[PATCH] io_uring: don't submit sqes when ctx->refs is dying

[Hao Xu <haoxu@linux.alibaba.com>]

When doing __io_uring_register() and waiting for references to exit,
there could be other threads calling io_uring_enter() and submitting
sqes which may cause the drain wait endless. So avoid this case by
checking if ctx->refs is dying.

Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
---
 fs/io_uring.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 931671082e61..9aab4d25c2df 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9356,6 +9356,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
 		}
 		submitted = to_submit;
 	} else if (to_submit) {
+		if (unlikely(percpu_ref_is_dying(&ctx->refs)))
+			goto out;
 		ret = io_uring_add_task_file(ctx, f.file);
 		if (unlikely(ret))
 			goto out;
-- 
1.8.3.1