From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 84466C433FE for ; Fri, 26 Nov 2021 12:42:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377603AbhKZMph (ORCPT ); Fri, 26 Nov 2021 07:45:37 -0500 Received: from mail-io1-f70.google.com ([209.85.166.70]:40712 "EHLO mail-io1-f70.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377495AbhKZMnh (ORCPT ); Fri, 26 Nov 2021 07:43:37 -0500 Received: by mail-io1-f70.google.com with SMTP id d12-20020a0566022d4c00b005ebda1035b1so11637700iow.7 for ; Fri, 26 Nov 2021 04:40:24 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:date:message-id:subject:from:to; bh=J9pKVZSmKtwpuPTSe05C26OqSqmxQieJZ73iDt5ItI0=; b=7lsXz9HoGLYYfpXQa4q8EeTHJAG6DeYwpdt4aHTQTXAoS+jtUs2wmOHJ+oOpRDbWjC 5nkR4t1kfOVLJURJYFIUnYiv4hzDcw3oZbG26/l3XuVxrfb7HiNgTpRZPtQagCCQa4Zs 9hgSJ3I44l1a9VhC/lqpuRiqVRqW9LjGuDoa7F+GzPchiS2qcY+6gIFd1GdOxF37VS/q totmFKm34NWqV+hyqQIawFnjICuhQvKIDvk3ZqHSayc2PmaxvWt3oAAoOvSslLOkTVF9 QOd9jQs0w2VqmEpTDCUAIYEbZ7/6R+rYoE5X6Z1LEBhlzAhThBeKy3jOIuGVxvIcFeOs j7qA== X-Gm-Message-State: AOAM5325RmKZrPZbTHzqpfJVSh5oCAGu7kDuJxSzjYclWi+z5RWMDorK XZIc/GmmzELnD/1P9/ucnICGvhz6BTxmk9YNfMLDEA+xwN2N X-Google-Smtp-Source: ABdhPJwydALsw0AUDvn4BmRA+g86FQGhU3lx8A/9xuaGrBTfSq1Twc1ieT2/aFzMEui8c6EGkmhxQqbuF8ILwkHql9cxc9nYpkfu MIME-Version: 1.0 X-Received: by 2002:a6b:3b49:: with SMTP id i70mr34689542ioa.12.1637930424017; Fri, 26 Nov 2021 04:40:24 -0800 (PST) Date: Fri, 26 Nov 2021 04:40:24 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <0000000000001729c705d1b065f7@google.com> Subject: [syzbot] possible deadlock in __io_commit_cqring_flush From: syzbot To: asml.silence@gmail.com, axboe@kernel.dk, io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Hello, syzbot found the following issue on: HEAD commit: a4849f6000e2 Merge tag 'drm-fixes-2021-11-26' of git://ano.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10d5f726b00000 kernel config: https://syzkaller.appspot.com/x/.config?x=75f05fb8d1a152d3 dashboard link: https://syzkaller.appspot.com/bug?extid=ff49a3059d49b0ca0eec compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+ff49a3059d49b0ca0eec@syzkaller.appspotmail.com ============================================ WARNING: possible recursive locking detected 5.16.0-rc2-syzkaller #0 Not tainted -------------------------------------------- syz-executor.1/8766 is trying to acquire lock: ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline] ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: io_flush_timeouts fs/io_uring.c:1587 [inline] ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: __io_commit_cqring_flush+0x108/0x50d fs/io_uring.c:1618 but task is already holding lock: ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline] ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: io_poll_remove_all+0x50/0x235 fs/io_uring.c:5702 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&ctx->timeout_lock); lock(&ctx->timeout_lock); *** DEADLOCK *** May be due to missing lock nesting notation 2 locks held by syz-executor.1/8766: #0: ffff888096b573d8 (&ctx->completion_lock#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:349 [inline] #0: ffff888096b573d8 (&ctx->completion_lock#2){+.+.}-{2:2}, at: io_poll_remove_all+0x48/0x235 fs/io_uring.c:5701 #1: ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: spin_lock_irq include/linux/spinlock.h:374 [inline] #1: ffff888096b57418 (&ctx->timeout_lock){+.+.}-{2:2}, at: io_poll_remove_all+0x50/0x235 fs/io_uring.c:5702 stack backtrace: CPU: 0 PID: 8766 Comm: syz-executor.1 Not tainted 5.16.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_deadlock_bug kernel/locking/lockdep.c:2956 [inline] check_deadlock kernel/locking/lockdep.c:2999 [inline] validate_chain kernel/locking/lockdep.c:3788 [inline] __lock_acquire.cold+0x149/0x3ab kernel/locking/lockdep.c:5027 lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:119 [inline] _raw_spin_lock_irq+0x32/0x50 kernel/locking/spinlock.c:170 spin_lock_irq include/linux/spinlock.h:374 [inline] io_flush_timeouts fs/io_uring.c:1587 [inline] __io_commit_cqring_flush+0x108/0x50d fs/io_uring.c:1618 io_commit_cqring fs/io_uring.c:1626 [inline] io_poll_remove_one fs/io_uring.c:5684 [inline] io_poll_remove_one.cold+0xd/0x12 fs/io_uring.c:5674 io_poll_remove_all+0x1af/0x235 fs/io_uring.c:5709 io_ring_ctx_wait_and_kill+0x1cc/0x322 fs/io_uring.c:9534 io_uring_release+0x42/0x46 fs/io_uring.c:9554 __fput+0x286/0x9f0 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:164 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:175 [inline] exit_to_user_mode_prepare+0x27e/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f087b422ae9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0878977188 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: 0000000020ffa000 RBX: 00007f087b536020 RCX: 00007f087b422ae9 RDX: 0000000003000001 RSI: 0000000000004000 RDI: 0000000020ffa000 RBP: 00007f087b47cf6d R08: 0000000000000003 R09: 0000000010000000 R10: 0000000000000012 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe7626bd9f R14: 00007f0878977300 R15: 0000000000022000 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.