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authorPavel Begunkov <asml.silence@gmail.com>2020-11-06 01:31:37 +0300
committerJens Axboe <axboe@kernel.dk>2020-11-06 01:36:40 +0300
commit9a472ef7a3690ac0b77ebfb04c88fa795de2adea (patch)
tree52601c2f161cccd8057364f971a070a03211d023 /fs
parent6b47ab81c9a9b56a94882815e9949d40e4207c92 (diff)
downloadlinux-9a472ef7a3690ac0b77ebfb04c88fa795de2adea.tar.xz
io_uring: fix link lookup racing with link timeout
We can't just go over linked requests because it may race with linked timeouts. Take ctx->completion_lock in that case. Cc: stable@vger.kernel.org # v5.7+ Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
-rw-r--r--fs/io_uring.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 29f1417690d5..8018c7076b25 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8470,7 +8470,21 @@ static bool io_timeout_remove_link(struct io_ring_ctx *ctx,
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
- return io_match_link(container_of(work, struct io_kiocb, work), data);
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ bool ret;
+
+ if (req->flags & REQ_F_LINK_TIMEOUT) {
+ unsigned long flags;
+ struct io_ring_ctx *ctx = req->ctx;
+
+ /* protect against races with linked timeouts */
+ spin_lock_irqsave(&ctx->completion_lock, flags);
+ ret = io_match_link(req, data);
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+ } else {
+ ret = io_match_link(req, data);
+ }
+ return ret;
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)