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bpf: Mark bpf_btf_find_by_name_kind() as sleepable

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When bpf_btf_find_by_name_kind() finds a type in module BTF, it
returns a new BTF object fd through __btf_new_fd(). This reaches
anon_inode_getfd(), which can sleep while allocating or expanding the
current task fd table.

The helper prototype does not set might_sleep, so the verifier allows
the helper in non-sleepable contexts such as BPF timer callbacks. The
fd allocation can then sleep in softirq context and install the fd into
the interrupted task.

Mark the helper as sleepable. This preserves calls from the main body
of a sleepable syscall program while rejecting calls from its
non-sleepable regions.

Fixes: 3d78417b60 ("bpf: Add bpf_btf_find_by_name_kind() helper.")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/bpf/20260903155150.D57251F000E9@smtp.kernel.org
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260903214758.2727663-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2026-09-03 23:47:49 +02:00 committed by Alexei Starovoitov
parent 22ab49afe1
commit 620614bf76
1 changed files with 1 additions and 0 deletions
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kernel/bpf/btf.c
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@ -8749,6 +8749,7 @@ BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int
const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = {
.func = bpf_btf_find_by_name_kind,
.gpl_only = false,
.might_sleep = true,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
.arg2_type = ARG_MEM_SIZE,