From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) (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 242346F06B for ; Sat, 30 Aug 2025 03:03:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.200 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756522987; cv=none; b=chH4H6CMUzpbqrIJEu3QBSAEBx13QL7hDmW4OIqagaLoN4BkIl4ma8A0M2CTVebiv0/+SyenjBEEAdN80t34KFTDxNV4e+yZC2PsuFnleoNJK/FxWg2gOh/iM5kGwLGF/4Xnk+URe6xFDf4p2kp59vOg6K+pl/m8NHPfVShwRH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756522987; c=relaxed/simple; bh=+xWXUXb2F584KaDlAB/QkQb/NkoZ+2wwvbauqbihPKQ=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=Yi1pkw0UYL70jraRorrq7DreafZX+wYo3abLo7auXjPnILU/5moxB7pA+axTadiJnSMi3O7zThZeiA2o/PGCUKHok94cMGn3qillRaVsJIYwtddXN8T7ndxGtNSNwVvLcQ1fdb7pneF1YPk37kbtTC5qPbdGrs2XUeg3krgAyTI= 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=209.85.166.200 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-f200.google.com with SMTP id e9e14a558f8ab-3ed0ba44c8fso32458255ab.0 for ; Fri, 29 Aug 2025 20:03:05 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756522985; x=1757127785; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=UHQEpGqFkvxwu8Uv/g7zCnBjm1+Wez0oY4H7G674t98=; b=aa1AYd3vsGZt04EcfE1QrkJIgL9fy9AWy9rEvYPSdq8ZMHHCg8KM35v8/cHWsnW0dk 0BB/wdLazXuaKhpl8uvuX/mick8G3xD1oJ22cmrnvKfn6y1N6KODJjDv5e1QTUmdjSYd FGdRaDMGmAgGfQaXWBCx5aW7cE3tS+h+zWHYWg0r71CgX1oSJWDNOd00khGuOfev0ivT a8gtPMDwUPkZ3WRqjyE5Djk1RkM/l02FRm4mWV1HmPblfpVmmIBBCnhzAxU1yb6rf1Zb 7B5SDKDjSyaX54Q0srQvaCROJ+AgZlU/0SiY9oQu6CX9rdCF/dTIlaHnc3wh+IeYd8aX m83Q== X-Forwarded-Encrypted: i=1; AJvYcCXC9ITR4iCO3hESeOMGnQXC3UcatFCCsBLIWU6RUiU9be+caz1Yb4BaERG1DH5DdsV1kj6614onc8E1ZiI=@vger.kernel.org X-Gm-Message-State: AOJu0YzG+tjpUIBB7oPXQtzhEzuKMMaPlxoMG0Xy+WOh////eTpz0Gr/ 2l0E3Go3x5mI5TGezg9KzwligFeD5S7LcNiircyZrMWW1YondgTioCpSjw4qyBxvWKI+fPfqzxO ibEmIlclqUoqAs1uMaeTyb7sMXjWcv2In2YbjKBiGVIBtmq8x49jcI9jh+Wk= X-Google-Smtp-Source: AGHT+IEhRZOQ/7O4PLMbB/vSO+4iXYkbFhvOW6jP0wd6O0PjNTT2nP5rg5UAC03X0DaceIkOKgP9HB726OkFNMsNBBixu3ZGEkLG Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:1a2b:b0:3ec:6e58:beb5 with SMTP id e9e14a558f8ab-3f3ffda2ecamr21128805ab.3.1756522985190; Fri, 29 Aug 2025 20:03:05 -0700 (PDT) Date: Fri, 29 Aug 2025 20:03:05 -0700 In-Reply-To: <20250830004549.6070-1-hdanton@sina.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68b269e9.a00a0220.1337b0.001f.GAE@google.com> Subject: Re: [syzbot] [sound?] possible deadlock in __snd_pcm_lib_xfer (2) From: syzbot To: hdanton@sina.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: possible deadlock in __snd_pcm_lib_xfer ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.46/6843 is trying to acquire lock: ffff8880b8823d90 ((softirq_ctrl.lock)){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline] ffff8880b8823d90 ((softirq_ctrl.lock)){+.+.}-{3:3}, at: __local_bh_disable_ip+0x264/0x400 kernel/softirq.c:168 but task is already holding lock: ffff88814ccb7150 (&group->lock#2){+.+.}-{3:3}, at: __snd_pcm_lib_xfer+0x386/0x1ce0 sound/core/pcm_lib.c:2319 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&group->lock#2){+.+.}-{3:3}: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868 rt_spin_lock+0x88/0x2c0 kernel/locking/spinlock_rt.c:56 spin_lock include/linux/spinlock_rt.h:44 [inline] _snd_pcm_stream_lock_irqsave+0x7c/0xa0 sound/core/pcm_native.c:171 class_pcm_stream_lock_irqsave_constructor include/sound/pcm.h:682 [inline] snd_pcm_period_elapsed+0x1e/0x80 sound/core/pcm_lib.c:1938 dummy_hrtimer_callback+0x80/0x180 sound/drivers/dummy.c:386 __run_hrtimer kernel/time/hrtimer.c:1763 [inline] __hrtimer_run_queues+0x590/0xda0 kernel/time/hrtimer.c:1829 hrtimer_run_softirq+0x1a3/0x2e0 kernel/time/hrtimer.c:1847 handle_softirqs+0x22c/0x710 kernel/softirq.c:579 __do_softirq kernel/softirq.c:613 [inline] run_ktimerd+0xcf/0x190 kernel/softirq.c:1043 smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 -> #0 ((softirq_ctrl.lock)){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385 __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889 __local_bh_enable_ip+0x10c/0x270 kernel/softirq.c:228 hrtimer_cancel+0x39/0x60 kernel/time/hrtimer.c:1491 dummy_hrtimer_stop+0xcf/0x100 sound/drivers/dummy.c:410 snd_pcm_do_stop+0x12a/0x1c0 sound/core/pcm_native.c:1525 snd_pcm_action_single sound/core/pcm_native.c:1305 [inline] snd_pcm_action+0xe4/0x240 sound/core/pcm_native.c:1388 __snd_pcm_xrun+0x27f/0x7c0 sound/core/pcm_lib.c:180 snd_pcm_update_state+0x342/0x430 sound/core/pcm_lib.c:224 snd_pcm_update_hw_ptr0+0x10b2/0x1b00 sound/core/pcm_lib.c:493 snd_pcm_update_hw_ptr sound/core/pcm_lib.c:499 [inline] __snd_pcm_lib_xfer+0x510/0x1ce0 sound/core/pcm_lib.c:2326 snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241 snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630 snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline] snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline] snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2795 vfs_write+0x287/0xb40 fs/read_write.c:684 ksys_write+0x14b/0x260 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 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(&group->lock#2); lock((softirq_ctrl.lock)); lock(&group->lock#2); lock((softirq_ctrl.lock)); *** DEADLOCK *** 2 locks held by syz.0.46/6843: #0: ffff88814ccb7150 (&group->lock#2){+.+.}-{3:3}, at: __snd_pcm_lib_xfer+0x386/0x1ce0 sound/core/pcm_lib.c:2319 #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline] #1: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1bb/0x2c0 kernel/locking/spinlock_rt.c:57 stack backtrace: CPU: 0 UID: 0 PID: 6843 Comm: syz.0.46 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_circular_bug+0x2ee/0x310 kernel/locking/lockdep.c:2043 check_noncircular+0x134/0x160 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+0xb9b/0x2140 kernel/locking/lockdep.c:3908 __lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237 reacquire_held_locks+0x127/0x1d0 kernel/locking/lockdep.c:5385 __lock_release kernel/locking/lockdep.c:5574 [inline] lock_release+0x1b4/0x3e0 kernel/locking/lockdep.c:5889 __local_bh_enable_ip+0x10c/0x270 kernel/softirq.c:228 hrtimer_cancel+0x39/0x60 kernel/time/hrtimer.c:1491 dummy_hrtimer_stop+0xcf/0x100 sound/drivers/dummy.c:410 snd_pcm_do_stop+0x12a/0x1c0 sound/core/pcm_native.c:1525 snd_pcm_action_single sound/core/pcm_native.c:1305 [inline] snd_pcm_action+0xe4/0x240 sound/core/pcm_native.c:1388 __snd_pcm_xrun+0x27f/0x7c0 sound/core/pcm_lib.c:180 snd_pcm_update_state+0x342/0x430 sound/core/pcm_lib.c:224 snd_pcm_update_hw_ptr0+0x10b2/0x1b00 sound/core/pcm_lib.c:493 snd_pcm_update_hw_ptr sound/core/pcm_lib.c:499 [inline] __snd_pcm_lib_xfer+0x510/0x1ce0 sound/core/pcm_lib.c:2326 snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1241 snd_pcm_plug_write_transfer+0x2cb/0x4c0 sound/core/oss/pcm_plugin.c:630 snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1373 [inline] snd_pcm_oss_write1 sound/core/oss/pcm_oss.c:1439 [inline] snd_pcm_oss_write+0xba2/0x11a0 sound/core/oss/pcm_oss.c:2795 vfs_write+0x287/0xb40 fs/read_write.c:684 ksys_write+0x14b/0x260 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9528fcebe9 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:00007f952863e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f95291f5fa0 RCX: 00007f9528fcebe9 RDX: 000000000000fc36 RSI: 0000200000000500 RDI: 0000000000000003 RBP: 00007f9529051e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f95291f6038 R14: 00007f95291f5fa0 R15: 00007ffe192e0268 Tested on: commit: 11e7861d Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15d8d634580000 kernel config: https://syzkaller.appspot.com/x/.config?x=bd9738e00c1bbfb4 dashboard link: https://syzkaller.appspot.com/bug?extid=10b4363fb0f46527f3f3 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 patch: https://syzkaller.appspot.com/x/patch.diff?x=11b7fef0580000