From 6cc47d1d2a9b631f62405f56df651975c7587a97 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Wed, 18 Sep 2019 11:18:23 -0600 Subject: [PATCH] io_uring: ensure poll commands clear ->sqe 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 --- fs/io_uring.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 1621243..f9139f5 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -446,16 +446,15 @@ 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); @@ -1714,6 +1713,7 @@ 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; -- 2.7.4