June 2024 - Linux-kselftest-mirror

[PATCH v5 00/28] NT synchronization primitive driver

by Elizabeth Figura

This patch series implements a new char misc driver, /dev/ntsync, which is used to implement Windows NT synchronization primitives. NT synchronization primitives are unique in that the wait functions both are vectored, operate on multiple types of object with different behaviour (mutex, semaphore, event), and affect the state of the objects they wait on. This model is not compatible with existing kernel synchronization objects or interfaces, and therefore the ntsync driver implements its own wait queues and locking. This patch series is rebased against the "char-misc-next" branch of gregkh/char-misc.git. == Background == The Wine project emulates the Windows API in user space. One particular part of that API, namely the NT synchronization primitives, have historically been implemented via RPC to a dedicated "kernel" process. However, more recent applications use these APIs more strenuously, and the overhead of RPC has become a bottleneck. The NT synchronization APIs are too complex to implement on top of existing primitives without sacrificing correctness. Certain operations, such as NtPulseEvent() or the "wait-for-all" mode of NtWaitForMultipleObjects(), require direct control over the underlying wait queue, and implementing a wait queue sufficiently robust for Wine in user space is not possible. This proposed driver, therefore, implements the problematic interfaces directly in the Linux kernel. This driver was presented at Linux Plumbers Conference 2023. For those further interested in the history of synchronization in Wine and past attempts to solve this problem in user space, a recording of the presentation can be viewed here: https://www.youtube.com/watch?v=NjU4nyWyhU8 == Performance == The performance measurements described below are copied from earlier versions of the patch set. While some of the code has changed, I do not currently anticipate that it has changed drastically enough to affect those measurements. The gain in performance varies wildly depending on the application in question and the user's hardware. For some games NT synchronization is not a bottleneck and no change can be observed, but for others frame rate improvements of 50 to 150 percent are not atypical. The following table lists frame rate measurements from a variety of games on a variety of hardware, taken by users Dmitry Skvortsov, FuzzyQuils, OnMars, and myself: Game Upstream ntsync improvement =========================================================================== Anger Foot 69 99 43% Call of Juarez 99.8 224.1 125% Dirt 3 110.6 860.7 678% Forza Horizon 5 108 160 48% Lara Croft: Temple of Osiris 141 326 131% Metro 2033 164.4 199.2 21% Resident Evil 2 26 77 196% The Crew 26 51 96% Tiny Tina's Wonderlands 130 360 177% Total War Saga: Troy 109 146 34% =========================================================================== == Patches == The intended semantics of the patches are broadly intended to match those of the corresponding Windows functions. For those not already familiar with the Windows functions (or their undocumented behaviour), patch 27/28 provides a detailed specification, and individual patches also include a brief description of the API they are implementing. The patches making use of this driver in Wine can be retrieved or browsed here: https://repo.or.cz/wine/zf.git/shortlog/refs/heads/ntsync5 == Previous versions == Changes from v4: * Rework wait-all locking code to avoid taking more than one spinlock at a time, and also to fix a race where the wait-all lock would not be not correctly taken. The new locking mechanism involves taking a simple spinlock for normal "any" waits, and taking a device-wide mutex for "all" waits or when locking any object that is involved in an "all" wait. The mechanism was written by Peter Zijlstra. * Try to reword or clarify various parts of the documentation (patch 27), per Peter Zijlstra. * I did not rename NTSYNC_IOC_SEM_POST to RELEASE (like NT) although this was suggested by Peter Zijlstra, mostly because it's not clear to me that renaming an already committed ioctl would be fine. The API committed isn't actually usable yet, though, so if altering it would be fine on those grounds, I can revise this series to rename the function accordingly. * Similarly, I did not change the create ioctls to return the fd directly, although this was suggested and would be a bit simpler and cleaner, because NTSYNC_IOC_CREATE_SEM already exists upstream and returns the fd through a struct. I can make this change in the next revision if that'd be preferable. I also still would appreciate a clarification on the advice in [1]. [1] https://docs.kernel.org/driver-api/ioctl.html#return-code * Link to v4: https://lore.kernel.org/lkml/20240416010837.333694-1-zfigura@codeweavers.co… * Link to v3: https://lore.kernel.org/lkml/20240329000621.148791-1-zfigura@codeweavers.co… * Link to v2: https://lore.kernel.org/lkml/20240219223833.95710-1-zfigura@codeweavers.com/ * Link to v1: https://lore.kernel.org/lkml/20240214233645.9273-1-zfigura@codeweavers.com/ * Link to RFC v2: https://lore.kernel.org/lkml/20240131021356.10322-1-zfigura@codeweavers.com/ * Link to RFC v1: https://lore.kernel.org/lkml/20240124004028.16826-1-zfigura@codeweavers.com/ Elizabeth Figura (28): ntsync: Introduce NTSYNC_IOC_WAIT_ANY. ntsync: Introduce NTSYNC_IOC_WAIT_ALL. ntsync: Introduce NTSYNC_IOC_CREATE_MUTEX. ntsync: Introduce NTSYNC_IOC_MUTEX_UNLOCK. ntsync: Introduce NTSYNC_IOC_MUTEX_KILL. ntsync: Introduce NTSYNC_IOC_CREATE_EVENT. ntsync: Introduce NTSYNC_IOC_EVENT_SET. ntsync: Introduce NTSYNC_IOC_EVENT_RESET. ntsync: Introduce NTSYNC_IOC_EVENT_PULSE. ntsync: Introduce NTSYNC_IOC_SEM_READ. ntsync: Introduce NTSYNC_IOC_MUTEX_READ. ntsync: Introduce NTSYNC_IOC_EVENT_READ. ntsync: Introduce alertable waits. selftests: ntsync: Add some tests for semaphore state. selftests: ntsync: Add some tests for mutex state. selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ANY. selftests: ntsync: Add some tests for NTSYNC_IOC_WAIT_ALL. selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ANY. selftests: ntsync: Add some tests for wakeup signaling with WINESYNC_IOC_WAIT_ALL. selftests: ntsync: Add some tests for manual-reset event state. selftests: ntsync: Add some tests for auto-reset event state. selftests: ntsync: Add some tests for wakeup signaling with events. selftests: ntsync: Add tests for alertable waits. selftests: ntsync: Add some tests for wakeup signaling via alerts. selftests: ntsync: Add a stress test for contended waits. maintainers: Add an entry for ntsync. docs: ntsync: Add documentation for the ntsync uAPI. ntsync: No longer depend on BROKEN. Documentation/userspace-api/index.rst | 1 + Documentation/userspace-api/ntsync.rst | 398 +++++ MAINTAINERS | 9 + drivers/misc/Kconfig | 1 - drivers/misc/ntsync.c | 989 +++++++++++- include/uapi/linux/ntsync.h | 39 + tools/testing/selftests/Makefile | 1 + .../selftests/drivers/ntsync/.gitignore | 1 + .../testing/selftests/drivers/ntsync/Makefile | 7 + tools/testing/selftests/drivers/ntsync/config | 1 + .../testing/selftests/drivers/ntsync/ntsync.c | 1407 +++++++++++++++++ 11 files changed, 2850 insertions(+), 4 deletions(-) create mode 100644 Documentation/userspace-api/ntsync.rst create mode 100644 tools/testing/selftests/drivers/ntsync/.gitignore create mode 100644 tools/testing/selftests/drivers/ntsync/Makefile create mode 100644 tools/testing/selftests/drivers/ntsync/config create mode 100644 tools/testing/selftests/drivers/ntsync/ntsync.c base-commit: f5b335dc025cfee90957efa90dc72fada0d5abb4 -- 2.43.0

3 weeks

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[PATCH v6 00/16] selftests/resctrl: resctrl_val() related cleanups & improvements

by Ilpo Järvinen

Hi all, This series does a number of cleanups into resctrl_val() and generalizes it by removing test name specific handling from the function. v6: - Adjust closing/rollback of the IMC perf - Move the comment in measure_vals() to function level - Capitalize MBM - binded to -> bound to - Language tweak into kerneldoc - Removed stale paragraph from commit message v5: - Open mem bw file only once and use rewind(). - Add \n to mem bw file read to allow reading fresh values from the file. - Return 0 if create_grp() is given NULL grp_name (matches the original behavior). Mention this in function's kerneldoc. - Cast pid_t to int before printing with %d. - Caps/typo fixes to kerneldoc and commit messages. - Use imperative tone in commit messages and improve them based on points that came up during review. v4: - Merged close fix into IMC READ+WRITE rework patch - Add loop to reset imc_counters_config fds to -1 to be able know which need closing - Introduce perf_close_imc_mem_bw() to close fds - Open resctrl mem bw file (twice) beforehand to avoid opening it during the test - Remove MBM .mongrp setup - Remove mongrp from CMT test v3: - Rename init functions to <testname>_init() - Replace for loops with READ+WRITE statements for clarity - Don't drop Return: entry from perf_open_imc_mem_bw() func comment - New patch: Fix closing of IMC fds in case of error - New patch: Make "bandwidth" consistent in comments & prints - New patch: Simplify mem bandwidth file code - Remove wrong comment - Changed grp_name check to return -1 on fail (internal sanity check) v2: - Resolved conflicts with kselftest/next - Spaces -> tabs correction Ilpo Järvinen (16): selftests/resctrl: Fix closing IMC fds on error and open-code R+W instead of loops selftests/resctrl: Calculate resctrl FS derived mem bw over sleep(1) only selftests/resctrl: Make "bandwidth" consistent in comments & prints selftests/resctrl: Consolidate get_domain_id() into resctrl_val() selftests/resctrl: Use correct type for pids selftests/resctrl: Cleanup bm_pid and ppid usage & limit scope selftests/resctrl: Rename measure_vals() to measure_mem_bw_vals() & document selftests/resctrl: Simplify mem bandwidth file code for MBA & MBM tests selftests/resctrl: Add ->measure() callback to resctrl_val_param selftests/resctrl: Add ->init() callback into resctrl_val_param selftests/resctrl: Simplify bandwidth report type handling selftests/resctrl: Make some strings passed to resctrlfs functions const selftests/resctrl: Convert ctrlgrp & mongrp to pointers selftests/resctrl: Remove mongrp from MBA test selftests/resctrl: Remove mongrp from CMT test selftests/resctrl: Remove test name comparing from write_bm_pid_to_resctrl() tools/testing/selftests/resctrl/cache.c | 10 +- tools/testing/selftests/resctrl/cat_test.c | 5 +- tools/testing/selftests/resctrl/cmt_test.c | 22 +- tools/testing/selftests/resctrl/mba_test.c | 26 +- tools/testing/selftests/resctrl/mbm_test.c | 26 +- tools/testing/selftests/resctrl/resctrl.h | 49 ++- tools/testing/selftests/resctrl/resctrl_val.c | 371 ++++++++---------- tools/testing/selftests/resctrl/resctrlfs.c | 67 ++-- 8 files changed, 291 insertions(+), 285 deletions(-) -- 2.39.2

3 weeks

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[PATCH] MAINTAINERS: Add selftests/x86 entry

by Muhammad Usama Anjum

There are no maintainers specified for tools/testing/selftests/x86. Shuah has mentioned [1] that the patches should go through x86 tree or in special cases directly to Shuah's tree after getting ack-ed from x86 maintainers. Different people have been confused when sending patches as correct maintainers aren't found by get_maintainer.pl script. Fix this by adding entry to MAINTAINERS file. [1] https://lore.kernel.org/all/90dc0dfc-4c67-4ea1-b705-0585d6e2ec47@linuxfound… Signed-off-by: Muhammad Usama Anjum <usama.anjum(a)collabora.com> --- MAINTAINERS | 1 + 1 file changed, 1 insertion(+) diff --git a/MAINTAINERS b/MAINTAINERS index 523d84b2d6139..f3a17e5d954a3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -24378,6 +24378,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/core F: Documentation/arch/x86/ F: Documentation/devicetree/bindings/x86/ F: arch/x86/ +F: tools/testing/selftests/x86 X86 ENTRY CODE M: Andy Lutomirski <luto(a)kernel.org> -- 2.39.2

3 weeks

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[PATCH 0/4] selftest: x86: conform tests to TAP format output

by Muhammad Usama Anjum

In this series, 4 tests are being conformed to TAP. Muhammad Usama Anjum (4): selftests: x86: check_initial_reg_state: conform test to TAP format output selftests: x86: corrupt_xstate_header: conform test to TAP format output selftests: fsgsbase_restore: conform test to TAP format output selftests: entry_from_vm86: conform test to TAP format output .../selftests/x86/check_initial_reg_state.c | 24 ++-- .../selftests/x86/corrupt_xstate_header.c | 30 +++-- tools/testing/selftests/x86/entry_from_vm86.c | 109 ++++++++-------- .../testing/selftests/x86/fsgsbase_restore.c | 117 +++++++++--------- 4 files changed, 139 insertions(+), 141 deletions(-) -- 2.39.2

3 weeks

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[PATCH] selftests: net: Add on/off checks for network interface non fixed features

by Abhinav Jain

This patch addresses the present TODO in the file. I have tested it manually on my system and added relevant filtering to ensure that the correct feature list is being checked. Signed-off-by: Abhinav Jain <jain.abhinav177(a)gmail.com> --- tools/testing/selftests/net/netdevice.sh | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/netdevice.sh b/tools/testing/selftests/net/netdevice.sh index e3afcb424710..cbe2573c3827 100755 --- a/tools/testing/selftests/net/netdevice.sh +++ b/tools/testing/selftests/net/netdevice.sh @@ -117,14 +117,31 @@ kci_netdev_ethtool() return 1 fi - ethtool -k "$netdev" > "$TMP_ETHTOOL_FEATURES" + ethtool -k "$netdev" | tail -n +2 > "$TMP_ETHTOOL_FEATURES" if [ $? -ne 0 ];then echo "FAIL: $netdev: ethtool list features" rm "$TMP_ETHTOOL_FEATURES" return 1 fi echo "PASS: $netdev: ethtool list features" - #TODO for each non fixed features, try to turn them on/off + + for feature in $(grep -v fixed "$TMP_ETHTOOL_FEATURES" | \ + awk '{print $1}' | sed 's/://'); do + ethtool --offload "$netdev" "$feature" off + if [ $? -eq 0 ]; then + echo "PASS: $netdev: Turned off feature: $feature" + else + echo "FAIL: $netdev: Failed to turn off feature: $feature" + fi + + ethtool --offload "$netdev" "$feature" on + if [ $? -eq 0 ]; then + echo "PASS: $netdev: Turned on feature: $feature" + else + echo "FAIL: $netdev: Failed to turn on feature: $feature" + fi + done + rm "$TMP_ETHTOOL_FEATURES" kci_netdev_ethtool_test 74 'dump' "ethtool -d $netdev" -- 2.34.1

3 weeks, 1 day

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[PATCH v3] selftests/mm: use asm volatile to not optimize mmap read variable

by Pankaj Raghav (Samsung)

From: Pankaj Raghav <p.raghav(a)samsung.com> create_pagecache_thp_and_fd() in split_huge_page_test.c used the variable dummy to perform mmap read. However, this test was skipped even on XFS which has large folio support. The issue was compiler (gcc 13.2.0) was optimizing out the dummy variable, therefore, not creating huge page in the page cache. Use asm volatile() trick to force the compiler not to optimize out the loop where we read from the mmaped addr. This is similar to what is being done in other tests (cow.c, etc) As the variable is now used in the asm statement, remove the unused attribute. Signed-off-by: Pankaj Raghav <p.raghav(a)samsung.com> --- Changes since v2: - Use the asm volatile trick to force the compiler to not optimize the read into dummy variable. (David) 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 d3c7f5fb3e7b..e5e8dafc9d94 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -300,7 +300,7 @@ int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, int *fd, char **addr) { size_t i; - int __attribute__((unused)) dummy = 0; + int dummy = 0; srand(time(NULL)); @@ -341,6 +341,7 @@ int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, int *fd, for (size_t i = 0; i < fd_size; i++) dummy += *(*addr + i); + asm volatile("" : "+r" (dummy)); if (!check_huge_file(*addr, fd_size / pmd_pagesize, pmd_pagesize)) { ksft_print_msg("No large pagecache folio generated, please provide a filesystem supporting large folio\n"); base-commit: d97496ca23a2d4ee80b7302849404859d9058bcd -- 2.44.1

3 weeks, 2 days

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[PATCH HID v2 00/16] HID: convert HID-BPF into using bpf_struct_ops

by Benjamin Tissoires

The purpose of this series is to rethink how HID-BPF is invoked. Currently it implies a jmp table, a prog fd bpf_map, a preloaded tracing bpf program and a lot of manual work for handling the bpf program lifetime and addition/removal. OTOH, bpf_struct_ops take care of most of the bpf handling leaving us with a simple list of ops pointers, and we can directly call the struct_ops program from the kernel as a regular function. The net gain right now is in term of code simplicity and lines of code removal (though is an API breakage), but udev-hid-bpf is able to handle such breakages. In the near future, we will be able to extend the HID-BPF struct_ops with entrypoints for hid_hw_raw_request() and hid_hw_output_report(), allowing for covering all of the initial use cases: - firewalling a HID device - fixing all of the HID device interactions (not just device events as it is right now). The matching user-space loader (udev-hid-bpf) MR is at https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/86 I'll put it out of draft once this is merged. Cheers, Benjamin Signed-off-by: Benjamin Tissoires <bentiss(a)kernel.org> --- Changes in v2: - drop HID_BPF_FLAGS enum and use BPF_F_BEFORE instead - fix .init_members to not open code member->offset - allow struct hid_device to be writeable from HID-BPF for its name, uniq and phys - Link to v1: https://lore.kernel.org/r/20240528-hid_bpf_struct_ops-v1-0-8c6663df27d8@ker… --- Benjamin Tissoires (16): HID: rename struct hid_bpf_ops into hid_ops HID: bpf: add hid_get/put_device() helpers HID: bpf: implement HID-BPF through bpf_struct_ops selftests/hid: convert the hid_bpf selftests with struct_ops HID: samples: convert the 2 HID-BPF samples into struct_ops HID: bpf: add defines for HID-BPF SEC in in-tree bpf fixes HID: bpf: convert in-tree fixes into struct_ops HID: bpf: remove tracing HID-BPF capability selftests/hid: add subprog call test Documentation: HID: amend HID-BPF for struct_ops Documentation: HID: add a small blurb on udev-hid-bpf HID: bpf: Artist24: remove unused variable HID: bpf: error on warnings when compiling bpf objects bpf: allow bpf helpers to be used into HID-BPF struct_ops HID: bpf: rework hid_bpf_ops_btf_struct_access HID: bpf: make part of struct hid_device writable Documentation/hid/hid-bpf.rst | 173 ++++--- drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/entrypoints/Makefile | 93 ---- drivers/hid/bpf/entrypoints/README | 4 - drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 25 - drivers/hid/bpf/entrypoints/entrypoints.lskel.h | 248 --------- drivers/hid/bpf/hid_bpf_dispatch.c | 266 +++------- drivers/hid/bpf/hid_bpf_dispatch.h | 12 +- drivers/hid/bpf/hid_bpf_jmp_table.c | 565 --------------------- drivers/hid/bpf/hid_bpf_struct_ops.c | 298 +++++++++++ drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c | 9 +- drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c | 6 +- drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c | 9 +- .../hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c | 6 +- drivers/hid/bpf/progs/Makefile | 2 +- .../hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c | 6 +- drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c | 6 +- drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 10 +- drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c | 24 +- drivers/hid/bpf/progs/hid_bpf.h | 5 + drivers/hid/hid-core.c | 6 +- include/linux/hid_bpf.h | 125 ++--- samples/hid/Makefile | 5 +- samples/hid/hid_bpf_attach.bpf.c | 18 - samples/hid/hid_bpf_attach.h | 14 - samples/hid/hid_mouse.bpf.c | 26 +- samples/hid/hid_mouse.c | 39 +- samples/hid/hid_surface_dial.bpf.c | 10 +- samples/hid/hid_surface_dial.c | 53 +- tools/testing/selftests/hid/hid_bpf.c | 100 +++- tools/testing/selftests/hid/progs/hid.c | 100 +++- .../testing/selftests/hid/progs/hid_bpf_helpers.h | 19 +- 32 files changed, 805 insertions(+), 1479 deletions(-) --- base-commit: 70ec81c2e2b4005465ad0d042e90b36087c36104 change-id: 20240513-hid_bpf_struct_ops-e3212a224555 Best regards, -- Benjamin Tissoires <bentiss(a)kernel.org>

3 weeks, 2 days

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[PATCH 07/10] selftests/pidfd: Fix wrong expectation

by Okan Tümüklü

From: Mickaël Salaün <mic(a)digikod.net> Replace a wrong EXPECT_GT(self->child_pid_exited, 0) with EXPECT_GE(), which will be actually tested on the parent and child sides with a following commit. Cc: Shuah Khan <skhan(a)linuxfoundation.org> Reviewed-by: Kees Cook <keescook(a)chromium.org> Reviewed-by: Christian Brauner <brauner(a)kernel.org> Link: https://lore.kernel.org/r/20240511171445.904356-8-mic@digikod.net Signed-off-by: Mickaël Salaün <mic(a)digikod.net> --- tools/testing/selftests/pidfd/pidfd_setns_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/pidfd/pidfd_setns_test.c b/tools/testing/selftests/pidfd/pidfd_setns_test.c index 6e2f2cd400ca..47746b0c6acd 100644 --- a/tools/testing/selftests/pidfd/pidfd_setns_test.c +++ b/tools/testing/selftests/pidfd/pidfd_setns_test.c @@ -158,7 +158,7 @@ FIXTURE_SETUP(current_nsset) /* Create task that exits right away. */ self->child_pid_exited = create_child(&self->child_pidfd_exited, CLONE_NEWUSER | CLONE_NEWNET); - EXPECT_GT(self->child_pid_exited, 0); + EXPECT_GE(self->child_pid_exited, 0); if (self->child_pid_exited == 0) _exit(EXIT_SUCCESS); -- 2.39.2

3 weeks, 2 days

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[PATCH 0/8] selftests: x86: build suite with clang

by Muhammad Usama Anjum

This series fixes build errors found by clang to allow the x86 suite to get built with the clang. Unfortunately, there is one bug [1] in the clang becuase of which extended asm isn't handled correctly by it and build fails for sysret_rip.c. Hence even after this series the build of this test would fail with clang. Should we disable this test for now when clang is used until the bug is fixed in clang? Not sure. Any opinions? [1] https://github.com/llvm/llvm-project/issues/53728 Muhammad Usama Anjum (8): selftests: x86: Remove dependence of headers file selftests: x86: check_initial_reg_state: remove -no-pie while using -static selftests: x86: test_vsyscall: remove unused function selftests: x86: fsgsbase_restore: fix asm directive from =rm to =r selftests: x86: syscall_arg_fault_32: remove unused variable selftests: x86: test_FISTTP: use fisttps instead of ambigous fisttp selftests: x86: fsgsbase: Remove unused function and variable selftests: x86: amx: Remove unused functions tools/testing/selftests/x86/Makefile | 9 +++++---- tools/testing/selftests/x86/amx.c | 16 ---------------- tools/testing/selftests/x86/fsgsbase.c | 6 ------ tools/testing/selftests/x86/fsgsbase_restore.c | 2 +- tools/testing/selftests/x86/syscall_arg_fault.c | 1 - tools/testing/selftests/x86/test_FISTTP.c | 8 ++++---- tools/testing/selftests/x86/test_vsyscall.c | 5 ----- 7 files changed, 10 insertions(+), 37 deletions(-) -- 2.39.2

3 weeks, 2 days

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[PATCH v4] selftest: mm: Test if hugepage does not get leaked during __bio_release_pages()

by Donet Tom

Commit 1b151e2435fc ("block: Remove special-casing of compound pages") caused a change in behaviour when releasing the pages if the buffer does not start at the beginning of the page. This was because the calculation of the number of pages to release was incorrect. This was fixed by commit 38b43539d64b ("block: Fix page refcounts for unaligned buffers in __bio_release_pages()"). We pin the user buffer during direct I/O writes. If this buffer is a hugepage, bio_release_page() will unpin it and decrement all references and pin counts at ->bi_end_io. However, if any references to the hugepage remain post-I/O, the hugepage will not be freed upon unmap, leading to a memory leak. This patch verifies that a hugepage, used as a user buffer for DIO operations, is correctly freed upon unmapping, regardless of whether the offsets are aligned or unaligned w.r.t page boundary. Test Result Fail Scenario (Without the fix) -------------------------------------------------------- []# ./hugetlb_dio TAP version 13 1..4 No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 1 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 2 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 3 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 6 not ok 4 : Huge pages not freed! Totals: pass:3 fail:1 xfail:0 xpass:0 skip:0 error:0 Test Result PASS Scenario (With the fix) --------------------------------------------------------- []#./hugetlb_dio TAP version 13 1..4 No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 1 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 2 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 3 : Huge pages freed successfully ! No. Free pages before allocation : 7 No. Free pages after munmap : 7 ok 4 : Huge pages freed successfully ! Totals: pass:4 fail:0 xfail:0 xpass:0 skip:0 error:0 V4: - Added this test to run_vmtests.sh. V3: - Fixed the build error when it is compiled with _FORTIFY_SOURCE. V2: - Addressed all review commets from Muhammad Usama Anjum https://lore.kernel.org/all/20240604132801.23377-1-donettom@linux.ibm.com/ V1: https://lore.kernel.org/all/20240523063905.3173-1-donettom@linux.ibm.com/#t Signed-off-by: Donet Tom <donettom(a)linux.ibm.com> Co-developed-by: Ritesh Harjani (IBM) <ritesh.list(a)gmail.com> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list(a)gmail.com> Reviewed-by: Muhammad Usama Anjum <usama.anjum(a)collabora.com> --- tools/testing/selftests/mm/Makefile | 1 + tools/testing/selftests/mm/hugetlb_dio.c | 118 ++++++++++++++++++++++ tools/testing/selftests/mm/run_vmtests.sh | 1 + 3 files changed, 120 insertions(+) create mode 100644 tools/testing/selftests/mm/hugetlb_dio.c diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index 3b49bc3d0a3b..a1748a4c7df1 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -73,6 +73,7 @@ TEST_GEN_FILES += ksm_functional_tests TEST_GEN_FILES += mdwe_test TEST_GEN_FILES += hugetlb_fault_after_madv TEST_GEN_FILES += hugetlb_madv_vs_map +TEST_GEN_FILES += hugetlb_dio ifneq ($(ARCH),arm64) TEST_GEN_FILES += soft-dirty diff --git a/tools/testing/selftests/mm/hugetlb_dio.c b/tools/testing/selftests/mm/hugetlb_dio.c new file mode 100644 index 000000000000..986f3b6c7f7b --- /dev/null +++ b/tools/testing/selftests/mm/hugetlb_dio.c @@ -0,0 +1,118 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This program tests for hugepage leaks after DIO writes to a file using a + * hugepage as the user buffer. During DIO, the user buffer is pinned and + * should be properly unpinned upon completion. This patch verifies that the + * kernel correctly unpins the buffer at DIO completion for both aligned and + * unaligned user buffer offsets (w.r.t page boundary), ensuring the hugepage + * is freed upon unmapping. + */ + +#define _GNU_SOURCE +#include <stdio.h> +#include <sys/stat.h> +#include <stdlib.h> +#include <fcntl.h> +#include <stdint.h> +#include <unistd.h> +#include <string.h> +#include <sys/mman.h> +#include "vm_util.h" +#include "../kselftest.h" + +void run_dio_using_hugetlb(unsigned int start_off, unsigned int end_off) +{ + int fd; + char *buffer = NULL; + char *orig_buffer = NULL; + size_t h_pagesize = 0; + size_t writesize; + int free_hpage_b = 0; + int free_hpage_a = 0; + const int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB; + const int mmap_prot = PROT_READ | PROT_WRITE; + + writesize = end_off - start_off; + + /* Get the default huge page size */ + h_pagesize = default_huge_page_size(); + if (!h_pagesize) + ksft_exit_fail_msg("Unable to determine huge page size\n"); + + /* Open the file to DIO */ + fd = open("/tmp", O_TMPFILE | O_RDWR | O_DIRECT, 0664); + if (fd < 0) + ksft_exit_fail_perror("Error opening file\n"); + + /* Get the free huge pages before allocation */ + free_hpage_b = get_free_hugepages(); + if (free_hpage_b == 0) { + close(fd); + ksft_exit_skip("No free hugepage, exiting!\n"); + } + + /* Allocate a hugetlb page */ + orig_buffer = mmap(NULL, h_pagesize, mmap_prot, mmap_flags, -1, 0); + if (orig_buffer == MAP_FAILED) { + close(fd); + ksft_exit_fail_perror("Error mapping memory\n"); + } + buffer = orig_buffer; + buffer += start_off; + + memset(buffer, 'A', writesize); + + /* Write the buffer to the file */ + if (write(fd, buffer, writesize) != (writesize)) { + munmap(orig_buffer, h_pagesize); + close(fd); + ksft_exit_fail_perror("Error writing to file\n"); + } + + /* unmap the huge page */ + munmap(orig_buffer, h_pagesize); + close(fd); + + /* Get the free huge pages after unmap*/ + free_hpage_a = get_free_hugepages(); + + /* + * If the no. of free hugepages before allocation and after unmap does + * not match - that means there could still be a page which is pinned. + */ + if (free_hpage_a != free_hpage_b) { + ksft_print_msg("No. Free pages before allocation : %d\n", free_hpage_b); + ksft_print_msg("No. Free pages after munmap : %d\n", free_hpage_a); + ksft_test_result_fail(": Huge pages not freed!\n"); + } else { + ksft_print_msg("No. Free pages before allocation : %d\n", free_hpage_b); + ksft_print_msg("No. Free pages after munmap : %d\n", free_hpage_a); + ksft_test_result_pass(": Huge pages freed successfully !\n"); + } +} + +int main(void) +{ + size_t pagesize = 0; + + ksft_print_header(); + ksft_set_plan(4); + + /* Get base page size */ + pagesize = psize(); + + /* start and end is aligned to pagesize */ + run_dio_using_hugetlb(0, (pagesize * 3)); + + /* start is aligned but end is not aligned */ + run_dio_using_hugetlb(0, (pagesize * 3) - (pagesize / 2)); + + /* start is unaligned and end is aligned */ + run_dio_using_hugetlb(pagesize / 2, (pagesize * 3)); + + /* both start and end are unaligned */ + run_dio_using_hugetlb(pagesize / 2, (pagesize * 3) + (pagesize / 2)); + + ksft_finished(); +} + diff --git a/tools/testing/selftests/mm/run_vmtests.sh b/tools/testing/selftests/mm/run_vmtests.sh index 3157204b9047..5698d519170d 100755 --- a/tools/testing/selftests/mm/run_vmtests.sh +++ b/tools/testing/selftests/mm/run_vmtests.sh @@ -265,6 +265,7 @@ CATEGORY="hugetlb" run_test ./map_hugetlb CATEGORY="hugetlb" run_test ./hugepage-mremap CATEGORY="hugetlb" run_test ./hugepage-vmemmap CATEGORY="hugetlb" run_test ./hugetlb-madvise +CATEGORY="hugetlb" run_test ./hugetlb_dio nr_hugepages_tmp=$(cat /proc/sys/vm/nr_hugepages) # For this test, we need one and just one huge page -- 2.43.0

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Linux-kselftest-mirror June 2024