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| author | Song Liu <songliubraving@fb.com> | 2021-02-25 15:43:14 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-02-26 11:51:47 -0800 |
| commit | a10787e6d58c24b51e91c19c6d16c5da89fcaa4b (patch) | |
| tree | 115e4d7d43d1353084fc3b9e54935aad16c6f821 /kernel/bpf/bpf_lsm.c | |
| parent | 9c8f21e6f8856a96634e542a58ef3abf27486801 (diff) | |
| download | linux-a10787e6d58c24b51e91c19c6d16c5da89fcaa4b.tar.gz linux-a10787e6d58c24b51e91c19c6d16c5da89fcaa4b.tar.xz | |
bpf: Enable task local storage for tracing programs
To access per-task data, BPF programs usually creates a hash table with
pid as the key. This is not ideal because:
1. The user need to estimate the proper size of the hash table, which may
be inaccurate;
2. Big hash tables are slow;
3. To clean up the data properly during task terminations, the user need
to write extra logic.
Task local storage overcomes these issues and offers a better option for
these per-task data. Task local storage is only available to BPF_LSM. Now
enable it for tracing programs.
Unlike LSM programs, tracing programs can be called in IRQ contexts.
Helpers that access task local storage are updated to use
raw_spin_lock_irqsave() instead of raw_spin_lock_bh().
Tracing programs can attach to functions on the task free path, e.g.
exit_creds(). To avoid allocating task local storage after
bpf_task_storage_free(). bpf_task_storage_get() is updated to not allocate
new storage when the task is not refcounted (task->usage == 0).
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210225234319.336131-2-songliubraving@fb.com
Diffstat (limited to 'kernel/bpf/bpf_lsm.c')
| -rw-r--r-- | kernel/bpf/bpf_lsm.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 1622a44d1617..9829f381b51c 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -115,10 +115,6 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) return &bpf_spin_lock_proto; case BPF_FUNC_spin_unlock: return &bpf_spin_unlock_proto; - case BPF_FUNC_task_storage_get: - return &bpf_task_storage_get_proto; - case BPF_FUNC_task_storage_delete: - return &bpf_task_storage_delete_proto; case BPF_FUNC_bprm_opts_set: return &bpf_bprm_opts_set_proto; case BPF_FUNC_ima_inode_hash: |