diff mbox series

[bpf-next,5/5] bpf: fix potential error return

Message ID 20241115004607.3144806-6-aspsk@isovalent.com (mailing list archive)
State New
Delegated to: BPF
Headers show
Series Add fd_array_cnt attribute for BPF_PROG_LOAD | expand

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Commit Message

Anton Protopopov Nov. 15, 2024, 12:46 a.m. UTC
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>
---
 kernel/bpf/core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 14d9288441f2..a15059918768 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 +548,12 @@  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);
+	if (err)
+		return err;
+
+	return 0;
 }
 
 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)