From: Pavel Begunkov <asml.silence@xxxxxxxxx>
[ Upstream commit b0380bf6dad4601d92025841e2b7a135d566c6e3 ]
Fixed file table quiesce might unlock ->uring_lock, potentially letting
new requests to be submitted, don't allow those requests to use the
table as they will race with unregistration.
Reported-and-tested-by: van fantasy <g1042620637@xxxxxxxxx>
Fixes: 05f3fb3c53975 ("io_uring: avoid ring quiesce for fixed file set unregister and update")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/io_uring.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b8e6398d9430..5f111a660fff 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7933,11 +7933,19 @@ static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
+ unsigned nr = ctx->nr_user_files;
int ret;
if (!ctx->file_data)
return -ENXIO;
+
+ /*
+ * Quiesce may unlock ->uring_lock, and while it's not held
+ * prevent new requests using the table.
+ */
+ ctx->nr_user_files = 0;
ret = io_rsrc_ref_quiesce(ctx->file_data, ctx);
+ ctx->nr_user_files = nr;
if (!ret)
__io_sqe_files_unregister(ctx);
return ret;
--
2.35.1
