From 7fbeb95d0f68e21e6ca61284f1ac681630976947 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sun, 16 Feb 2020 01:01:18 +0300 Subject: io_uring: add missing io_req_cancelled() fallocate_finish() is missing cancellation check. Add it. It's safe to do that, as only flags setup and sqe fields copy are done before it gets into __io_fallocate(). Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/io_uring.c b/fs/io_uring.c index 5a826017ebb8..29565d82291f 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2517,6 +2517,9 @@ static void io_fallocate_finish(struct io_wq_work **workptr) struct io_kiocb *nxt = NULL; int ret; + if (io_req_cancelled(req)) + return; + ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); if (ret < 0) @@ -2904,6 +2907,7 @@ static void io_close_finish(struct io_wq_work **workptr) struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct io_kiocb *nxt = NULL; + /* not cancellable, don't do io_req_cancelled() */ __io_close_finish(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); -- cgit v1.2.3-54-g00ecf From 297a31e3e8318f533cff4fe33ffaefb74f72c6e2 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Mon, 17 Feb 2020 17:39:45 +0300 Subject: io_uring: remove unnecessary NULL checks The "kmsg" pointer can't be NULL and we have already dereferenced it so a check here would be useless. Reviewed-by: Stefano Garzarella Signed-off-by: Dan Carpenter Signed-off-by: Jens Axboe --- fs/io_uring.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 29565d82291f..d35b45696c73 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3075,7 +3075,7 @@ static int io_sendmsg(struct io_kiocb *req, struct io_kiocb **nxt, if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) { - if (kmsg && kmsg->iov != kmsg->fast_iov) + if (kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); return -ENOMEM; } @@ -3229,7 +3229,7 @@ static int io_recvmsg(struct io_kiocb *req, struct io_kiocb **nxt, if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) { - if (kmsg && kmsg->iov != kmsg->fast_iov) + if (kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); return -ENOMEM; } -- cgit v1.2.3-54-g00ecf From 929a3af90f0f4bd7132d83552c1a98c83f60ef7e Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 19 Feb 2020 00:19:09 +0300 Subject: io_uring: fix use-after-free by io_cleanup_req() io_cleanup_req() should be called before req->io is freed, and so shouldn't be after __io_free_req() -> __io_req_aux_free(). Also, it will be ignored for in io_free_req_many(), which use __io_req_aux_free(). Place cleanup_req() into __io_req_aux_free(). Fixes: 99bc4c38537d774 ("io_uring: fix iovec leaks") Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index d35b45696c73..6e249aa97ba3 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1260,6 +1260,9 @@ static void __io_req_aux_free(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; + if (req->flags & REQ_F_NEED_CLEANUP) + io_cleanup_req(req); + kfree(req->io); if (req->file) { if (req->flags & REQ_F_FIXED_FILE) @@ -1275,9 +1278,6 @@ static void __io_free_req(struct io_kiocb *req) { __io_req_aux_free(req); - if (req->flags & REQ_F_NEED_CLEANUP) - io_cleanup_req(req); - if (req->flags & REQ_F_INFLIGHT) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; -- cgit v1.2.3-54-g00ecf From 7143b5ac5750f404ff3a594b34fdf3fc2f99f828 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Fri, 21 Feb 2020 16:42:16 +0100 Subject: io_uring: prevent sq_thread from spinning when it should stop This patch drops 'cur_mm' before calling cond_resched(), to prevent the sq_thread from spinning even when the user process is finished. Before this patch, if the user process ended without closing the io_uring fd, the sq_thread continues to spin until the 'sq_thread_idle' timeout ends. In the worst case where the 'sq_thread_idle' parameter is bigger than INT_MAX, the sq_thread will spin forever. Fixes: 6c271ce2f1d5 ("io_uring: add submission polling") Signed-off-by: Stefano Garzarella Signed-off-by: Jens Axboe --- fs/io_uring.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6e249aa97ba3..b43467b3a8dc 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5142,6 +5142,18 @@ static int io_sq_thread(void *data) * to enter the kernel to reap and flush events. */ if (!to_submit || ret == -EBUSY) { + /* + * Drop cur_mm before scheduling, we can't hold it for + * long periods (or over schedule()). Do this before + * adding ourselves to the waitqueue, as the unuse/drop + * may sleep. + */ + if (cur_mm) { + unuse_mm(cur_mm); + mmput(cur_mm); + cur_mm = NULL; + } + /* * We're polling. If we're within the defined idle * period, then let us spin without work before going @@ -5156,18 +5168,6 @@ static int io_sq_thread(void *data) continue; } - /* - * Drop cur_mm before scheduling, we can't hold it for - * long periods (or over schedule()). Do this before - * adding ourselves to the waitqueue, as the unuse/drop - * may sleep. - */ - if (cur_mm) { - unuse_mm(cur_mm); - mmput(cur_mm); - cur_mm = NULL; - } - prepare_to_wait(&ctx->sqo_wait, &wait, TASK_INTERRUPTIBLE); -- cgit v1.2.3-54-g00ecf From c7849be9cc2dd2754c48ddbaca27c2de6d80a95d Mon Sep 17 00:00:00 2001 From: Xiaoguang Wang Date: Sat, 22 Feb 2020 14:46:05 +0800 Subject: io_uring: fix __io_iopoll_check deadlock in io_sq_thread Since commit a3a0e43fd770 ("io_uring: don't enter poll loop if we have CQEs pending"), if we already events pending, we won't enter poll loop. In case SETUP_IOPOLL and SETUP_SQPOLL are both enabled, if app has been terminated and don't reap pending events which are already in cq ring, and there are some reqs in poll_list, io_sq_thread will enter __io_iopoll_check(), and find pending events, then return, this loop will never have a chance to exit. I have seen this issue in fio stress tests, to fix this issue, let io_sq_thread call io_iopoll_getevents() with argument 'min' being zero, and remove __io_iopoll_check(). Fixes: a3a0e43fd770 ("io_uring: don't enter poll loop if we have CQEs pending") Signed-off-by: Xiaoguang Wang Signed-off-by: Jens Axboe --- fs/io_uring.c | 27 +++++++++------------------ 1 file changed, 9 insertions(+), 18 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b43467b3a8dc..de650df9ac53 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1672,11 +1672,17 @@ static void io_iopoll_reap_events(struct io_ring_ctx *ctx) mutex_unlock(&ctx->uring_lock); } -static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, - long min) +static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, + long min) { int iters = 0, ret = 0; + /* + * We disallow the app entering submit/complete with polling, but we + * still need to lock the ring to prevent racing with polled issue + * that got punted to a workqueue. + */ + mutex_lock(&ctx->uring_lock); do { int tmin = 0; @@ -1712,21 +1718,6 @@ static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, ret = 0; } while (min && !*nr_events && !need_resched()); - return ret; -} - -static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, - long min) -{ - int ret; - - /* - * We disallow the app entering submit/complete with polling, but we - * still need to lock the ring to prevent racing with polled issue - * that got punted to a workqueue. - */ - mutex_lock(&ctx->uring_lock); - ret = __io_iopoll_check(ctx, nr_events, min); mutex_unlock(&ctx->uring_lock); return ret; } @@ -5118,7 +5109,7 @@ static int io_sq_thread(void *data) */ mutex_lock(&ctx->uring_lock); if (!list_empty(&ctx->poll_list)) - __io_iopoll_check(ctx, &nr_events, 0); + io_iopoll_getevents(ctx, &nr_events, 0); else inflight = 0; mutex_unlock(&ctx->uring_lock); -- cgit v1.2.3-54-g00ecf