From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB8772590 for ; Sun, 22 Jan 2023 15:12:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EF24C433EF; Sun, 22 Jan 2023 15:12:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1674400332; bh=xD3AYwBmm7PKmBNsYHmtr8QyoJvhojUloP4cPovuszo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CTeE5+8qEnKqytNgc5zh6tflQE9smuEJ8iKZnHvsMYxtT5vqS1sA/gB/AiGloxsR1 hzhMX/qWQsqtjZ6tjkajcacSGRQzSEMqP9BxBEnRlW/R5GnTm83MdfXKiOjY2AK6Iz RS6NpvYv/vCIp2Do9yfGaL9CXrF8zJkmRTbFaSec= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com, Jan Kara , Jens Axboe , Sasha Levin Subject: [PATCH 5.10 34/98] io_uring/rw: defer fsnotify calls to task context Date: Sun, 22 Jan 2023 16:03:50 +0100 Message-Id: <20230122150230.933049060@linuxfoundation.org> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230122150229.351631432@linuxfoundation.org> References: <20230122150229.351631432@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Jens Axboe commit b000145e9907809406d8164c3b2b8861d95aecd1 upstream. We can't call these off the kiocb completion as that might be off soft/hard irq context. Defer the calls to when we process the task_work for this request. That avoids valid complaints like: stack backtrace: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.0.0-rc6-syzkaller-00321-g105a36f3694e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_usage_bug kernel/locking/lockdep.c:3961 [inline] valid_state kernel/locking/lockdep.c:3973 [inline] mark_lock_irq kernel/locking/lockdep.c:4176 [inline] mark_lock.part.0.cold+0x18/0xd8 kernel/locking/lockdep.c:4632 mark_lock kernel/locking/lockdep.c:4596 [inline] mark_usage kernel/locking/lockdep.c:4527 [inline] __lock_acquire+0x11d9/0x56d0 kernel/locking/lockdep.c:5007 lock_acquire kernel/locking/lockdep.c:5666 [inline] lock_acquire+0x1ab/0x570 kernel/locking/lockdep.c:5631 __fs_reclaim_acquire mm/page_alloc.c:4674 [inline] fs_reclaim_acquire+0x115/0x160 mm/page_alloc.c:4688 might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook mm/slab.h:700 [inline] slab_alloc mm/slab.c:3278 [inline] __kmem_cache_alloc_lru mm/slab.c:3471 [inline] kmem_cache_alloc+0x39/0x520 mm/slab.c:3491 fanotify_alloc_fid_event fs/notify/fanotify/fanotify.c:580 [inline] fanotify_alloc_event fs/notify/fanotify/fanotify.c:813 [inline] fanotify_handle_event+0x1130/0x3f40 fs/notify/fanotify/fanotify.c:948 send_to_group fs/notify/fsnotify.c:360 [inline] fsnotify+0xafb/0x1680 fs/notify/fsnotify.c:570 __fsnotify_parent+0x62f/0xa60 fs/notify/fsnotify.c:230 fsnotify_parent include/linux/fsnotify.h:77 [inline] fsnotify_file include/linux/fsnotify.h:99 [inline] fsnotify_access include/linux/fsnotify.h:309 [inline] __io_complete_rw_common+0x485/0x720 io_uring/rw.c:195 io_complete_rw+0x1a/0x1f0 io_uring/rw.c:228 iomap_dio_complete_work fs/iomap/direct-io.c:144 [inline] iomap_dio_bio_end_io+0x438/0x5e0 fs/iomap/direct-io.c:178 bio_endio+0x5f9/0x780 block/bio.c:1564 req_bio_endio block/blk-mq.c:695 [inline] blk_update_request+0x3fc/0x1300 block/blk-mq.c:825 scsi_end_request+0x7a/0x9a0 drivers/scsi/scsi_lib.c:541 scsi_io_completion+0x173/0x1f70 drivers/scsi/scsi_lib.c:971 scsi_complete+0x122/0x3b0 drivers/scsi/scsi_lib.c:1438 blk_complete_reqs+0xad/0xe0 block/blk-mq.c:1022 __do_softirq+0x1d3/0x9c6 kernel/softirq.c:571 invoke_softirq kernel/softirq.c:445 [inline] __irq_exit_rcu+0x123/0x180 kernel/softirq.c:650 irq_exit_rcu+0x5/0x20 kernel/softirq.c:662 common_interrupt+0xa9/0xc0 arch/x86/kernel/irq.c:240 Fixes: f63cf5192fe3 ("io_uring: ensure that fsnotify is always called") Link: https://lore.kernel.org/all/20220929135627.ykivmdks2w5vzrwg@quack3/ Reported-by: syzbot+dfcc5f4da15868df7d4d@syzkaller.appspotmail.com Reported-by: Jan Kara Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- io_uring/io_uring.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index d4e017b07371..33e6e1011105 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -2702,12 +2702,6 @@ static bool io_rw_should_reissue(struct io_kiocb *req) static bool __io_complete_rw_common(struct io_kiocb *req, long res) { - if (req->rw.kiocb.ki_flags & IOCB_WRITE) { - kiocb_end_write(req); - fsnotify_modify(req->file); - } else { - fsnotify_access(req->file); - } if (res != req->result) { if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_should_reissue(req)) { @@ -2760,6 +2754,20 @@ static void __io_complete_rw(struct io_kiocb *req, long res, long res2, __io_req_complete(req, issue_flags, io_fixup_rw_res(req, res), io_put_rw_kbuf(req)); } +static void io_req_rw_complete(struct io_kiocb *req, bool *locked) +{ + struct io_rw *rw = &req->rw; + + if (rw->kiocb.ki_flags & IOCB_WRITE) { + kiocb_end_write(req); + fsnotify_modify(req->file); + } else { + fsnotify_access(req->file); + } + + io_req_task_complete(req, locked); +} + static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); @@ -2767,7 +2775,7 @@ static void io_complete_rw(struct kiocb *kiocb, long res, long res2) if (__io_complete_rw_common(req, res)) return; req->result = io_fixup_rw_res(req, res); - req->io_task_work.func = io_req_task_complete; + req->io_task_work.func = io_req_rw_complete; io_req_task_work_add(req); } -- 2.39.0