From: Pavel Begunkov asml.silence@gmail.com
[ 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@gmail.com Fixes: 05f3fb3c53975 ("io_uring: avoid ring quiesce for fixed file set unregister and update") Signed-off-by: Pavel Begunkov asml.silence@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/io_uring.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 3582db014aad..0a9f9000fc80 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8508,11 +8508,19 @@ 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;