From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oa1-f77.google.com (mail-oa1-f77.google.com [209.85.160.77]) (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 067FB4B0487 for ; Sat, 15 Aug 2026 00:11:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.77 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786752698; cv=none; b=KeIM1IC+EvTIFs1p8uwZp5WfoWXl6SJ3ISPYIBqb6Dd75G7TMk37/b9CQaaBwsuoAIdAbl3UOQvyrRo+mdWv/kJesaMevsnwjIoAnjd9xmZ//GkwVM3j0NUVYNbiU6zX5uvpJKHD7/4HIiCWGOKaqwBdGXAux7+a31laJbvHdEU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786752698; c=relaxed/simple; bh=Rg0QWmt9FGxH0sq59MVWlgDGyp2/YseKWgNvxL1j5EY=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=KFq4OfZ/wOgpd551x3zmp5QUVYoTYlp0WmKcSgDhDI/oBh7rhzPf8pUReZXgR8a0VoKXGM07vEjRwTQc3ALDbCceTM/lDdKFz2lo5JLeKPN6JzVf+sTkaVmoGy1BZ8ZD86ugXOJ2akKsblRlceE/WINf98/fqYVLC9MFwcuI184= 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=209.85.160.77 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-oa1-f77.google.com with SMTP id 586e51a60fabf-44899f99756so2037256fac.2 for ; Fri, 14 Aug 2026 17:11:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786752696; x=1787357496; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=0pfHBZkP+bol7AU9NvnslyqRVXphOe4m7EmVJ4GVGq0=; b=DnFEGSJHuocSQ7ZE0/gz4xC4zmG/UTczCJo7A7juKONcLBgKjMMF2SZOyKXWYNVdFg RLybB/Kptn49XBNT1yzQHNdv6YZiXoaL6AaAuunnPM1ViSlSHaZdFQnHH5RyOlZXLoSM NjrmM2ECbR7BN1pxx/uueO4ri4q+GOcdX/uwXDKbVaZlzLoZdkfGSHDCflUKD6aa1sw2 frgxCH+T945Qvbn8joq4OxQvKT46KBGxe9H2kcOm5kGjSyYXSnjmZTnjRuk+6rm79xsB ko+eHi2POcA8LMr54bZhn8VQer9r1l6CwAbiiw0vwDEFPs/ZBK/S6VzW4JtW/jkDGE5k BtIQ== X-Forwarded-Encrypted: i=1; AHgh+RqgOPDC8mElskmsrsOdx6VVwOTn//GdIKaY/+FXlwp/swsX63SidHNPNS676urvjkKswOWxsx1Tvmw6F2M=@vger.kernel.org X-Gm-Message-State: AOJu0YwO1MytUgGlSip577OM+PZaTgJ/3MUR3o8qXma7KqJMEvOcr0xC pLTaHCgXco0JOgRp2bO7/X3GF7aziLej+zgcVWKZkFOB2aDj5bVchgFSKelq01auACQqvm++NNF ysLfsCuThy38OW9JP6ax2Ot0hc0vEyDLGINvkVJP35fnda4iy0AMH7SOa5tw= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:813:b0:6b0:4fbc:aecf with SMTP id 006d021491bc7-6b0d68b2455mr7133755eaf.24.1786752695855; Fri, 14 Aug 2026 17:11:35 -0700 (PDT) Date: Fri, 14 Aug 2026 17:11:35 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7faeb7.432fbecc.3db7aa.015d.GAE@google.com> Subject: [syzbot] [autofs?] possible deadlock in anon_pipe_write (3) From: syzbot To: autofs@vger.kernel.org, linux-kernel@vger.kernel.org, raven@themaw.net, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: d58772d8520c Merge tag 'regmap-fix-v7.2-rc7' of git://git... git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=106812c6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=8a233ed2ce9a8096 dashboard link: https://syzkaller.appspot.com/bug?extid=c36cbd4737e4508de101 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 userspace arch: i386 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d58772d8.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a4e864f7b043/vmlinux-d58772d8.xz kernel image: https://storage.googleapis.com/syzbot-assets/f485f29307dc/bzImage-d58772d8.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+c36cbd4737e4508de101@syzkaller.appspotmail.com ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Tainted: G L ------------------------------------------------------ syz.0.717/10076 is trying to acquire lock: ffff8880517dd860 (&pipe->mutex){+.+.}-{4:4}, at: anon_pipe_write+0x25e/0x1d90 fs/pipe.c:553 but task is already holding lock: ffff88802aeb3938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] ffff88802aeb3938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->pipe_mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 autofs_write fs/autofs/waitq.c:55 [inline] autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 kern_path+0x37/0x50 fs/namei.c:3036 lookup_bdev+0xd8/0x280 block/bdev.c:1208 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #1 (&of->mutex){+.+.}-{4:4}: lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 iter_file_splice_write+0x830/0x10b0 fs/splice.c:736 do_splice_from fs/splice.c:936 [inline] do_splice+0x109c/0x1f90 fs/splice.c:1349 __do_splice+0x33b/0x370 fs/splice.c:1431 __do_sys_splice fs/splice.c:1634 [inline] __se_sys_splice fs/splice.c:1616 [inline] __ia32_sys_splice+0x189/0x250 fs/splice.c:1616 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e -> #0 (&pipe->mutex){+.+.}-{4:4}: check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 anon_pipe_write+0x25e/0x1d90 fs/pipe.c:553 __kernel_write_iter+0x6bb/0x930 fs/read_write.c:621 __kernel_write+0xf6/0x140 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x50d/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 kern_path+0x37/0x50 fs/namei.c:3036 lookup_bdev+0xd8/0x280 block/bdev.c:1208 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Chain exists of: &pipe->mutex --> &of->mutex --> &sbi->pipe_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->pipe_mutex); lock(&of->mutex); lock(&sbi->pipe_mutex); lock(&pipe->mutex); *** DEADLOCK *** 5 locks held by syz.0.717/10076: #0: ffff8880275d35f0 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1259 #1: ffff88802ac8e450 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:739 #2: ffff8880721bcc80 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x2c2/0x5f0 fs/kernfs/file.c:336 #3: ffff88801d35e5a8 (kn->active#85){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline] #3: ffff88801d35e5a8 (kn->active#85){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x332/0x5f0 fs/kernfs/file.c:337 #4: ffff88802aeb3938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_write fs/autofs/waitq.c:55 [inline] #4: ffff88802aeb3938 (&sbi->pipe_mutex){+.+.}-{4:4}, at: autofs_notify_daemon+0x4f8/0xd90 fs/autofs/waitq.c:164 stack backtrace: CPU: 2 UID: 0 PID: 10076 Comm: syz.0.717 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_circular_bug.cold+0x178/0x1c7 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add+0xeb/0xe60 kernel/locking/lockdep.c:3165 check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x136c/0x1a40 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x1b9/0x370 kernel/locking/lockdep.c:5825 __mutex_lock_common kernel/locking/mutex.c:646 [inline] __mutex_lock+0x1a4/0x1bd0 kernel/locking/mutex.c:821 anon_pipe_write+0x25e/0x1d90 fs/pipe.c:553 __kernel_write_iter+0x6bb/0x930 fs/read_write.c:621 __kernel_write+0xf6/0x140 fs/read_write.c:641 autofs_write fs/autofs/waitq.c:57 [inline] autofs_notify_daemon+0x50d/0xd90 fs/autofs/waitq.c:164 autofs_wait+0x10fd/0x1b50 fs/autofs/waitq.c:426 autofs_mount_wait+0x132/0x3b0 fs/autofs/root.c:256 autofs_d_automount+0x490/0x950 fs/autofs/root.c:410 follow_automount fs/namei.c:1565 [inline] __traverse_mounts+0x1b9/0x8a0 fs/namei.c:1618 traverse_mounts fs/namei.c:1647 [inline] handle_mounts fs/namei.c:1749 [inline] step_into_slowpath+0xb7e/0xf90 fs/namei.c:2104 step_into fs/namei.c:2152 [inline] walk_component fs/namei.c:2288 [inline] lookup_last fs/namei.c:2789 [inline] path_lookupat+0x58b/0xc40 fs/namei.c:2813 filename_lookup+0x202/0x590 fs/namei.c:2842 kern_path+0x37/0x50 fs/namei.c:3036 lookup_bdev+0xd8/0x280 block/bdev.c:1208 resume_store+0x1d6/0x460 kernel/power/hibernate.c:1278 kobj_attr_store+0x58/0x80 lib/kobject.c:840 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline] __do_fast_syscall_32+0xe7/0x970 arch/x86/entry/syscall_32.c:307 do_fast_syscall_32+0x32/0x70 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf706efec Code: Unable to access opcode bytes at 0xf706efc2. RSP: 002b:00000000f543c50c EFLAGS: 00000292 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 0000000080000040 RDX: 0000000000000012 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 PM: Image not found (code -6) --- 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. 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