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| author | Anton Protopopov <aspsk@isovalent.com> | 2024-12-10 11:42:45 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-12-10 11:17:53 -0800 |
| commit | c4441ca86afe4814039ee1b32c39d833c1a16bbc (patch) | |
| tree | 3112465a5fa03bfe57455d23b72a67771819dc28 /kernel/bpf | |
| parent | cf8b876363da4fccdcc4ba209d4d098ec0f1ffac (diff) | |
| download | lwn-c4441ca86afe4814039ee1b32c39d833c1a16bbc.tar.gz lwn-c4441ca86afe4814039ee1b32c39d833c1a16bbc.zip | |
bpf: fix potential error return
The bpf_remove_insns() function returns WARN_ON_ONCE(error), where
error is a result of bpf_adj_branches(), and thus should be always 0
However, if for any reason it is not 0, then it will be converted to
boolean by WARN_ON_ONCE and returned to user space as 1, not an actual
error value. Fix this by returning the original err after the WARN check.
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241210114245.836164-1-aspsk@isovalent.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/core.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6fa8041d4831..da729cbbaeb9 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -539,6 +539,8 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) { + int err; + /* Branch offsets can't overflow when program is shrinking, no need * to call bpf_adj_branches(..., true) here */ @@ -546,7 +548,9 @@ int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) sizeof(struct bpf_insn) * (prog->len - off - cnt)); prog->len -= cnt; - return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); + err = bpf_adj_branches(prog, off, off + cnt, off, false); + WARN_ON_ONCE(err); + return err; } static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) |