Linux-kselftest-mirror June 2025

linux-kselftest-mirror@lists.linaro.org

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244 discussions

[PATCH bpf-next 1/2] bpf: Add bpf_task_cwd_from_pid() kfunc

by Rong Tao

From: Rong Tao <rongtao(a)cestc.cn> It is a bit troublesome to get cwd based on pid in bpf program, such as bpftrace example [1]. This patch therefore adds a new bpf_task_cwd_from_pid() kfunc which allows BPF programs to get cwd from a pid. [1] https://github.com/bpftrace/bpftrace/issues/3314 Signed-off-by: Rong Tao <rongtao(a)cestc.cn> --- kernel/bpf/helpers.c | 45 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index b71e428ad936..0f32fbc997bb 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -24,6 +24,10 @@ #include <linux/bpf_mem_alloc.h> #include <linux/kasan.h> #include <linux/bpf_verifier.h> +#include <linux/fs.h> +#include <linux/fs_struct.h> +#include <linux/path.h> +#include <linux/string.h> #include "../../lib/kstrtox.h" @@ -2643,6 +2647,46 @@ __bpf_kfunc struct task_struct *bpf_task_from_vpid(s32 vpid) return p; } +/** + * bpf_task_cwd_from_pid - Get a task's absolute pathname of the current + * working directory from its pid. + * @pid: The pid of the task being looked up. + * @buf: The array pointed to by buf. + * @buf_len: buf length. + */ +__bpf_kfunc int bpf_task_cwd_from_pid(s32 pid, char *buf, u32 buf_len) +{ + struct path pwd; + char kpath[256], *path; + struct task_struct *task; + + if (!buf || buf_len == 0) + return -EINVAL; + + rcu_read_lock(); + task = pid_task(find_vpid(pid), PIDTYPE_PID); + if (!task) { + rcu_read_unlock(); + return -ESRCH; + } + task_lock(task); + if (!task->fs) { + task_unlock(task); + return -ENOENT; + } + get_fs_pwd(task->fs, &pwd); + task_unlock(task); + rcu_read_unlock(); + + path = d_path(&pwd, kpath, sizeof(kpath)); + path_put(&pwd); + if (IS_ERR(path)) + return PTR_ERR(path); + + strncpy(buf, path, buf_len); + return 0; +} + /** * bpf_dynptr_slice() - Obtain a read-only pointer to the dynptr data. * @p: The dynptr whose data slice to retrieve @@ -3314,6 +3358,7 @@ BTF_ID_FLAGS(func, bpf_task_get_cgroup1, KF_ACQUIRE | KF_RCU | KF_RET_NULL) #endif BTF_ID_FLAGS(func, bpf_task_from_pid, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_task_from_vpid, KF_ACQUIRE | KF_RET_NULL) +BTF_ID_FLAGS(func, bpf_task_cwd_from_pid, KF_RET_NULL) BTF_ID_FLAGS(func, bpf_throw) #ifdef CONFIG_BPF_EVENTS BTF_ID_FLAGS(func, bpf_send_signal_task, KF_TRUSTED_ARGS) -- 2.49.0

3 weeks

[PATCH AUTOSEL 6.12 69/93] selftests: harness: Mark functions without prototypes static

by Sasha Levin

From: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> [ Upstream commit c2bcc8e9577a35f9cf4707f8bb0b58bce30991aa ] With -Wmissing-prototypes the compiler will warn about non-static functions which don't have a prototype defined. As they are not used from a different compilation unit they don't need to be defined globally. Avoid the issue by marking the functions static. Signed-off-by: Thomas Weißschuh <thomas.weissschuh(a)linutronix.de> Reviewed-by: Muhammad Usama Anjum <usama.anjum(a)collabora.com> Acked-by: Shuah Khan <skhan(a)linuxfoundation.org> Link: https://lore.kernel.org/r/20250505-nolibc-kselftest-harness-v4-4-ee4dd52571… Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- **YES** This commit should be backported to stable kernel trees. **Rationale:** 1. **Legitimate Build Fix**: The commit addresses a real compiler warning issue (`-Wmissing-prototypes`) that affects build cleanliness and code quality. Modern build systems increasingly use stricter warning flags, making this fix valuable for stable trees. 2. **Zero Functional Risk**: The changes are purely cosmetic from a runtime perspective. Adding `static` to functions that were already internal has no impact on functionality, memory layout, or behavior - it only affects compiler symbol visibility and warnings. 3. **Minimal and Contained**: The diff is extremely small (4 function signatures with `static` added) and isolated to the kselftest harness framework. There are no complex logic changes or cross-subsystem impacts. 4. **Testing Infrastructure Improvement**: While the kselftest framework isn't critical runtime code, it's important for kernel testing and validation. Improving build compliance in testing infrastructure benefits stable kernel maintenance. 5. **Standard Practice**: Compiler warning fixes of this nature (adding missing `static` keywords) are routinely backported to stable trees as they represent good coding practices without functional risk. 6. **Different from Similar Commits**: Unlike the referenced similar commits (all marked "NO") which involved feature additions, API changes, or structural modifications, this commit is purely a build compliance fix with no behavioral changes. The commit meets all stable tree criteria: it fixes an issue (compiler warnings), has minimal risk (no functional changes), and improves code quality without introducing new features or architectural changes. Tools like `kselftest_harness.h:241`, `kselftest_harness.h:290`, `kselftest_harness.h:970`, and `kselftest_harness.h:1188` are the specific locations where these low- risk improvements are made. tools/testing/selftests/kselftest_harness.h | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 666c9fde76da9..7c337b4fa054d 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -258,7 +258,7 @@ * A bare "return;" statement may be used to return early. */ #define FIXTURE_SETUP(fixture_name) \ - void fixture_name##_setup( \ + static void fixture_name##_setup( \ struct __test_metadata __attribute__((unused)) *_metadata, \ FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \ const FIXTURE_VARIANT(fixture_name) \ @@ -307,7 +307,7 @@ __FIXTURE_TEARDOWN(fixture_name) #define __FIXTURE_TEARDOWN(fixture_name) \ - void fixture_name##_teardown( \ + static void fixture_name##_teardown( \ struct __test_metadata __attribute__((unused)) *_metadata, \ FIXTURE_DATA(fixture_name) __attribute__((unused)) *self, \ const FIXTURE_VARIANT(fixture_name) \ @@ -987,7 +987,7 @@ static void __timeout_handler(int sig, siginfo_t *info, void *ucontext) kill(-(t->pid), SIGKILL); } -void __wait_for_test(struct __test_metadata *t) +static void __wait_for_test(struct __test_metadata *t) { struct sigaction action = { .sa_sigaction = __timeout_handler, @@ -1205,9 +1205,9 @@ static bool test_enabled(int argc, char **argv, return !has_positive; } -void __run_test(struct __fixture_metadata *f, - struct __fixture_variant_metadata *variant, - struct __test_metadata *t) +static void __run_test(struct __fixture_metadata *f, + struct __fixture_variant_metadata *variant, + struct __test_metadata *t) { struct __test_xfail *xfail; char test_name[1024]; -- 2.39.5

3 weeks

[PATCH AUTOSEL 6.14 076/102] selftests: harness: Mark functions without prototypes static

by Sasha Levin

3 weeks

[PATCH AUTOSEL 6.15 082/110] selftests: harness: Mark functions without prototypes static

by Sasha Levin

3 weeks

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Linux-kselftest-mirror June 2025