On Mon, 09 Apr 2018 07:58:01 +0200, syzbot wrote: > > Hello, > > syzbot hit the following crash on upstream commit > 3fd14cdcc05a682b03743683ce3a726898b20555 (Fri Apr 6 19:15:41 2018 +0000) > Merge tag 'mtd/for-4.17' of git://git.infradead.org/linux-mtd > syzbot dashboard link: > https://syzkaller.appspot.com/bug?extid=619d9f40141d826b097e > > Unfortunately, I don't have any reproducer for this crash yet. > Raw console output: > https://syzkaller.appspot.com/x/log.txt?id=4594231414882304 > Kernel config: > https://syzkaller.appspot.com/x/.config?id=-5813481738265533882 > compiler: gcc (GCC) 8.0.1 20180301 (experimental) > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+619d9f40141d826b097e@xxxxxxxxxxxxxxxxxxxxxxxxx > It will help syzbot understand when the bug is fixed. See footer for > details. > If you forward the report, please keep this part and the footer. > > 8021q: adding VLAN 0 to HW filter on device team0 > IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready > 8021q: adding VLAN 0 to HW filter on device team0 > IPv6: ADDRCONF(NETDEV_UP): team0: link is not ready > 8021q: adding VLAN 0 to HW filter on device team0 > watchdog: BUG: soft lockup - CPU#1 stuck for 134s! [syz-executor2:10431] > Modules linked in: > irq event stamp: 35856 > hardirqs last enabled at (35855): [<ffffffff874a1734>] > __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 > [inline] > hardirqs last enabled at (35855): [<ffffffff874a1734>] > _raw_spin_unlock_irqrestore+0x74/0xc0 kernel/locking/spinlock.c:184 > hardirqs last disabled at (35856): [<ffffffff87600901>] > interrupt_entry+0xb1/0xf0 arch/x86/entry/entry_64.S:624 > softirqs last enabled at (162): [<ffffffff87800778>] > __do_softirq+0x778/0xaf5 kernel/softirq.c:311 > softirqs last disabled at (95): [<ffffffff81467a61>] invoke_softirq > kernel/softirq.c:365 [inline] > softirqs last disabled at (95): [<ffffffff81467a61>] > irq_exit+0x1d1/0x200 kernel/softirq.c:405 > CPU: 1 PID: 10431 Comm: syz-executor2 Not tainted 4.16.0+ #4 > Hardware name: Google Google Compute Engine/Google Compute Engine, > BIOS Google 01/01/2011 > RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:783 > [inline] > RIP: 0010:__raw_spin_unlock_irqrestore > include/linux/spinlock_api_smp.h:160 [inline] > RIP: 0010:_raw_spin_unlock_irqrestore+0xa1/0xc0 > kernel/locking/spinlock.c:184 > RSP: 0018:ffff880184db7780 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 > RAX: dffffc0000000000 RBX: 0000000000000282 RCX: 0000000000000000 > RDX: 1ffffffff1162e55 RSI: 0000000000000001 RDI: 0000000000000282 > RBP: ffff880184db7790 R08: ffffed0035d21962 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801ae90cb08 > R13: ffff880184db7810 R14: 0000000000000001 R15: ffff8801cb9a5880 > FS: 00007fc943ad8700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fc943ad7db8 CR3: 00000001b070d000 CR4: 00000000001406e0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > spin_unlock_irqrestore include/linux/spinlock.h:365 [inline] > snd_virmidi_output_trigger+0x522/0x6c0 sound/core/seq/seq_virmidi.c:205 > snd_rawmidi_output_trigger sound/core/rawmidi.c:150 [inline] > snd_rawmidi_kernel_write1+0x519/0x700 sound/core/rawmidi.c:1288 > snd_rawmidi_write+0x2e2/0xdc0 sound/core/rawmidi.c:1338 > __vfs_write+0x10b/0x880 fs/read_write.c:485 > vfs_write+0x1f8/0x560 fs/read_write.c:549 > ksys_write+0xf9/0x250 fs/read_write.c:598 > SYSC_write fs/read_write.c:610 [inline] > SyS_write+0x24/0x30 fs/read_write.c:607 > do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287 > entry_SYSCALL_64_after_hwframe+0x42/0xb7 > RIP: 0033:0x455259 > RSP: 002b:00007fc943ad7c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 00007fc943ad86d4 RCX: 0000000000455259 > RDX: 00000000e78e624c RSI: 0000000020000040 RDI: 0000000000000014 > RBP: 000000000072c010 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000000006ca R14: 00000000006fd390 R15: 0000000000000002 > Code: c7 a8 72 b1 88 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea > 03 80 3c 02 00 75 21 48 83 3d 4e 5b 67 01 00 74 0e 48 89 df 57 9d > <0f> 1f 44 00 00 eb bb 0f 0b 0f 0b e8 6f 29 68 fa eb 97 e8 68 29 This is quite new, and I still don't figure out what went wrong. At first I thought of the endless loop in snd_virmidi_output_trigger() (e.g the error handling of snd_midi_event_encode() continues the loop, and it may go into an endless loop in theory. But, practically, snd_midi_event_encode() never returns an error, so it shouldn't matter.) But it doesn't explain why the report points to spin_unlock_IRQ restore(). If you have a similar report or any relevant information, please let me know. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
