diff options
| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2025-07-03 13:48:10 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2025-07-03 19:30:06 -0700 |
| commit | d090326860096df9dac6f27cff76d3f8df44d4f1 (patch) | |
| tree | 2f3958edbb8eb87e8eb46971e81306a923cd487a /kernel/bpf/helpers.c | |
| parent | 0e521efaf36350b8f783984541efa56f560c90b0 (diff) | |
bpf: Ensure RCU lock is held around bpf_prog_ksym_find
Add a warning to ensure RCU lock is held around tree lookup, and then
fix one of the invocations in bpf_stack_walker. The program has an
active stack frame and won't disappear. Use the opportunity to remove
unneeded invocation of is_bpf_text_address.
Fixes: f18b03fabaa9 ("bpf: Implement BPF exceptions")
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250703204818.925464-5-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf/helpers.c')
| -rw-r--r-- | kernel/bpf/helpers.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 6bfcbcdf6588..3d33181d5e67 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -2981,9 +2981,16 @@ static bool bpf_stack_walker(void *cookie, u64 ip, u64 sp, u64 bp) struct bpf_throw_ctx *ctx = cookie; struct bpf_prog *prog; - if (!is_bpf_text_address(ip)) - return !ctx->cnt; + /* + * The RCU read lock is held to safely traverse the latch tree, but we + * don't need its protection when accessing the prog, since it has an + * active stack frame on the current stack trace, and won't disappear. + */ + rcu_read_lock(); prog = bpf_prog_ksym_find(ip); + rcu_read_unlock(); + if (!prog) + return !ctx->cnt; ctx->cnt++; if (bpf_is_subprog(prog)) return true; |