From 673a55cc49dafe47defb9ad76a73987fe89e5d70 Mon Sep 17 00:00:00 2001 From: Clint George Date: Mon, 15 Dec 2025 14:17:37 +0530 Subject: [PATCH 1/9] kselftest/coredump: use __builtin_trap() instead of null pointer Use __builtin_trap() to truly crash the program instead of dereferencing null pointer which may be optimized by the compiler preventing the crash from occurring [] Testing: The diff between before and after of running the kselftest test of the module shows no regression on system with x86 architecture [] Error log: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/coredump$ make LLVM=1 W=1 CC stackdump_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. CC coredump_socket_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. CC coredump_socket_protocol_test coredump_test_helpers.c:59:6: warning: indirection of non-volatile null pointer will be deleted, not trap [-Wnull-dereference] 59 | i = *(int *)NULL; | ^~~~~~~~~~~~ coredump_test_helpers.c:59:6: note: consider using __builtin_trap() or qualifying pointer with 'volatile' 1 warning generated. Link: https://lore.kernel.org/r/20251215084737.7504-1-clintbgeorge@gmail.com Signed-off-by: Clint George Signed-off-by: Shuah Khan --- tools/testing/selftests/coredump/coredump_test_helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/coredump/coredump_test_helpers.c b/tools/testing/selftests/coredump/coredump_test_helpers.c index a6f6d5f2ae07..5c8adee63641 100644 --- a/tools/testing/selftests/coredump/coredump_test_helpers.c +++ b/tools/testing/selftests/coredump/coredump_test_helpers.c @@ -56,7 +56,7 @@ void crashing_child(void) pthread_create(&thread, NULL, do_nothing, NULL); /* crash on purpose */ - i = *(int *)NULL; + __builtin_trap(); } int create_detached_tmpfs(void) From 0aaff7b109037c0a45def1bed7b76ffaf253f7d0 Mon Sep 17 00:00:00 2001 From: Clint George Date: Mon, 15 Dec 2025 14:19:00 +0530 Subject: [PATCH 2/9] kselftest/anon_inode: replace null pointers with empty arrays Make use of empty (NULL-terminated) array instead of NULL pointer to avoid compiler errors while maintaining the behavior of the function intact [] Testing: The diff between before and after of running the kselftest test of the module shows no regression on system with x86 architecture [] Error log: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/filesystems$ make LLVM=1 W=1 CC devpts_pts CC file_stressor CC anon_inode_test anon_inode_test.c:45:37: warning: null passed to a callee that requires a non-null argument [-Wnonnull] 45 | ASSERT_LT(execveat(fd_context, "", NULL, NULL, AT_EMPTY_PATH), 0); | ^~~~ /usr/lib/llvm-18/lib/clang/18/include/__stddef_null.h:26:14: note: expanded from macro 'NULL' 26 | #define NULL ((void*)0) | ^~~~~~~~~~ ../Desktop/kernel-dev/linux-v1/tools/testing/selftests/../../../tools/testing/selftests/kselftest_harness.h:535:11: note: expanded from macro 'ASSERT_LT' 535 | __EXPECT(expected, #expected, seen, #seen, <, 1) | ^~~~~~~~ ../Desktop/kernel-dev/linux-v1/tools/testing/selftests/../../../tools/testing/selftests/kselftest_harness.h:758:33: note: expanded from macro '__EXPECT' 758 | __typeof__(_expected) __exp = (_expected); \ | ^~~~~~~~~ 1 warning generated. Link: https://lore.kernel.org/r/20251215084900.7590-1-clintbgeorge@gmail.com Signed-off-by: Clint George Signed-off-by: Shuah Khan --- tools/testing/selftests/filesystems/anon_inode_test.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/anon_inode_test.c b/tools/testing/selftests/filesystems/anon_inode_test.c index 94c6c81c2301..2c4c50500116 100644 --- a/tools/testing/selftests/filesystems/anon_inode_test.c +++ b/tools/testing/selftests/filesystems/anon_inode_test.c @@ -42,7 +42,10 @@ TEST(anon_inode_no_exec) fd_context = sys_fsopen("tmpfs", 0); ASSERT_GE(fd_context, 0); - ASSERT_LT(execveat(fd_context, "", NULL, NULL, AT_EMPTY_PATH), 0); + char *const empty_argv[] = {NULL}; + char *const empty_envp[] = {NULL}; + + ASSERT_LT(execveat(fd_context, "", empty_argv, empty_envp, AT_EMPTY_PATH), 0); ASSERT_EQ(errno, EACCES); EXPECT_EQ(close(fd_context), 0); From 3e6ad272bb8b3199bad952e7b077102af2d8df03 Mon Sep 17 00:00:00 2001 From: Clint George Date: Mon, 15 Dec 2025 14:20:22 +0530 Subject: [PATCH 3/9] kselftest/kublk: include message in _Static_assert for C11 compatibility Add descriptive message in the _Static_assert to comply with the C11 standard requirement to prevent compiler from throwing out error. The compiler throws an error when _Static_assert is used without a message as that is a C23 extension. [] Testing: The diff between before and after of running the kselftest test of the module shows no regression on system with x86 architecture [] Error log: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/ublk$ make LLVM=1 W=1 CC kublk In file included from kublk.c:6: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. In file included from null.c:3: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. In file included from file_backed.c:3: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. In file included from common.c:3: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. In file included from stripe.c:3: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. In file included from fault_inject.c:11: ./kublk.h:220:43: error: '_Static_assert' with no message is a C23 extension [-Werror,-Wc23-extensions] 220 | _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); | ^ | , "" 1 error generated. make: *** [../lib.mk:225: ~/Desktop/kernel-dev/linux-v1/tools/testing/selftests/ublk/kublk] Error 1 Link: https://lore.kernel.org/r/20251215085022.7642-1-clintbgeorge@gmail.com Signed-off-by: Clint George Reviewed-by: Ming Lei Signed-off-by: Shuah Khan --- tools/testing/selftests/ublk/kublk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/ublk/kublk.h b/tools/testing/selftests/ublk/kublk.h index fe42705c6d42..e5eb5f762c1c 100644 --- a/tools/testing/selftests/ublk/kublk.h +++ b/tools/testing/selftests/ublk/kublk.h @@ -217,7 +217,7 @@ static inline __u64 build_user_data(unsigned tag, unsigned op, unsigned tgt_data, unsigned q_id, unsigned is_target_io) { /* we only have 7 bits to encode q_id */ - _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7); + _Static_assert(UBLK_MAX_QUEUES_SHIFT <= 7, "UBLK_MAX_QUEUES_SHIFT must be <= 7"); assert(!(tag >> 16) && !(op >> 8) && !(tgt_data >> 16) && !(q_id >> 7)); return tag | (op << 16) | (tgt_data << 24) | From 671ef08d9455f5754d1fc96f5a14e357d6b80936 Mon Sep 17 00:00:00 2001 From: Xiaochen Shen Date: Wed, 17 Dec 2025 11:04:53 +0800 Subject: [PATCH 4/9] selftests/resctrl: Fix a division by zero error on Hygon Change to adjust effective L3 cache size with SNC enabled change introduced the snc_nodes_per_l3_cache() function to detect the Intel Sub-NUMA Clustering (SNC) feature by comparing #CPUs in node0 with #CPUs sharing LLC with CPU0. The function was designed to return: (1) >1: SNC mode is enabled. (2) 1: SNC mode is not enabled or not supported. However, on certain Hygon CPUs, #CPUs sharing LLC with CPU0 is actually less than #CPUs in node0. This results in snc_nodes_per_l3_cache() returning 0 (calculated as cache_cpus / node_cpus). This leads to a division by zero error in get_cache_size(): *cache_size /= snc_nodes_per_l3_cache(); Causing the resctrl selftest to fail with: "Floating point exception (core dumped)" Fix the issue by ensuring snc_nodes_per_l3_cache() returns 1 when SNC mode is not supported on the platform. Updated commit log to fix commit has issues: Shuah Khan Link: https://lore.kernel.org/r/20251217030456.3834956-2-shenxiaochen@open-hieco.net Fixes: a1cd99e700ec ("selftests/resctrl: Adjust effective L3 cache size with SNC enabled") Signed-off-by: Xiaochen Shen Reviewed-by: Reinette Chatre Reviewed-by: Fenghua Yu Signed-off-by: Shuah Khan --- tools/testing/selftests/resctrl/resctrlfs.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/tools/testing/selftests/resctrl/resctrlfs.c b/tools/testing/selftests/resctrl/resctrlfs.c index 195f04c4d158..b9c1bfb6cc02 100644 --- a/tools/testing/selftests/resctrl/resctrlfs.c +++ b/tools/testing/selftests/resctrl/resctrlfs.c @@ -243,6 +243,16 @@ int snc_nodes_per_l3_cache(void) } snc_mode = cache_cpus / node_cpus; + /* + * On some platforms (e.g. Hygon), + * cache_cpus < node_cpus, the calculated snc_mode is 0. + * + * Set snc_mode = 1 to indicate that SNC mode is not + * supported on the platform. + */ + if (!snc_mode) + snc_mode = 1; + if (snc_mode > 1) ksft_print_msg("SNC-%d mode discovered.\n", snc_mode); } From 4f4f01cc333e97b0e63b61ed1a65c928aa662f99 Mon Sep 17 00:00:00 2001 From: Xiaochen Shen Date: Wed, 17 Dec 2025 11:04:54 +0800 Subject: [PATCH 5/9] selftests/resctrl: Define CPU vendor IDs as bits to match usage The CPU vendor IDs are required to be unique bits because they're used for vendor_specific bitmask in the struct resctrl_test. Consider for example their usage in test_vendor_specific_check(): return get_vendor() & test->vendor_specific However, the definitions of CPU vendor IDs in file resctrl.h is quite subtle as a bitmask value: #define ARCH_INTEL 1 #define ARCH_AMD 2 A clearer and more maintainable approach is to define these CPU vendor IDs using BIT(). This ensures each vendor corresponds to a distinct bit and makes it obvious when adding new vendor IDs. Accordingly, update the return types of detect_vendor() and get_vendor() from 'int' to 'unsigned int' to align with their usage as bitmask values and to prevent potentially risky type conversions. Furthermore, introduce a bool flag 'initialized' to simplify the get_vendor() -> detect_vendor() logic. This ensures the vendor ID is detected only once and resolves the ambiguity of using the same variable 'vendor' both as a value and as a state. Link: https://lore.kernel.org/r/20251217030456.3834956-3-shenxiaochen@open-hieco.net Suggested-by: Reinette Chatre Suggested-by: Fenghua Yu Signed-off-by: Xiaochen Shen Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan --- tools/testing/selftests/resctrl/resctrl.h | 7 ++--- .../testing/selftests/resctrl/resctrl_tests.c | 26 +++++++++++++------ 2 files changed, 22 insertions(+), 11 deletions(-) diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 3c51bdac2dfa..4f9c7d04c98d 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -23,6 +23,7 @@ #include #include #include +#include #include "kselftest.h" #define MB (1024 * 1024) @@ -36,8 +37,8 @@ * Define as bits because they're used for vendor_specific bitmask in * the struct resctrl_test. */ -#define ARCH_INTEL 1 -#define ARCH_AMD 2 +#define ARCH_INTEL BIT(0) +#define ARCH_AMD BIT(1) #define END_OF_TESTS 1 @@ -163,7 +164,7 @@ extern int snc_unreliable; extern char llc_occup_path[1024]; int snc_nodes_per_l3_cache(void); -int get_vendor(void); +unsigned int get_vendor(void); bool check_resctrlfs_support(void); int filter_dmesg(void); int get_domain_id(const char *resource, int cpu_no, int *domain_id); diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 5154ffd821c4..42605e2a3b66 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -23,16 +23,24 @@ static struct resctrl_test *resctrl_tests[] = { &l2_noncont_cat_test, }; -static int detect_vendor(void) +static unsigned int detect_vendor(void) { - FILE *inf = fopen("/proc/cpuinfo", "r"); - int vendor_id = 0; + static unsigned int vendor_id; + static bool initialized; char *s = NULL; + FILE *inf; char *res; - if (!inf) + if (initialized) return vendor_id; + inf = fopen("/proc/cpuinfo", "r"); + if (!inf) { + vendor_id = 0; + initialized = true; + return vendor_id; + } + res = fgrep(inf, "vendor_id"); if (res) @@ -45,15 +53,17 @@ static int detect_vendor(void) fclose(inf); free(res); + + initialized = true; return vendor_id; } -int get_vendor(void) +unsigned int get_vendor(void) { - static int vendor = -1; + unsigned int vendor; + + vendor = detect_vendor(); - if (vendor == -1) - vendor = detect_vendor(); if (vendor == 0) ksft_print_msg("Can not get vendor info...\n"); From 367f931e6476747edbde4e7c7b95fc5d5b724934 Mon Sep 17 00:00:00 2001 From: Xiaochen Shen Date: Wed, 17 Dec 2025 11:04:55 +0800 Subject: [PATCH 6/9] selftests/resctrl: Add CPU vendor detection for Hygon The resctrl selftest currently fails on Hygon CPUs that support Platform QoS features, printing the error: "# Can not get vendor info..." This occurs because vendor detection is missing for Hygon CPUs. Fix this by extending the CPU vendor detection logic to include Hygon's vendor ID. Link: https://lore.kernel.org/r/20251217030456.3834956-4-shenxiaochen@open-hieco.net Signed-off-by: Xiaochen Shen Reviewed-by: Reinette Chatre Signed-off-by: Shuah Khan --- tools/testing/selftests/resctrl/resctrl.h | 1 + tools/testing/selftests/resctrl/resctrl_tests.c | 2 ++ 2 files changed, 3 insertions(+) diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 4f9c7d04c98d..afe635b6e48d 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -39,6 +39,7 @@ */ #define ARCH_INTEL BIT(0) #define ARCH_AMD BIT(1) +#define ARCH_HYGON BIT(2) #define END_OF_TESTS 1 diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 42605e2a3b66..dbcd5eea9fbc 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -50,6 +50,8 @@ static unsigned int detect_vendor(void) vendor_id = ARCH_INTEL; else if (s && !strcmp(s, ": AuthenticAMD\n")) vendor_id = ARCH_AMD; + else if (s && !strcmp(s, ": HygonGenuine\n")) + vendor_id = ARCH_HYGON; fclose(inf); free(res); From 86063a2568b8f2eeb68da1411b320c0ff778f852 Mon Sep 17 00:00:00 2001 From: Xiaochen Shen Date: Wed, 17 Dec 2025 11:04:56 +0800 Subject: [PATCH 7/9] selftests/resctrl: Fix non-contiguous CBM check for Hygon The resctrl selftest currently fails on Hygon CPUs that always supports non-contiguous CBM, printing the error: "# Hardware and kernel differ on non-contiguous CBM support!" This occurs because the arch_supports_noncont_cat() function lacks vendor detection for Hygon CPUs, preventing proper identification of their non-contiguous CBM capability. Fix this by adding Hygon vendor ID detection to arch_supports_noncont_cat(). Link: https://lore.kernel.org/r/20251217030456.3834956-5-shenxiaochen@open-hieco.net Signed-off-by: Xiaochen Shen Reviewed-by: Reinette Chatre Reviewed-by: Fenghua Yu Signed-off-by: Shuah Khan --- tools/testing/selftests/resctrl/cat_test.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c index 94cfdba5308d..f00b622c1460 100644 --- a/tools/testing/selftests/resctrl/cat_test.c +++ b/tools/testing/selftests/resctrl/cat_test.c @@ -290,8 +290,10 @@ static int cat_run_test(const struct resctrl_test *test, const struct user_param static bool arch_supports_noncont_cat(const struct resctrl_test *test) { - /* AMD always supports non-contiguous CBM. */ - if (get_vendor() == ARCH_AMD) + unsigned int vendor_id = get_vendor(); + + /* AMD and Hygon always support non-contiguous CBM. */ + if (vendor_id == ARCH_AMD || vendor_id == ARCH_HYGON) return true; #if defined(__i386__) || defined(__x86_64__) /* arch */ From 3ec6cefc398b93e5f28500f80e7321a80fffee8a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ricardo=20B=2E=20Marli=C3=A8re?= Date: Fri, 16 Jan 2026 11:20:54 -0300 Subject: [PATCH 8/9] selftests/run_kselftest.sh: Add `--skip` argument option MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently the only way of excluding certain tests from a collection is by passing all the other tests explicitly via `--test`. Therefore, if the user wants to skip a single test the resulting command line might be too big, depending on the collection. Add an option `--skip` that takes care of that. Link: https://lore.kernel.org/r/20260116-selftests-add_skip_opt-v1-1-ab54afaae81b@suse.com Signed-off-by: Ricardo B. Marlière Signed-off-by: Shuah Khan --- tools/testing/selftests/run_kselftest.sh | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/tools/testing/selftests/run_kselftest.sh b/tools/testing/selftests/run_kselftest.sh index d4be97498b32..84d45254675c 100755 --- a/tools/testing/selftests/run_kselftest.sh +++ b/tools/testing/selftests/run_kselftest.sh @@ -30,6 +30,7 @@ Usage: $0 [OPTIONS] -s | --summary Print summary with detailed log in output.log (conflict with -p) -p | --per-test-log Print test log in /tmp with each test name (conflict with -s) -t | --test COLLECTION:TEST Run TEST from COLLECTION + -S | --skip COLLECTION:TEST Skip TEST from COLLECTION -c | --collection COLLECTION Run all tests from COLLECTION -l | --list List the available collection:test entries -d | --dry-run Don't actually run any tests @@ -43,6 +44,7 @@ EOF COLLECTIONS="" TESTS="" +SKIP="" dryrun="" kselftest_override_timeout="" ERROR_ON_FAIL=true @@ -58,6 +60,9 @@ while true; do -t | --test) TESTS="$TESTS $2" shift 2 ;; + -S | --skip) + SKIP="$SKIP $2" + shift 2 ;; -c | --collection) COLLECTIONS="$COLLECTIONS $2" shift 2 ;; @@ -109,6 +114,12 @@ if [ -n "$TESTS" ]; then done available="$(echo "$valid" | sed -e 's/ /\n/g')" fi +# Remove tests to be skipped from available list +if [ -n "$SKIP" ]; then + for skipped in $SKIP ; do + available="$(echo "$available" | grep -v "^${skipped}$")" + done +fi kselftest_failures_file="$(mktemp --tmpdir kselftest-failures-XXXXXX)" export kselftest_failures_file From 6d6ad32e22f028c525d5df471c5522616e645a6b Mon Sep 17 00:00:00 2001 From: Ziyu Chen Date: Wed, 21 Jan 2026 17:41:47 +0800 Subject: [PATCH 9/9] selftests/pidfd: fix typo in comment MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Fix the typo "untill" → "until" in a comment in pidfd_info_test.c. This typo is already listed in scripts/spelling.txt by commit 66b47b4a9dad ("checkpatch: look for common misspellings"). Link: https://lore.kernel.org/r/20260121094147.4187337-1-chenziyu@uniontech.com Suggested-by: Cryolitia PukNgae Signed-off-by: Ziyu Chen Signed-off-by: Shuah Khan --- tools/testing/selftests/pidfd/pidfd_info_test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c index 6571e04acd88..8bed951e06a0 100644 --- a/tools/testing/selftests/pidfd/pidfd_info_test.c +++ b/tools/testing/selftests/pidfd/pidfd_info_test.c @@ -229,7 +229,7 @@ static void *pidfd_info_pause_thread(void *arg) close(ipc_socket); - /* Sleep untill we're killed. */ + /* Sleep until we're killed. */ pause(); return NULL; }