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From: Arnd Bergmann <arnd@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Emil Tsalapatis <emil@etsalapatis.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
	Yonghong Song <yonghong.song@linux.dev>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@kernel.org>,
	Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
	Jiri Olsa <jolsa@kernel.org>,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] bpf: fix dump_stack() type cast
Date: Tue,  8 Jul 2025 18:07:29 +0200	[thread overview]
Message-ID: <20250708160737.1834080-1-arnd@kernel.org> (raw)

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


             reply	other threads:[~2025-07-08 16:07 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-08 16:07 Arnd Bergmann [this message]
2025-07-08 19:07 ` [PATCH] bpf: fix dump_stack() type cast Eduard Zingerman

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