* [PATCH] io_uring: ensure poll commands clear ->sqe
@ 2019-09-18 17:18 Jens Axboe
0 siblings, 0 replies; only message in thread
From: Jens Axboe @ 2019-09-18 17:18 UTC (permalink / raw)
To: linux-block
If we end up getting woken in poll (due to a signal), then we may need
to punt the poll request to an async worker. When we do that, we look up
the list to queue at, deferefencing req->submit.sqe, however that is
only set for requests we initially decided to queue async.
This fixes a crash with poll command usage and wakeups that need to punt
to async context.
Fixes: 54a91f3bb9b9 ("io_uring: limit parallelism of buffered writes")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b550f685eadd..8c28bd7792b6 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -453,16 +453,15 @@ static void __io_commit_cqring(struct io_ring_ctx *ctx)
static inline void io_queue_async_work(struct io_ring_ctx *ctx,
struct io_kiocb *req)
{
- int rw;
+ int rw = 0;
- switch (req->submit.sqe->opcode) {
- case IORING_OP_WRITEV:
- case IORING_OP_WRITE_FIXED:
- rw = !(req->rw.ki_flags & IOCB_DIRECT);
- break;
- default:
- rw = 0;
- break;
+ if (req->submit.sqe) {
+ switch (req->submit.sqe->opcode) {
+ case IORING_OP_WRITEV:
+ case IORING_OP_WRITE_FIXED:
+ rw = !(req->rw.ki_flags & IOCB_DIRECT);
+ break;
+ }
}
queue_work(ctx->sqo_wq[rw], &req->work);
@@ -1721,6 +1720,7 @@ static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
if (!poll->file)
return -EBADF;
+ req->submit.sqe = NULL;
INIT_WORK(&req->work, io_poll_complete_work);
events = READ_ONCE(sqe->poll_events);
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
--
Jens Axboe
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