* [PATCH] bpf: fix dump_stack() type cast
@ 2025-07-08 16:07 Arnd Bergmann
2025-07-08 19:07 ` Eduard Zingerman
0 siblings, 1 reply; 2+ messages in thread
From: Arnd Bergmann @ 2025-07-08 16:07 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Kumar Kartikeya Dwivedi, Emil Tsalapatis
Cc: Arnd Bergmann, Martin KaFai Lau, Eduard Zingerman, Song Liu,
Yonghong Song, John Fastabend, KP Singh, Stanislav Fomichev,
Hao Luo, Jiri Olsa, bpf, linux-kernel
From: Arnd Bergmann <arnd@arndb.de>
Passing a pointer as a 'u64' variable requires a double cast when
converting it back to a pointer:
kernel/bpf/stream.c: In function 'dump_stack_cb':
kernel/bpf/stream.c:505:64: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
505 | ctxp->err = bpf_stream_stage_printk(ctxp->ss, "%pS\n", (void *)ip);
| ^
Fixes: d7c431cafcb4 ("bpf: Add dump_stack() analogue to print to BPF stderr")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
kernel/bpf/stream.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/stream.c b/kernel/bpf/stream.c
index 8c842f845245..24433cdf6ede 100644
--- a/kernel/bpf/stream.c
+++ b/kernel/bpf/stream.c
@@ -498,11 +498,11 @@ static bool dump_stack_cb(void *cookie, u64 ip, u64 sp, u64 bp)
if (ret < 0)
goto end;
ctxp->err = bpf_stream_stage_printk(ctxp->ss, "%pS\n %s @ %s:%d\n",
- (void *)ip, line, file, num);
+ (void *)(uintptr_t)ip, line, file, num);
return !ctxp->err;
}
end:
- ctxp->err = bpf_stream_stage_printk(ctxp->ss, "%pS\n", (void *)ip);
+ ctxp->err = bpf_stream_stage_printk(ctxp->ss, "%pS\n", (void *)(uintptr_t)ip);
return !ctxp->err;
}
--
2.39.5
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] bpf: fix dump_stack() type cast
2025-07-08 16:07 [PATCH] bpf: fix dump_stack() type cast Arnd Bergmann
@ 2025-07-08 19:07 ` Eduard Zingerman
0 siblings, 0 replies; 2+ messages in thread
From: Eduard Zingerman @ 2025-07-08 19:07 UTC (permalink / raw)
To: Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
Andrii Nakryiko, Kumar Kartikeya Dwivedi, Emil Tsalapatis
Cc: Arnd Bergmann, Martin KaFai Lau, Song Liu, Yonghong Song,
John Fastabend, KP Singh, Stanislav Fomichev, Hao Luo, Jiri Olsa,
bpf, linux-kernel
On Tue, 2025-07-08 at 18:07 +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> Passing a pointer as a 'u64' variable requires a double cast when
> converting it back to a pointer:
>
> kernel/bpf/stream.c: In function 'dump_stack_cb':
> kernel/bpf/stream.c:505:64: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
> 505 | ctxp->err = bpf_stream_stage_printk(ctxp->ss, "%pS\n", (void *)ip);
> | ^
>
> Fixes: d7c431cafcb4 ("bpf: Add dump_stack() analogue to print to BPF stderr")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
This warning is already fixed in
bfa2bb9abd99be ("bpf: Fix improper int-to-ptr cast in dump_stack_cb"),
which landed in bpf-next yesterday.
[...]
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2025-07-08 16:07 [PATCH] bpf: fix dump_stack() type cast Arnd Bergmann
2025-07-08 19:07 ` Eduard Zingerman
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