This is a note to let you know that I've just added the patch titled
bpf: Eliminate remaining "make W=1" warnings in kernel/bpf/btf.o
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-eliminate-remaining-make-w-1-warnings-in-kernel-.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4e5c94e4315883f327d91b409d0b7df47194abef
Author: Alan Maguire <alan.maguire@xxxxxxxxxx>
Date: Fri Jul 12 10:28:59 2024 +0100
bpf: Eliminate remaining "make W=1" warnings in kernel/bpf/btf.o
[ Upstream commit 2454075f8e2915cebbe52a1195631bc7efe2b7e1 ]
As reported by Mirsad [1] we still see format warnings in kernel/bpf/btf.o
at W=1 warning level:
CC kernel/bpf/btf.o
./kernel/bpf/btf.c: In function ‘btf_type_seq_show_flags’:
./kernel/bpf/btf.c:7553:21: warning: assignment left-hand side might be a candidate for a format attribute [-Wsuggest-attribute=format]
7553 | sseq.showfn = btf_seq_show;
| ^
./kernel/bpf/btf.c: In function ‘btf_type_snprintf_show’:
./kernel/bpf/btf.c:7604:31: warning: assignment left-hand side might be a candidate for a format attribute [-Wsuggest-attribute=format]
7604 | ssnprintf.show.showfn = btf_snprintf_show;
| ^
Combined with CONFIG_WERROR=y these can halt the build.
The fix (annotating the structure field with __printf())
suggested by Mirsad resolves these. Apologies I missed this last time.
No other W=1 warnings were observed in kernel/bpf after this fix.
[1] https://lore.kernel.org/bpf/92c9d047-f058-400c-9c7d-81d4dc1ef71b@xxxxxxxxx/
Fixes: b3470da314fd ("bpf: annotate BTF show functions with __printf")
Reported-by: Mirsad Todorovac <mtodorovac69@xxxxxxxxx>
Suggested-by: Mirsad Todorovac <mtodorovac69@xxxxxxxxx>
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240712092859.1390960-1-alan.maguire@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 326feb2301700..cfbb038d150c4 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -340,7 +340,7 @@ static const char *btf_type_str(const struct btf_type *t)
struct btf_show {
u64 flags;
void *target; /* target of show operation (seq file, buffer) */
- void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
+ __printf(2, 0) void (*showfn)(struct btf_show *show, const char *fmt, va_list args);
const struct btf *btf;
/* below are used during iteration */
struct {
