Re: INFO: trying to register non-static key in io_cqring_ev_posted

[Jens Axboe <axboe@kernel.dk>]

On 11/20/19 8:58 AM, syzbot wrote:
> syzbot has found a reproducer for the following crash on:
> 
> HEAD commit:    5d1131b4 Add linux-next specific files for 20191119
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=140b0412e00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=b60c562d89e5a8df
> dashboard link: https://syzkaller.appspot.com/bug?extid=0d818c0d39399188f393
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=169b29d2e00000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14b3956ae00000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+0d818c0d39399188f393@syzkaller.appspotmail.com

Thanks, the below should fix it.


diff --git a/fs/io_uring.c b/fs/io_uring.c
index 100931b40301..066b59ffb54e 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4568,12 +4568,18 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
 	ctx->cq_entries = rings->cq_ring_entries;
 
 	size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
-	if (size == SIZE_MAX)
+	if (size == SIZE_MAX) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
 		return -EOVERFLOW;
+	}
 
 	ctx->sq_sqes = io_mem_alloc(size);
-	if (!ctx->sq_sqes)
+	if (!ctx->sq_sqes) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
 		return -ENOMEM;
+	}
 
 	return 0;
 }

-- 
Jens Axboe