From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f80.google.com (mail-ot1-f80.google.com [209.85.210.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D0BF2F7AAB for ; Mon, 29 Dec 2025 11:10:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767006624; cv=none; b=thJinka1+C4OmBYiMx2Xf/Xj6YW/QDxdLCUqVMq1AQoWr9v5lKb1CSaULVN2L8S/CehdPooAtLlTuTZ4hklkcok+5JPA5U7Tuof8GPLbZie87hM3Ftzn79uV7a6KbSt2a6Rnv1iYXOWTjbJmdT/KXs4uCvzcymwvIM2ekARre04= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767006624; c=relaxed/simple; bh=yWwG4b3KjNCTp/4LIl1u4VHdMYv1oKH9APJ1N5QE+iM=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=jJMBOdGc25MRIFoS1Ce8GxadyEyUuZHi6dYLpWeEIqmTcHJEllCeZDlcnQcQRu5mkNowR7LJ8EOckQJLSvdfkLWqXYFBQzvVTCzv+MSCcr3mTGl+fKPVLpagXdykbrXvhYB2QvqRgo9VWEFffQD/TtwUiK1RXdxm7Nhb86pFi4M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.80 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f80.google.com with SMTP id 46e09a7af769-7c7595cde21so20126267a34.2 for ; Mon, 29 Dec 2025 03:10:22 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767006621; x=1767611421; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=xVswuzew5+X9r2+dvHCiCbbY0WwOc10DsheFTZteNvg=; b=t31GtMsG8JiwvhXLUQCSq/5lSBg94pHrCeeEUDu847M6fRZa2AQKD6ggkItnSul+Qt RAzFVQRiEz/gUhS0gcNQ5s5qO1JamqAPo43Ddl/i6toWLc2mwaen4wHA/3tOH41c1AA2 skOUZlvmHoImmK4fU1jCEN8V5RYge70UuyoZJgdj15pCEfGj0hJQ4i60FVpyApqXH7AD EAXsV8zI5AeL6p1ySaW/3aJzOHeyW6wJDz/STlI2Rz+Afp6X0z1zV2lGn93QIqiI4vIu I5KbKQcsbQSdC+l2MVYjMp1xFmbaSa/zEC1Ujn7rH+jmMw77/iwky1oQPc6tLtiGPVaA BP/w== X-Forwarded-Encrypted: i=1; AJvYcCW6cKpuHROsOsJSMGmIlHg0O3XKwneC/R/VtUk0o0e9IAsh9Q9buTqpsCN33pM7yXZzv00y4po5cuPo+rc=@vger.kernel.org X-Gm-Message-State: AOJu0Yx/a0hVQTCjCmfsaTFfqqyWqhCSxYfyoauUSWU3ITC1uf17svxY BbUtaw3p4QzYc2QD2ZAvfw5Hn6nZQaA5W3Etdon5s0y/QLnw7/2jXklCUe9/2x34Ty4FMTqvtvD Qrsd7iJ12CtL4DrRdTQjJzds/CgFEYnOViiKdTAObFq8Ri2JD5oeAl5DIR+0= X-Google-Smtp-Source: AGHT+IHXULmBtCPF6AOvzg7RVKTWxVRR9Q12mp+YEf8zqQcWbxfGVClqRWwChm8VkdoLjg9gJjdt6PdoiOL9aARzkK/8H6ivaV5p Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1507:b0:65c:f046:bb72 with SMTP id 006d021491bc7-65d0e932cccmr14990830eaf.7.1767006621621; Mon, 29 Dec 2025 03:10:21 -0800 (PST) Date: Mon, 29 Dec 2025 03:10:21 -0800 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6952619d.050a0220.3b1790.0009.GAE@google.com> Subject: [syzbot] [fs?] possible deadlock in mnt_want_write (7) From: syzbot To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 9094662f6707 Merge tag 'ata-6.19-rc2' of git://git.kernel... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17c70b1a580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a94030c847137a18 dashboard link: https://syzkaller.appspot.com/bug?extid=29e107ef90787b28d121 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/df3fce69c21a/disk-9094662f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/182b66a92309/vmlinux-9094662f.xz kernel image: https://storage.googleapis.com/syzbot-assets/0cccba3c045d/bzImage-9094662f.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+29e107ef90787b28d121@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.647/8372 is trying to acquire lock: ffff8880259d8420 (sb_writers#3){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 but task is already holding lock: ffff88803403a0a8 (&ctx->uring_lock){+.+.}-{4:4}, at: __do_sys_io_uring_enter io_uring/io_uring.c:3279 [inline] ffff88803403a0a8 (&ctx->uring_lock){+.+.}-{4:4}, at: __se_sys_io_uring_enter+0x2d5/0x2b60 io_uring/io_uring.c:3219 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ctx->uring_lock){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 io_uring_del_tctx_node+0xf0/0x2c0 io_uring/tctx.c:179 io_uring_clean_tctx+0xd4/0x1a0 io_uring/tctx.c:195 io_uring_cancel_generic+0x6ca/0x7d0 io_uring/cancel.c:646 io_uring_task_cancel include/linux/io_uring.h:24 [inline] begin_new_exec+0x10ed/0x2440 fs/exec.c:1131 load_elf_binary+0x9f8/0x2d70 fs/binfmt_elf.c:1010 search_binary_handler fs/exec.c:1669 [inline] exec_binprm fs/exec.c:1701 [inline] bprm_execve+0x92e/0x1400 fs/exec.c:1753 do_execveat_common+0x510/0x6a0 fs/exec.c:1859 do_execveat fs/exec.c:1944 [inline] __do_sys_execveat fs/exec.c:2018 [inline] __se_sys_execveat fs/exec.c:2012 [inline] __x64_sys_execveat+0xc4/0xe0 fs/exec.c:2012 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #1 (&sig->cred_guard_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:614 [inline] __mutex_lock+0x187/0x1350 kernel/locking/mutex.c:776 proc_pid_attr_write+0x547/0x630 fs/proc/base.c:2837 vfs_write+0x27e/0xb30 fs/read_write.c:684 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (sb_writers#3){.+.+}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs/super.h:125 mnt_want_write+0x41/0x90 fs/namespace.c:499 open_last_lookups fs/namei.c:4529 [inline] path_openat+0xadd/0x3dd0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 io_openat2+0x3e0/0x5c0 io_uring/openclose.c:143 __io_issue_sqe+0x181/0x4b0 io_uring/io_uring.c:1792 io_issue_sqe+0x165/0x1060 io_uring/io_uring.c:1815 io_queue_sqe io_uring/io_uring.c:2042 [inline] io_submit_sqe io_uring/io_uring.c:2320 [inline] io_submit_sqes+0xbf4/0x2140 io_uring/io_uring.c:2434 __do_sys_io_uring_enter io_uring/io_uring.c:3280 [inline] __se_sys_io_uring_enter+0x2e0/0x2b60 io_uring/io_uring.c:3219 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: sb_writers#3 --> &sig->cred_guard_mutex --> &ctx->uring_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ctx->uring_lock); lock(&sig->cred_guard_mutex); lock(&ctx->uring_lock); rlock(sb_writers#3); *** DEADLOCK *** 1 lock held by syz.0.647/8372: #0: ffff88803403a0a8 (&ctx->uring_lock){+.+.}-{4:4}, at: __do_sys_io_uring_enter io_uring/io_uring.c:3279 [inline] #0: ffff88803403a0a8 (&ctx->uring_lock){+.+.}-{4:4}, at: __se_sys_io_uring_enter+0x2d5/0x2b60 io_uring/io_uring.c:3219 stack backtrace: CPU: 0 UID: 0 PID: 8372 Comm: syz.0.647 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 print_circular_bug+0x2e2/0x300 kernel/locking/lockdep.c:2043 check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x15a6/0x2cf0 kernel/locking/lockdep.c:5237 lock_acquire+0x107/0x340 kernel/locking/lockdep.c:5868 percpu_down_read_internal include/linux/percpu-rwsem.h:53 [inline] percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline] __sb_start_write include/linux/fs/super.h:19 [inline] sb_start_write+0x4d/0x1c0 include/linux/fs/super.h:125 mnt_want_write+0x41/0x90 fs/namespace.c:499 open_last_lookups fs/namei.c:4529 [inline] path_openat+0xadd/0x3dd0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 io_openat2+0x3e0/0x5c0 io_uring/openclose.c:143 __io_issue_sqe+0x181/0x4b0 io_uring/io_uring.c:1792 io_issue_sqe+0x165/0x1060 io_uring/io_uring.c:1815 io_queue_sqe io_uring/io_uring.c:2042 [inline] io_submit_sqe io_uring/io_uring.c:2320 [inline] io_submit_sqes+0xbf4/0x2140 io_uring/io_uring.c:2434 __do_sys_io_uring_enter io_uring/io_uring.c:3280 [inline] __se_sys_io_uring_enter+0x2e0/0x2b60 io_uring/io_uring.c:3219 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcffab8f749 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcffb980038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 00007fcffade5fa0 RCX: 00007fcffab8f749 RDX: 0000000000000000 RSI: 0000000000003516 RDI: 0000000000000009 RBP: 00007fcffac13f91 R08: 0000000000000000 R09: 00000000fffffdcf R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fcffade6038 R14: 00007fcffade5fa0 R15: 00007fcffaf0fa28 --- 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. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup