The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From bee749b187ac57d1faf00b2ab356ff322230fce8 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov asml.silence@gmail.com Date: Wed, 25 Nov 2020 02:19:23 +0000 Subject: [PATCH] io_uring: fix files cancellation
io_uring_cancel_files()'s task check condition mistakenly got flipped.
1. There can't be a request in the inflight list without IO_WQ_WORK_FILES, kill this check to keep the whole condition simpler. 2. Also, don't call the function for files==NULL to not do such a check, all that staff is already handled well by its counter part, __io_uring_cancel_task_requests().
With that just flip the task check.
Also, it iowq-cancels all request of current task there, don't forget to set right ->files into struct io_task_cancel.
Fixes: c1973b38bf639 ("io_uring: cancel only requests of current task") Reported-by: syzbot+c0d52d0b3c0c3ffb9525@syzkaller.appspotmail.com Signed-off-by: Pavel Begunkov 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 e66888d45778..f47de27e5125 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8688,15 +8688,14 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx, struct files_struct *files) { while (!list_empty_careful(&ctx->inflight_list)) { - struct io_task_cancel cancel = { .task = task, .files = NULL, }; + struct io_task_cancel cancel = { .task = task, .files = files }; struct io_kiocb *req; DEFINE_WAIT(wait); bool found = false;
spin_lock_irq(&ctx->inflight_lock); list_for_each_entry(req, &ctx->inflight_list, inflight_entry) { - if (req->task == task && - (req->work.flags & IO_WQ_WORK_FILES) && + if (req->task != task || req->work.identity->files != files) continue; found = true; @@ -8768,10 +8767,11 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
io_cancel_defer_files(ctx, task, files); io_cqring_overflow_flush(ctx, true, task, files); - io_uring_cancel_files(ctx, task, files);
if (!files) __io_uring_cancel_task_requests(ctx, task); + else + io_uring_cancel_files(ctx, task, files);
if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) { atomic_dec(&task->io_uring->in_idle);