Re: [syzbot] [perf?] WARNING in perf_event_open

[Edward Adam Davis]

please test WARNING in perf_event_open

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 39676dfe5233

diff --git a/mm/madvise.c b/mm/madvise.c
index 912155a94ed5..8fd3e00af243 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1405,6 +1405,9 @@ int do_madvise(struct mm_struct *mm, unsigned long start, size_t len_in, int beh
 	if (!madvise_behavior_valid(behavior))
 		return -EINVAL;
 
+	if (!start)
+		return -EINVAL;
+
 	if (!PAGE_ALIGNED(start))
 		return -EINVAL;
 	len = PAGE_ALIGN(len_in);