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authorJens Axboe <axboe@kernel.dk>2021-07-23 20:53:54 +0300
committerJens Axboe <axboe@kernel.dk>2021-07-24 01:44:51 +0300
commit991468dcf198bb87f24da330676724a704912b47 (patch)
treefae574f2aeff461ddfa0e95389f4246960643555
parent3c30ef0f78cfb36fdb13753794b0384cf7e37cc9 (diff)
downloadlinux-991468dcf198bb87f24da330676724a704912b47.tar.xz
io_uring: explicitly catch any illegal async queue attempt
Catch an illegal case to queue async from an unrelated task that got the ring fd passed to it. This should not be possible to hit, but better be proactive and catch it explicitly. io-wq is extended to check for early IO_WQ_WORK_CANCEL being set on a work item as well, so it can run the request through the normal cancelation path. Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--fs/io-wq.c7
-rw-r--r--fs/io_uring.c11
2 files changed, 17 insertions, 1 deletions
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 843d4a7bcd6e..cf086b01c6c6 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -731,7 +731,12 @@ static void io_wqe_enqueue(struct io_wqe *wqe, struct io_wq_work *work)
int work_flags;
unsigned long flags;
- if (test_bit(IO_WQ_BIT_EXIT, &wqe->wq->state)) {
+ /*
+ * If io-wq is exiting for this task, or if the request has explicitly
+ * been marked as one that should not get executed, cancel it here.
+ */
+ if (test_bit(IO_WQ_BIT_EXIT, &wqe->wq->state) ||
+ (work->flags & IO_WQ_WORK_CANCEL)) {
io_run_cancel(work, wqe);
return;
}
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 117dc32eb8a8..5a0fd6bcd318 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1294,6 +1294,17 @@ static void io_queue_async_work(struct io_kiocb *req)
/* init ->work of the whole link before punting */
io_prep_async_link(req);
+
+ /*
+ * Not expected to happen, but if we do have a bug where this _can_
+ * happen, catch it here and ensure the request is marked as
+ * canceled. That will make io-wq go through the usual work cancel
+ * procedure rather than attempt to run this request (or create a new
+ * worker for it).
+ */
+ if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
+ req->work.flags |= IO_WQ_WORK_CANCEL;
+
trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
&req->work, req->flags);
io_wq_enqueue(tctx->io_wq, &req->work);