io_uring: correct link-list traversal locking
As io_remove_next_linked() is now under ->timeout_lock (see
io_link_timeout_fn), we should update locking around io_for_each_link()
and io_match_task() to use the new lock.
Cc: stable@kernel.org # 5.15+
Fixes: 89850fce16a1a ("io_uring: run timeouts from task_work")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/b54541cedf7de59cb5ae36109e58529ca16e66aa.1637631883.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e98e7ce..a4c508a 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1502,10 +1502,10 @@ static void io_prep_async_link(struct io_kiocb *req)
if (req->flags & REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
- spin_lock(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
io_for_each_link(cur, req)
io_prep_async_work(cur);
- spin_unlock(&ctx->completion_lock);
+ spin_unlock_irq(&ctx->timeout_lock);
} else {
io_for_each_link(cur, req)
io_prep_async_work(cur);
@@ -5699,6 +5699,7 @@ static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
int posted = 0, i;
spin_lock(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list;
@@ -5708,6 +5709,7 @@ static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
posted += io_poll_remove_one(req);
}
}
+ spin_unlock_irq(&ctx->timeout_lock);
spin_unlock(&ctx->completion_lock);
if (posted)
@@ -9568,9 +9570,9 @@ static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
struct io_ring_ctx *ctx = req->ctx;
/* protect against races with linked timeouts */
- spin_lock(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
ret = io_match_task(req, cancel->task, cancel->all);
- spin_unlock(&ctx->completion_lock);
+ spin_unlock_irq(&ctx->timeout_lock);
} else {
ret = io_match_task(req, cancel->task, cancel->all);
}
@@ -9585,12 +9587,14 @@ static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
LIST_HEAD(list);
spin_lock(&ctx->completion_lock);
+ spin_lock_irq(&ctx->timeout_lock);
list_for_each_entry_reverse(de, &ctx->defer_list, list) {
if (io_match_task(de->req, task, cancel_all)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
}
+ spin_unlock_irq(&ctx->timeout_lock);
spin_unlock(&ctx->completion_lock);
if (list_empty(&list))
return false;