bpf: Fix fds_example SIGSEGV error

The `BPF_LOG_BUF_SIZE`'s value is `UINT32_MAX >> 8`, so define an array with it on stack caused an overflow. Signed-off-by: Wenbo Zhang <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
intel-lab-lkp · Jul 10, 2020 · eef8a42 · eef8a42
1 parent 5c3320d
commit eef8a42
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/samples/bpf/fds_example.c b/samples/bpf/fds_example.c
@@ -30,6 +30,8 @@
 #define BPF_M_MAP	1
 #define BPF_M_PROG	2
 
+char bpf_log_buf[BPF_LOG_BUF_SIZE];
+
 static void usage(void)
 {
 	printf("Usage: fds_example [...]\n");
@@ -57,7 +59,6 @@ static int bpf_prog_create(const char *object)
 		BPF_EXIT_INSN(),
 	};
 	size_t insns_cnt = sizeof(insns) / sizeof(struct bpf_insn);
-	char bpf_log_buf[BPF_LOG_BUF_SIZE];
 	struct bpf_object *obj;
 	int prog_fd;