From 7d3460632da2c2ad5c5708db82a0b72e2b66396c Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Mon, 18 Sep 2023 17:52:32 +0200 Subject: [PATCH] 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: ec5290a178b7 ("bpf: Prevent KASAN false positive with bpf_throw") Reported-by: Matthieu Baerts Signed-off-by: Kumar Kartikeya Dwivedi Tested-by: Matthieu Baerts Link: https://lore.kernel.org/r/20230918155233.297024-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- kernel/bpf/helpers.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 7ff2a42f1996..dd1c69ee3375 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -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"); }