diff options
| author | Jiri Olsa <jolsa@kernel.org> | 2026-08-03 23:01:42 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2026-08-05 11:32:29 -0700 |
| commit | 15f1bd8574662f1b7b26aaa2e23ebf4066f0117d (patch) | |
| tree | d862a627a30cda3b47afad8adf2d99e4b6e8bcb4 | |
| parent | 09b3fd6caa0b57f8a39254ee5db3af30bdd53c18 (diff) | |
bpf: Disable preemption in bpf_get_stackid
The get_perf_callchain call needs disabled preemption plus we need
it disabled as long as we access its returned trace entries buffer.
Note the bpf_get_stackid_pe function is executed already with
preemption disabled.
Fixes: d5a3b1f69186 ("bpf: introduce BPF_MAP_TYPE_STACK_TRACE")
Reported-by: Tao Chen <chen.dylane@linux.dev>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20260803210149.296496-6-jolsa@kernel.org
Closes: https://lore.kernel.org/bpf/20260206090653.1336687-2-chen.dylane@linux.dev/
| -rw-r--r-- | kernel/bpf/stackmap.c | 24 |
1 files changed, 13 insertions, 11 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 3ee0034daf52..5b18d728f4b8 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -632,20 +632,22 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, return -EINVAL; max_depth = stack_map_calculate_max_depth(map->value_size, elem_size, flags); - trace = get_perf_callchain(regs, kernel, user, max_depth, - false, false, 0); - if (unlikely(!trace)) - /* couldn't fetch the stack trace */ - return -EFAULT; + scoped_guard(preempt) { + trace = get_perf_callchain(regs, kernel, user, max_depth, + false, false, 0); + if (unlikely(!trace)) + /* couldn't fetch the stack trace */ + return -EFAULT; - err = stackid_fastpath(&stackid, map, trace, flags); - if (err != -ENOENT) - return err; + err = stackid_fastpath(&stackid, map, trace, flags); + if (err != -ENOENT) + return err; - new_bucket = stackid_new_bucket(&stackid, map); - if (!new_bucket) - return -ENOMEM; + new_bucket = stackid_new_bucket(&stackid, map); + if (!new_bucket) + return -ENOMEM; + } return stackid_install(&stackid, map, new_bucket, flags); } |