From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f206.google.com (mail-il1-f206.google.com [209.85.166.206]) (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 22418269817 for ; Sat, 5 Jul 2025 03:20:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751685636; cv=none; b=L7zE582+FjCLMiSjjWay5QcQtOhuzcZX7rjH+U2cl3YY9VBxrwePkGwMj4jrdXzpyYrHX7OZxNoIY8AAzKMlunTxANQ9rM0nrLj3hHCqHf5F5n7kCdxIaEPgw7kdtaJUhzjX2UNVLLjXRNnHANWjW0xwwEie9/q3ZYJg/qcPu40= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751685636; c=relaxed/simple; bh=zZwDXQap667ELnegP7wTGLkBneiHcdIV4IyHvMHsMh0=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=cJSnfC03ftp5i8vwGW7pROueZLSWPp9ED/rBZikCydTvknXW6g8q1CbrQT0XnlGwyzqW7uLtp8n6i548BPURRrVx0FHcHtuNQFcVtXwEcdokWHoFO9URRWbKA1ucBQi1cJKjL+aHilR71JSf6/60XLA5AN+qyFzFTGiUQLwYkRk= 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=209.85.166.206 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-il1-f206.google.com with SMTP id e9e14a558f8ab-3df40226ab7so32669815ab.0 for ; Fri, 04 Jul 2025 20:20:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1751685634; x=1752290434; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=nKt1RwcKjdMcd7EsDv9hpf69VqnWr85XcRCar4AQMZ8=; b=gM8gOHCsHtP8pcn6WDcn6XZcxgp1ZTjz9zETB9rvNgBZu3Rxtvp46NQerGDcm3GCL2 BA19lOeoimeAd30QGOQETnClL9EqEyEt8Ehnjr63hvGk2eo9QZHzlhxIQlX6kG86MyXz hNWFHxz8OnyYhnJY68s2Bpic9stQl5jKIkZASUC61FzStqZzF1wEaYk42sC2MOjvdcbI VYfxfGxPcGMTT/lkBF+FRdqknQN08rsImbEbAWk3SZvNgmBxjWgEb4dKJjdeeg7H6CFa dV4RRHo8eUnzUq4W8mv+KCYgAx+PjgBUXc1rRz65zjlomNFzIwbkkNLDMttNKmqMCUci iv2g== X-Forwarded-Encrypted: i=1; AJvYcCUgxg7i1AB8fBvHVzgY92Gez4kAa97RJBWNpvQ+LD77Vb/NDkYY8gZ22jc6ZzYmHTY790+5K9IKhAc8LRg=@vger.kernel.org X-Gm-Message-State: AOJu0YxgiDshoouV/zsTVCvYgHX3q4Q3AnOZdItWXjsp7u/Gkvz0Xo6x V9lzOn+KSlaXqHg8EqkQ+EllRNeFVwNkxvcJCQPDWem4T/4tAoJoj52n7DAfhzjJZSNU8O0Zk66 s2s1E+uL0pQTv6/vL0dVJEI7YW9nNTtpMf5oH2ieacxvdo5M/zwro9nPYVmQ= X-Google-Smtp-Source: AGHT+IEt0sFGRwFvBLeNL/8AZA4SWCKa/D207JDFHLCrI0TTfNhMrqrxt7NKFuB414/EOhzd8jQaf69hA6qaE3PqdmhEmS1zs97S Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:1a85:b0:3dc:87c7:a5a6 with SMTP id e9e14a558f8ab-3e13ee8487dmr10058605ab.4.1751685634275; Fri, 04 Jul 2025 20:20:34 -0700 (PDT) Date: Fri, 04 Jul 2025 20:20:34 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68689a02.a00a0220.c7b3.002d.GAE@google.com> Subject: [syzbot] [kernel?] possible deadlock in posix_clock_unregister From: syzbot To: anna-maria@linutronix.de, frederic@kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tglx@linutronix.de Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: c435a4f487e8 Merge tag 'riscv-for-linus-6.16-rc5' of git:/.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1563548c580000 kernel config: https://syzkaller.appspot.com/x/.config?x=9887aa986c36cc50 dashboard link: https://syzkaller.appspot.com/bug?extid=7cfb66a237c4a5fb22ad compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/0f92f50c3eac/disk-c435a4f4.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/d15feed2dd9a/vmlinux-c435a4f4.xz kernel image: https://storage.googleapis.com/syzbot-assets/74b4738b6bd9/bzImage-c435a4f4.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+7cfb66a237c4a5fb22ad@syzkaller.appspotmail.com ptp ptp0: delete virtual clock ptp16 ====================================================== WARNING: possible circular locking dependency detected 6.16.0-rc4-syzkaller-00286-gc435a4f487e8 #0 Not tainted ------------------------------------------------------ syz.0.689/7737 is trying to acquire lock: ffff8880356a4130 (&clk->rwsem){++++}-{4:4}, at: posix_clock_unregister+0x4d/0xd0 kernel/time/posix-clock.c:184 but task is already holding lock: ffff88814bd10868 (&ptp->n_vclocks_mux){+.+.}-{4:4}, at: n_vclocks_store+0xf1/0x6d0 drivers/ptp/ptp_sysfs.c:215 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&ptp->n_vclocks_mux){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:602 [inline] __mutex_lock+0x199/0xb90 kernel/locking/mutex.c:747 ptp_vclock_in_use drivers/ptp/ptp_private.h:113 [inline] ptp_vclock_in_use drivers/ptp/ptp_private.h:99 [inline] ptp_clock_freerun drivers/ptp/ptp_private.h:130 [inline] ptp_clock_freerun drivers/ptp/ptp_private.h:125 [inline] ptp_clock_adjtime+0x527/0x760 drivers/ptp/ptp_clock.c:125 pc_clock_adjtime+0x118/0x1e0 kernel/time/posix-clock.c:239 do_clock_adjtime kernel/time/posix-timers.c:1162 [inline] __do_sys_clock_adjtime+0x175/0x290 kernel/time/posix-timers.c:1174 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&clk->rwsem){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 down_write+0x92/0x200 kernel/locking/rwsem.c:1577 posix_clock_unregister+0x4d/0xd0 kernel/time/posix-clock.c:184 ptp_clock_unregister+0x14f/0x250 drivers/ptp/ptp_clock.c:432 ptp_vclock_unregister+0x11a/0x160 drivers/ptp/ptp_vclock.c:228 unregister_vclock+0x108/0x1a0 drivers/ptp/ptp_sysfs.c:177 device_for_each_child_reverse+0x133/0x1a0 drivers/base/core.c:4051 n_vclocks_store+0x4b6/0x6d0 drivers/ptp/ptp_sysfs.c:241 dev_attr_store+0x55/0x80 drivers/base/core.c:2440 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6c7/0x1150 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ptp->n_vclocks_mux); lock(&clk->rwsem); lock(&ptp->n_vclocks_mux); lock(&clk->rwsem); *** DEADLOCK *** 5 locks held by syz.0.689/7737: #0: ffff88803578b7b8 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1217 #1: ffff88803704c428 (sb_writers#7){.+.+}-{0:0}, at: ksys_write+0x12a/0x250 fs/read_write.c:738 #2: ffff888033abf488 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x28f/0x510 fs/kernfs/file.c:325 #3: ffff88814bf00d28 (kn->active#60){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x2b2/0x510 fs/kernfs/file.c:326 #4: ffff88814bd10868 (&ptp->n_vclocks_mux){+.+.}-{4:4}, at: n_vclocks_store+0xf1/0x6d0 drivers/ptp/ptp_sysfs.c:215 stack backtrace: CPU: 1 UID: 0 PID: 7737 Comm: syz.0.689 Not tainted 6.16.0-rc4-syzkaller-00286-gc435a4f487e8 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x350 kernel/locking/lockdep.c:2046 check_noncircular+0x14c/0x170 kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x126f/0x1c90 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x179/0x350 kernel/locking/lockdep.c:5828 down_write+0x92/0x200 kernel/locking/rwsem.c:1577 posix_clock_unregister+0x4d/0xd0 kernel/time/posix-clock.c:184 ptp_clock_unregister+0x14f/0x250 drivers/ptp/ptp_clock.c:432 ptp_vclock_unregister+0x11a/0x160 drivers/ptp/ptp_vclock.c:228 unregister_vclock+0x108/0x1a0 drivers/ptp/ptp_sysfs.c:177 device_for_each_child_reverse+0x133/0x1a0 drivers/base/core.c:4051 n_vclocks_store+0x4b6/0x6d0 drivers/ptp/ptp_sysfs.c:241 dev_attr_store+0x55/0x80 drivers/base/core.c:2440 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x354/0x510 fs/kernfs/file.c:334 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x6c7/0x1150 fs/read_write.c:686 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2aab98e929 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:00007f2aa97f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f2aabbb5fa0 RCX: 00007f2aab98e929 RDX: 000000000000fdef RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007f2aaba10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2aabbb5fa0 R15: 00007ffc2d8b7958 ptp ptp0: delete virtual clock ptp15 ptp ptp0: delete virtual clock ptp14 ptp ptp0: delete virtual clock ptp13 ptp ptp0: delete virtual clock ptp12 ptp ptp0: delete virtual clock ptp11 ptp ptp0: delete virtual clock ptp10 ptp ptp0: delete virtual clock ptp9 ptp ptp0: delete virtual clock ptp8 ptp ptp0: delete virtual clock ptp7 ptp ptp0: delete virtual clock ptp6 ptp ptp0: delete virtual clock ptp5 ptp ptp0: delete virtual clock ptp4 ptp ptp0: guarantee physical clock free running --- 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