi --- base-commit: 8f5ae30d69d7543eee0d70083daf4de8fe15d585 change-id: 20251007-b4-ksft-error-on-fail-0c2cb3246041 Best regards, -- Brendan Jackman <jackmanb(a)google.com>

3 weeks, 3 days

1
1
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[PATCH bpf-next v2 0/3] Add overwrite mode for bpf ring buffer

by Xu Kuohai

When the bpf ring buffer is full, new events can not be recorded util the consumer consumes some events to free space. This may cause critical events to be discarded, such as in fault diagnostic, where recent events are more critical than older ones. So add ovewrite mode for bpf ring buffer. In this mode, the new event overwrites the oldest event when the buffer is full. v2: - remove libbpf changes (Andrii) - update overwrite benchmark v1: https://lore.kernel.org/bpf/20250804022101.2171981-1-xukuohai@huaweicloud.c… Xu Kuohai (3): bpf: Add overwrite mode for bpf ring buffer selftests/bpf: Add test for overwrite ring buffer selftests/bpf/benchs: Add producer and overwrite bench for ring buffer include/uapi/linux/bpf.h | 4 + kernel/bpf/ringbuf.c | 159 +++++++++++++++--- tools/include/uapi/linux/bpf.h | 4 + tools/testing/selftests/bpf/Makefile | 3 +- tools/testing/selftests/bpf/bench.c | 2 + .../selftests/bpf/benchs/bench_ringbufs.c | 95 ++++++++++- .../bpf/benchs/run_bench_ringbufs.sh | 4 + .../selftests/bpf/prog_tests/ringbuf.c | 74 ++++++++ .../selftests/bpf/progs/ringbuf_bench.c | 10 ++ .../bpf/progs/test_ringbuf_overwrite.c | 98 +++++++++++ 10 files changed, 418 insertions(+), 35 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_overwrite.c -- 2.43.0

3 weeks, 3 days

2
15
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