Commit 7d346063 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
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bpf: Fix bpf_throw warning on 32-bit arch 



On 32-bit architectures, the pointer width is 32-bit, while we try to
cast from a u64 down to it, the compiler complains on mismatch in
integer size. Fix this by first casting to long which should match
the pointer width on targets supported by Linux.

Fixes: ec5290a1 ("bpf: Prevent KASAN false positive with bpf_throw")
Reported-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Tested-by: default avatarMatthieu Baerts <matthieu.baerts@tessares.net>
Link: https://lore.kernel.org/r/20230918155233.297024-3-memxor@gmail.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 4d84dcc7

kernel/bpf/helpers.c

+1 −1
Original line number Diff line number Diff line
@@ -2488,7 +2488,7 @@ __bpf_kfunc void bpf_throw(u64 cookie) 
	 * deeper stack depths than ctx.sp as we do not return from bpf_throw,

	 * which skips compiler generated instrumentation to do the same.

	 */

	kasan_unpoison_task_stack_below((void *)ctx.sp);

	kasan_unpoison_task_stack_below((void *)(long)ctx.sp);

	ctx.aux->bpf_exception_cb(cookie, ctx.sp, ctx.bp);

	WARN(1, "A call to BPF exception callback should never return\n");

}