December 2025 - Linux-kselftest-mirror

[PATCH] kunit: reduce stack usage in kunit_run_tests()

by Arnd Bergmann

From: Arnd Bergmann <arnd(a)arndb.de> Some of the recent changes to the kunit framework caused the stack usage for kunit_run_tests() to grow higher than most other kernel functions, which triggers a warning when CONFIG_FRAME_WARN is set to a relatively low value: lib/kunit/test.c: In function 'kunit_run_tests': lib/kunit/test.c:801:1: error: the frame size of 1312 bytes is larger than 1280 bytes [-Werror=frame-larger-than=] Split out the inner loop into a separate function to ensure that each function remains under the limit, and pass the kunit_result_stats structures by reference to avoid excessive copies. Signed-off-by: Arnd Bergmann <arnd(a)arndb.de> --- Sending it now as I ran into the build failure while testing 6.18. I only build-tested this, so please test it properly before applying. --- lib/kunit/test.c | 221 ++++++++++++++++++++++++----------------------- 1 file changed, 115 insertions(+), 106 deletions(-) diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 62eb529824c6..c5fce199d880 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -94,7 +94,7 @@ struct kunit_result_stats { unsigned long total; }; -static bool kunit_should_print_stats(struct kunit_result_stats stats) +static bool kunit_should_print_stats(struct kunit_result_stats *stats) { if (kunit_stats_enabled == 0) return false; @@ -102,11 +102,11 @@ static bool kunit_should_print_stats(struct kunit_result_stats stats) if (kunit_stats_enabled == 2) return true; - return (stats.total > 1); + return (stats->total > 1); } static void kunit_print_test_stats(struct kunit *test, - struct kunit_result_stats stats) + struct kunit_result_stats *stats) { if (!kunit_should_print_stats(stats)) return; @@ -115,10 +115,10 @@ static void kunit_print_test_stats(struct kunit *test, KUNIT_SUBTEST_INDENT "# %s: pass:%lu fail:%lu skip:%lu total:%lu", test->name, - stats.passed, - stats.failed, - stats.skipped, - stats.total); + stats->passed, + stats->failed, + stats->skipped, + stats->total); } /* Append formatted message to log. */ @@ -600,26 +600,26 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite, } static void kunit_print_suite_stats(struct kunit_suite *suite, - struct kunit_result_stats suite_stats, - struct kunit_result_stats param_stats) + struct kunit_result_stats *suite_stats, + struct kunit_result_stats *param_stats) { if (kunit_should_print_stats(suite_stats)) { kunit_log(KERN_INFO, suite, "# %s: pass:%lu fail:%lu skip:%lu total:%lu", suite->name, - suite_stats.passed, - suite_stats.failed, - suite_stats.skipped, - suite_stats.total); + suite_stats->passed, + suite_stats->failed, + suite_stats->skipped, + suite_stats->total); } if (kunit_should_print_stats(param_stats)) { kunit_log(KERN_INFO, suite, "# Totals: pass:%lu fail:%lu skip:%lu total:%lu", - param_stats.passed, - param_stats.failed, - param_stats.skipped, - param_stats.total); + param_stats->passed, + param_stats->failed, + param_stats->skipped, + param_stats->total); } } @@ -681,13 +681,106 @@ static void kunit_init_parent_param_test(struct kunit_case *test_case, struct ku } } -int kunit_run_tests(struct kunit_suite *suite) +static int kunit_run_one_test(struct kunit_suite *suite, struct kunit_case *test_case, + struct kunit_result_stats *suite_stats, + struct kunit_result_stats *total_stats) { + struct kunit test = { .param_value = NULL, .param_index = 0 }; + struct kunit_result_stats param_stats = { 0 }; char param_desc[KUNIT_PARAM_DESC_SIZE]; + const void *curr_param; + + kunit_init_test(&test, test_case->name, test_case->log); + if (test_case->status == KUNIT_SKIPPED) { + /* Test marked as skip */ + test.status = KUNIT_SKIPPED; + kunit_update_stats(&param_stats, test.status); + } else if (!test_case->generate_params) { + /* Non-parameterised test. */ + test_case->status = KUNIT_SKIPPED; + kunit_run_case_catch_errors(suite, test_case, &test); + kunit_update_stats(&param_stats, test.status); + } else { + kunit_init_parent_param_test(test_case, &test); + if (test_case->status == KUNIT_FAILURE) { + kunit_update_stats(&param_stats, test.status); + goto test_case_end; + } + /* Get initial param. */ + param_desc[0] = '\0'; + /* TODO: Make generate_params try-catch */ + curr_param = test_case->generate_params(&test, NULL, param_desc); + test_case->status = KUNIT_SKIPPED; + kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT + "KTAP version 1\n"); + kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT + "# Subtest: %s", test_case->name); + if (test.params_array.params && + test_case->generate_params == kunit_array_gen_params) { + kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT + KUNIT_SUBTEST_INDENT "1..%zd\n", + test.params_array.num_params); + } + + while (curr_param) { + struct kunit param_test = { + .param_value = curr_param, + .param_index = ++test.param_index, + .parent = &test, + }; + kunit_init_test(&param_test, test_case->name, NULL); + param_test.log = test_case->log; + kunit_run_case_catch_errors(suite, test_case, &param_test); + + if (param_desc[0] == '\0') { + snprintf(param_desc, sizeof(param_desc), + "param-%d", param_test.param_index); + } + + kunit_print_ok_not_ok(&param_test, KUNIT_LEVEL_CASE_PARAM, + param_test.status, + param_test.param_index, + param_desc, + param_test.status_comment); + + kunit_update_stats(&param_stats, param_test.status); + + /* Get next param. */ + param_desc[0] = '\0'; + curr_param = test_case->generate_params(&test, curr_param, + param_desc); + } + /* + * TODO: Put into a try catch. Since we don't need suite->exit + * for it we can't reuse kunit_try_run_cleanup for this yet. + */ + if (test_case->param_exit) + test_case->param_exit(&test); + /* TODO: Put this kunit_cleanup into a try-catch. */ + kunit_cleanup(&test); + } +test_case_end: + kunit_print_attr((void *)test_case, true, KUNIT_LEVEL_CASE); + + kunit_print_test_stats(&test, &param_stats); + + kunit_print_ok_not_ok(&test, KUNIT_LEVEL_CASE, test_case->status, + kunit_test_case_num(suite, test_case), + test_case->name, + test.status_comment); + + kunit_update_stats(suite_stats, test_case->status); + kunit_accumulate_stats(total_stats, param_stats); + + return 0; +} + + +int kunit_run_tests(struct kunit_suite *suite) +{ struct kunit_case *test_case; struct kunit_result_stats suite_stats = { 0 }; struct kunit_result_stats total_stats = { 0 }; - const void *curr_param; /* Taint the kernel so we know we've run tests. */ add_taint(TAINT_TEST, LOCKDEP_STILL_OK); @@ -703,97 +796,13 @@ int kunit_run_tests(struct kunit_suite *suite) kunit_print_suite_start(suite); - kunit_suite_for_each_test_case(suite, test_case) { - struct kunit test = { .param_value = NULL, .param_index = 0 }; - struct kunit_result_stats param_stats = { 0 }; - - kunit_init_test(&test, test_case->name, test_case->log); - if (test_case->status == KUNIT_SKIPPED) { - /* Test marked as skip */ - test.status = KUNIT_SKIPPED; - kunit_update_stats(&param_stats, test.status); - } else if (!test_case->generate_params) { - /* Non-parameterised test. */ - test_case->status = KUNIT_SKIPPED; - kunit_run_case_catch_errors(suite, test_case, &test); - kunit_update_stats(&param_stats, test.status); - } else { - kunit_init_parent_param_test(test_case, &test); - if (test_case->status == KUNIT_FAILURE) { - kunit_update_stats(&param_stats, test.status); - goto test_case_end; - } - /* Get initial param. */ - param_desc[0] = '\0'; - /* TODO: Make generate_params try-catch */ - curr_param = test_case->generate_params(&test, NULL, param_desc); - test_case->status = KUNIT_SKIPPED; - kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT - "KTAP version 1\n"); - kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT - "# Subtest: %s", test_case->name); - if (test.params_array.params && - test_case->generate_params == kunit_array_gen_params) { - kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT - KUNIT_SUBTEST_INDENT "1..%zd\n", - test.params_array.num_params); - } - - while (curr_param) { - struct kunit param_test = { - .param_value = curr_param, - .param_index = ++test.param_index, - .parent = &test, - }; - kunit_init_test(&param_test, test_case->name, NULL); - param_test.log = test_case->log; - kunit_run_case_catch_errors(suite, test_case, &param_test); - - if (param_desc[0] == '\0') { - snprintf(param_desc, sizeof(param_desc), - "param-%d", param_test.param_index); - } - - kunit_print_ok_not_ok(&param_test, KUNIT_LEVEL_CASE_PARAM, - param_test.status, - param_test.param_index, - param_desc, - param_test.status_comment); - - kunit_update_stats(&param_stats, param_test.status); - - /* Get next param. */ - param_desc[0] = '\0'; - curr_param = test_case->generate_params(&test, curr_param, - param_desc); - } - /* - * TODO: Put into a try catch. Since we don't need suite->exit - * for it we can't reuse kunit_try_run_cleanup for this yet. - */ - if (test_case->param_exit) - test_case->param_exit(&test); - /* TODO: Put this kunit_cleanup into a try-catch. */ - kunit_cleanup(&test); - } -test_case_end: - kunit_print_attr((void *)test_case, true, KUNIT_LEVEL_CASE); - - kunit_print_test_stats(&test, param_stats); - - kunit_print_ok_not_ok(&test, KUNIT_LEVEL_CASE, test_case->status, - kunit_test_case_num(suite, test_case), - test_case->name, - test.status_comment); - - kunit_update_stats(&suite_stats, test_case->status); - kunit_accumulate_stats(&total_stats, param_stats); - } + kunit_suite_for_each_test_case(suite, test_case) + kunit_run_one_test(suite, test_case, &suite_stats, &total_stats); if (suite->suite_exit) suite->suite_exit(suite); - kunit_print_suite_stats(suite, suite_stats, total_stats); + kunit_print_suite_stats(suite, &suite_stats, &total_stats); suite_end: kunit_print_suite_end(suite); -- 2.39.5

2 weeks, 6 days

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[PATCH] selftests: gpio: correctly check the type of /dev/gpiochipX

by Guixin Liu

/dev/gpiochipX is a character device, not a directory, so we should use "test -c" instead of "test -d" to check for its existence; otherwise, the current check will not work correctly when /dev/gpiochipX is left over (e.g., as a stale device node). Signed-off-by: Guixin Liu <kanie(a)linux.alibaba.com> --- tools/testing/selftests/gpio/gpio-aggregator.sh | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/gpio/gpio-aggregator.sh b/tools/testing/selftests/gpio/gpio-aggregator.sh index 9b6f80ad9f8a..13d8e1607571 100755 --- a/tools/testing/selftests/gpio/gpio-aggregator.sh +++ b/tools/testing/selftests/gpio/gpio-aggregator.sh @@ -351,7 +351,7 @@ test "$(agg_get_chip_num_lines _sysfs.0)" = "1" || fail "number of lines is not test "$(agg_get_line_name _sysfs.0 0)" = "" || fail "line name is unset" echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device" test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains" -test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" +test -c /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" echo "1.2.2. Complex creation/deletion" echo "chip0bank0_0 chip1_bank1 10-11" > "$SYSFS_AGG_DIR/new_device" @@ -365,7 +365,7 @@ test "$(agg_get_line_name _sysfs.0 1)" = "" || fail "line name is unset" test "$(agg_get_line_name _sysfs.0 2)" = "" || fail "line name is unset" echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device" test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains" -test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" +test -c /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" echo "1.2.3. Asynchronous creation with deferred probe" sim_disable_chip chip0 @@ -382,7 +382,7 @@ test "$(agg_get_chip_num_lines _sysfs.0)" = "1" || fail "number of lines is not test "$(agg_get_line_name _sysfs.0 0)" = "" || fail "line name unexpectedly set" echo "$(agg_configfs_dev_name _sysfs.0)" > "$SYSFS_AGG_DIR/delete_device" test -d $CONFIGFS_AGG_DIR/_sysfs.0 && fail "_sysfs.0 unexpectedly remains" -test -d /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" +test -c /dev/${CHIPNAME} && fail "/dev/${CHIPNAME} unexpectedly remains" echo "1.2.4. Can't instantiate a chip with invalid configuration" echo "xyz 0" > "$SYSFS_AGG_DIR/new_device" -- 2.43.0

2 weeks, 6 days

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[GIT PULL] kunit next update for Linux 6.19-rc1

by Shuah Khan

Hi Linus, Please pull the following kunit next update for Linux 6.19-rc1. Makes filter parameters configurable via Kconfig. Adds description of kunit.enable parameter documentation. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 3a8660878839faadb4f1a6dd72c3179c1df56787: Linux 6.18-rc1 (2025-10-12 13:42:36 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-kunit-6.19-rc1 for you to fetch changes up to 7bc16e72ddb993d706f698c2f6cee694e485f557: kunit: Make filter parameters configurable via Kconfig (2025-11-14 11:02:34 -0700) ---------------------------------------------------------------- linux_kselftest-kunit-6.19-rc1 Makes filter parameters configurable via Kconfig. Adds description of kunit.enable parameter documentation. ---------------------------------------------------------------- Thomas Weißschuh (1): kunit: Make filter parameters configurable via Kconfig Yuya Ishikawa (1): Documentation: kunit: add description of kunit.enable parameter Documentation/dev-tools/kunit/run_manual.rst | 6 ++++++ lib/kunit/Kconfig | 24 ++++++++++++++++++++++++ lib/kunit/executor.c | 8 +++++--- 3 files changed, 35 insertions(+), 3 deletions(-) ----------------------------------------------------------------

3 weeks

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[GIT PULL] kselftest next update for Linux 6.19-rc1

by Shuah Khan

Hi Linus, Please pull this kselftest next update for Linux 6.19-rc1 Adds basic test for trace_marker_raw file to tracing selftest. Fixes invalid array access in printf dma_map_benchmark selftest. Adds tprobe enable/disable testcase to tracing selftest. Updates fprobe selftest for ftrace based fprobe. diff is attached. thanks, -- Shuah ---------------------------------------------------------------- The following changes since commit 3a8660878839faadb4f1a6dd72c3179c1df56787: Linux 6.18-rc1 (2025-10-12 13:42:36 -0700) are available in the Git repository at: git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest tags/linux_kselftest-next-6.19-rc1 for you to fetch changes up to a2f7990d330937a204b86b9cafbfef82f87a8693: selftests: tracing: Update fprobe selftest for ftrace based fprobe (2025-11-19 15:55:14 -0700) ---------------------------------------------------------------- linux_kselftest-next-6.19-rc1 Adds basic test for trace_marker_raw file to tracing selftest. Fixes invalid array access in printf dma_map_benchmark selftest. Adds tprobe enable/disable testcase to tracing selftest. Updates fprobe selftest for ftrace based fprobe. ---------------------------------------------------------------- Brendan Jackman (1): selftests/run_kselftest.sh: exit with error if tests fail Masami Hiramatsu (Google) (2): selftests: tracing: Add tprobe enable/disable testcase selftests: tracing: Update fprobe selftest for ftrace based fprobe Steven Rostedt (1): selftests/tracing: Add basic test for trace_marker_raw file Zhang Chujun (1): selftests/dma: fix invalid array access in printf tools/testing/selftests/dma/dma_map_benchmark.c | 2 +- .../ftrace/test.d/00basic/trace_marker_raw.tc | 107 +++++++++++++++++++++ .../ftrace/test.d/dynevent/add_remove_fprobe.tc | 18 +--- .../test.d/dynevent/enable_disable_tprobe.tc | 40 ++++++++ tools/testing/selftests/kselftest/runner.sh | 14 ++- tools/testing/selftests/run_kselftest.sh | 14 +++ 6 files changed, 176 insertions(+), 19 deletions(-) create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/enable_disable_tprobe.tc ----------------------------------------------------------------

3 weeks

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Problems when trying to build tools/testing/selftests

by Guenter Roeck

Hi, when trying to build tools/testing/selftests, I get a lot of warnings such as mount-notify_test.c: In function ‘fanotify_fsmount’: mount-notify_test.c:360:14: warning: implicit declaration of function ‘fsopen’; did you mean ‘fdopen’? and subsequent build errors. testing/selftests/filesystems/mount-notify/mount-notify_test.c:360: undefined reference to `fsopen' /usr/bin/ld: tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c:363: undefined reference to `fsconfig' /usr/bin/ld:tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c:366: undefined reference to `fsmount' /usr/bin/ld: tools/testing/selftests/filesystems/mount-notify/mount-notify_test.c:371: undefined reference to `move_mount' This does not just affect a single file, but several of them. What am I missing ? Is there some magic needed to build the selftests ? Thanks, Guenter

3 weeks

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[PATCH v2 00/13] tools/nolibc: always use 64-bit time-related types

by Thomas Weißschuh

nolibc currently uses 32-bit types for various APIs. These are problematic as their reduced value range can lead to truncated values. Intended for 6.19. Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- Changes in v2: - Drop already applied ino_t and off_t patches. - Also handle 'struct timeval'. - Make the progression of the series a bit clearer. - Add compatibility assertions. - Link to v1: https://lore.kernel.org/r/20251029-nolibc-uapi-types-v1-0-e79de3b215d8@weis… --- Thomas Weißschuh (13): tools/nolibc/poll: use kernel types for system call invocations tools/nolibc/poll: drop __NR_poll fallback tools/nolibc/select: drop non-pselect based implementations tools/nolibc/time: drop invocation of gettimeofday system call tools/nolibc: prefer explicit 64-bit time-related system calls tools/nolibc/gettimeofday: avoid libgcc 64-bit divisions tools/nolibc/select: avoid libgcc 64-bit multiplications tools/nolibc: use custom structs timespec and timeval tools/nolibc: always use 64-bit time types selftests/nolibc: test compatibility of nolibc and kernel time types tools/nolibc: remove time conversions tools/nolibc: add __nolibc_static_assert() selftests/nolibc: add static assertions around time types handling tools/include/nolibc/arch-s390.h | 3 + tools/include/nolibc/compiler.h | 2 + tools/include/nolibc/poll.h | 14 ++-- tools/include/nolibc/std.h | 2 +- tools/include/nolibc/sys/select.h | 25 ++----- tools/include/nolibc/sys/time.h | 6 +- tools/include/nolibc/sys/timerfd.h | 32 +++------ tools/include/nolibc/time.h | 102 +++++++++------------------ tools/include/nolibc/types.h | 17 ++++- tools/testing/selftests/nolibc/nolibc-test.c | 27 +++++++ 10 files changed, 107 insertions(+), 123 deletions(-) --- base-commit: 586e8d5137dfcddfccca44c3b992b92d2be79347 change-id: 20251001-nolibc-uapi-types-1c072d10fcc7 Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

3 weeks

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[PATCH] Documentation: arm: keystone: fix deadlink

by Soham Metha

The binding file 'keystone.txt' has been converted to a DT schema. The current binding is located at: Documentation/devicetree/bindings/arm/ti/ti,keystone.yaml This change was made in https://lore.kernel.org/all/20250806212824.1635084-1-robh@kernel.org/ and merged in commit '20b3c9a403ee23e57a7e6bf5370ca438c3cd2e99' Signed-off-by: Soham Metha <sohammetha01(a)gmail.com> --- Documentation/arch/arm/keystone/overview.rst | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Documentation/arch/arm/keystone/overview.rst b/Documentation/arch/arm/keystone/overview.rst index cd90298c493c..bf791b2fc43f 100644 --- a/Documentation/arch/arm/keystone/overview.rst +++ b/Documentation/arch/arm/keystone/overview.rst @@ -65,7 +65,7 @@ specified through DTS. Following are the DTS used: The device tree documentation for the keystone machines are located at - Documentation/devicetree/bindings/arm/keystone/keystone.txt + Documentation/devicetree/bindings/arm/ti/ti,keystone.yaml Document Author --------------- -- 2.34.1

3 weeks

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[PATCH] selftests/seccomp: fix pointer type mismatch in UPROBE test

by Nirbhay Sharma

Fix compilation error in UPROBE_setup caused by pointer type mismatch in ternary expression. The probed_uretprobe and probed_uprobe function pointers have different type attributes (__attribute__((nocf_check))), which causes the conditional operator to fail with: seccomp_bpf.c:5175:74: error: pointer type mismatch in conditional expression [-Wincompatible-pointer-types] Cast both function pointers to 'const void *' to match the expected parameter type of get_uprobe_offset(), resolving the type mismatch while preserving the function selection logic. Signed-off-by: Nirbhay Sharma <nirbhay.lkd(a)gmail.com> --- tools/testing/selftests/seccomp/seccomp_bpf.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 874f17763536..e13ffe18ef95 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5172,7 +5172,8 @@ FIXTURE_SETUP(UPROBE) ASSERT_GE(bit, 0); } - offset = get_uprobe_offset(variant->uretprobe ? probed_uretprobe : probed_uprobe); + offset = get_uprobe_offset(variant->uretprobe ? + (const void *)probed_uretprobe : (const void *)probed_uprobe); ASSERT_GE(offset, 0); if (variant->uretprobe) -- 2.48.1

3 weeks

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[PATCH bpf-next 0/3] bpf: Fix unintended eviction when updating lru hash maps

by Leon Hwang

This unintended LRU eviction issue was observed while developing the selftest for "[PATCH bpf-next v10 0/8] bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags for percpu maps" [1]. When updating an existing element in lru_hash or lru_percpu_hash maps, the current implementation calls prealloc_lru_pop() to get a new node before checking if the key already exists. If the map is full, this triggers LRU eviction and removes an existing element, even though the update operation only needs to modify the value in-place. In the selftest, this was to be worked around by reserving an extra entry to avoid triggering eviction in __htab_lru_percpu_map_update_elem(). However, the underlying issue remains problematic because: 1. Users may unexpectedly lose entries when updating existing keys in a full map. 2. The eviction overhead is unnecessary for existing key updates. This patchset fixes the issue by first checking if the key exists before allocating a new node. If the key is found, update the value in-place, refresh the LRU reference, and return immediately without triggering any eviction. Only proceed with node allocation if the key does not exist. Links: [1] https://lore.kernel.org/bpf/20251117162033.6296-1-leon.hwang@linux.dev/ Leon Hwang (3): bpf: Avoid unintended eviction when updating lru_hash maps bpf: Avoid unintended eviction when updating lru_percpu_hash maps selftests/bpf: Add tests to verify no unintended eviction when updating lru hash maps kernel/bpf/hashtab.c | 43 +++++++++++ .../selftests/bpf/prog_tests/htab_update.c | 73 +++++++++++++++++++ 2 files changed, 116 insertions(+) -- 2.52.0

3 weeks

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[PATCH v4 0/3] selftests: cgroup: Enhance robustness with polling helpers

by Guopeng Zhang

Hi all, This patch series introduces improvements to the cgroup selftests by adding helper functions to better handle asynchronous updates in cgroup statistics. These changes are especially useful for managing cgroup stats like memory.stat and cgroup.stat, which can be affected by delays (e.g., RCPU callbacks and asynchronous rstat flushing). v4: - Patch 1/3: Adds the `cg_read_key_long_poll()` helper to poll cgroup keys with retries and configurable intervals. - Patch 2/3: Updates `test_memcg_sock()` to use `cg_read_key_long_poll()` for handling delayed "sock" counter updates in memory.stat. - Patch 3/3: Replaces `sleep` and retry logic in `test_kmem_dead_cgroups()` with `cg_read_key_long_poll()` for waiting on `nr_dying_descendants`. v3: - Move `MEMCG_SOCKSTAT_WAIT_*` defines after the `#include` block as suggested. v2: - Clarify the rationale for the 3s timeout and mention the periodic rstat flush interval (FLUSH_TIME = 2*HZ) in the comment. - Replace hardcoded retry count and wait interval with macros to avoid magic numbers and make the timeout calculation explicit. Thanks to Michal Koutný for the suggestion to introduce the polling helper, and to Lance Yang for the review. Guopeng Zhang (3): selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key with retries selftests: cgroup: make test_memcg_sock robust against delayed sock stats selftests: cgroup: Replace sleep with cg_read_key_long_poll() for waiting on nr_dying_descendants .../selftests/cgroup/lib/cgroup_util.c | 21 +++++++++++++ .../cgroup/lib/include/cgroup_util.h | 5 +++ tools/testing/selftests/cgroup/test_kmem.c | 31 ++++++++----------- .../selftests/cgroup/test_memcontrol.c | 20 +++++++++++- 4 files changed, 58 insertions(+), 19 deletions(-) -- 2.25.1

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