kernel.git/tools/testing/selftests/bpf/bpf_experimental.h, branch master

selftests/bpf: Make bpf get_preempt_count() work for v6.14+ kernels

2026-01-30T20:20:25Z

Recent x86 kernels export __preempt_count as a ksym, while some old kernels between v6.1 and v6.14 expose the preemption counter via pcpu_hot.preempt_count. The existing selftest helper unconditionally dereferenced __preempt_count, which breaks BPF program loading on such old kernels. Make the x86 preemption count lookup version-agnostic by: - Marking __preempt_count and pcpu_hot as weak ksyms. - Introducing a BTF-described pcpu_hot___local layout with preserve_access_index. - Selecting the appropriate access path at runtime using ksym availability and bpf_ksym_exists() and bpf_core_field_exists(). This allows a single BPF binary to run correctly across kernel versions (e.g., v6.18 vs. v6.13) without relying on compile-time version checks. Signed-off-by: Changwoo Min Link: https://lore.kernel.org/r/20260130021843.154885-1-changwoo@igalia.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Introduce execution context detection helpers

2026-01-25T16:20:50Z

Introduce bpf_in_nmi(), bpf_in_hardirq(), bpf_in_serving_softirq(), and bpf_in_task() inline helpers in bpf_experimental.h. These allow BPF programs to query the current execution context with higher granularity than the existing bpf_in_interrupt() helper. While BPF programs can often infer their context from attachment points, subsystems like sched_ext may call the same BPF logic from multiple contexts (e.g., task-to-task wake-ups vs. interrupt-to-task wake-ups). These helpers provide a reliable way for logic to branch based on the current CPU execution state. Implementing these as BPF-native inline helpers wrapping get_preempt_count() allows the compiler and JIT to inline the logic. The implementation accounts for differences in preempt_count layout between standard and PREEMPT_RT kernels. Reviewed-by: Alexei Starovoitov Signed-off-by: Changwoo Min Link: https://lore.kernel.org/r/20260125115413.117502-2-changwoo@igalia.com Signed-off-by: Alexei Starovoitov

bpf: Migrate bpf_wq_set_callback_impl() to KF_IMPLICIT_ARGS

2026-01-21T00:15:57Z

Implement bpf_wq_set_callback() with an implicit bpf_prog_aux argument, and remove bpf_wq_set_callback_impl(). Update special kfunc checks in the verifier accordingly. Reviewed-by: Eduard Zingerman Signed-off-by: Ihor Solodrai Link: https://lore.kernel.org/r/20260120222638.3976562-8-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov

Merge tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2025-10-03T23:32:36Z

Pull file->f_path constification from Al Viro: "Only one thing was modifying ->f_path of an opened file - acct(2). Massaging that away and constifying a bunch of struct path * arguments in functions that might be given &file->f_path ends up with the situation where we can turn ->f_path into an anon union of const struct path f_path and struct path __f_path, the latter modified only in a few places in fs/{file_table,open,namei}.c, all for struct file instances that are yet to be opened" * tag 'pull-f_path' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (23 commits) Have cc(1) catch attempts to modify ->f_path kernel/acct.c: saner struct file treatment configfs:get_target() - release path as soon as we grab configfs_item reference apparmor/af_unix: constify struct path * arguments ovl_is_real_file: constify realpath argument ovl_sync_file(): constify path argument ovl_lower_dir(): constify path argument ovl_get_verity_digest(): constify path argument ovl_validate_verity(): constify {meta,data}path arguments ovl_ensure_verity_loaded(): constify datapath argument ksmbd_vfs_set_init_posix_acl(): constify path argument ksmbd_vfs_inherit_posix_acl(): constify path argument ksmbd_vfs_kern_path_unlock(): constify path argument ksmbd_vfs_path_lookup_locked(): root_share_path can be const struct path * check_export(): constify path argument export_operations->open(): constify path argument rqst_exp_get_by_name(): constify path argument nfs: constify path argument of __vfs_getattr() bpf...d_path(): constify path argument done_path_create(): constify path argument ...

bpf...d_path(): constify path argument

2025-09-16T01:17:08Z

Reviewed-by: Jan Kara Reviewed-by: Christian Brauner Signed-off-by: Al Viro

selftests/bpf: Introduce experimental bpf_in_interrupt()

2025-09-04T16:05:58Z

Filtering pid_tgid is meanlingless when the current task is preempted by an interrupt. To address this, introduce 'bpf_in_interrupt()' helper function, which allows BPF programs to determine whether they are executing in interrupt context. 'get_preempt_count()': * On x86, '*(int *) bpf_this_cpu_ptr(&__preempt_count)'. * On arm64, 'bpf_get_current_task_btf()->thread_info.preempt.count'. Then 'bpf_in_interrupt()' will be: * If !PREEMPT_RT, 'get_preempt_count() & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_MASK)'. * If PREEMPT_RT, '(get_preempt_count() & (NMI_MASK | HARDIRQ_MASK)) | (bpf_get_current_task_btf()->softirq_disable_cnt & SOFTIRQ_MASK)'. As for other archs, it can be added support by updating 'get_preempt_count()'. Suggested-by: Alexei Starovoitov Signed-off-by: Leon Hwang Link: https://lore.kernel.org/r/20250903140438.59517-2-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov

selftests/bpf: Add tests for bpf_cgroup_read_xattr

2025-07-02T12:18:20Z

Add tests for different scenarios with bpf_cgroup_read_xattr: 1. Read cgroup xattr from bpf_cgroup_from_id; 2. Read cgroup xattr from bpf_cgroup_ancestor; 3. Read cgroup xattr from css_iter; 4. Use bpf_cgroup_read_xattr in LSM hook security_socket_connect. 5. Use bpf_cgroup_read_xattr in cgroup program. Signed-off-by: Song Liu Link: https://lore.kernel.org/20250623063854.1896364-5-song@kernel.org Signed-off-by: Christian Brauner

selftests/bpf: Add test for open coded dmabuf_iter

2025-05-27T16:51:26Z

Use the same test buffers as the traditional iterator and a new BPF map to verify the test buffers can be found with the open coded dmabuf iterator. Signed-off-by: T.J. Mercier Acked-by: Christian König Acked-by: Song Liu Link: https://lore.kernel.org/r/20250522230429.941193-6-tjmercier@google.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Introduce cond_break_label

2025-03-15T18:48:56Z

Add a new cond_break_label macro that jumps to the specified label when the cond_break termination check fires, and allows us to better handle the uncontrolled termination of the loop. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20250306035431.2186189-2-memxor@gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add a test for open coded kmem_cache iter

2024-11-01T18:08:32Z

The new subtest runs with bpf_prog_test_run_opts() as a syscall prog. It iterates the kmem_cache using bpf_for_each loop and count the number of entries. Finally it checks it with the number of entries from the regular iterator. $ ./vmtest.sh -- ./test_progs -t kmem_cache_iter ... #130/1 kmem_cache_iter/check_task_struct:OK #130/2 kmem_cache_iter/check_slabinfo:OK #130/3 kmem_cache_iter/open_coded_iter:OK #130 kmem_cache_iter:OK Summary: 1/3 PASSED, 0 SKIPPED, 0 FAILED Also simplify the code by using attach routine of the skeleton. Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20241030222819.1800667-2-namhyung@kernel.org Signed-off-by: Alexei Starovoitov