syzbot


BUG: soft lockup in snd_virmidi_output_trigger

Status: fixed on 2018/08/28 17:48
Reported-by: syzbot+619d9f40141d826b097e@syzkaller.appspotmail.com
Fix commit: 50e9ffb1996a ALSA: virmidi: Fix too long output trigger loop
First crash: 1634d, last: 1532d

Sample crash report:
watchdog: BUG: soft lockup - CPU#1 stuck for 23s! [syz-executor2:26299]
Modules linked in:
irq event stamp: 6690
hardirqs last  enabled at (6689): [<ffffffff876ef7f4>] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline]
hardirqs last  enabled at (6689): [<ffffffff876ef7f4>] _raw_spin_unlock_irqrestore+0x74/0xc0 kernel/locking/spinlock.c:184
hardirqs last disabled at (6690): [<ffffffff87800905>] interrupt_entry+0xb5/0xf0 arch/x86/entry/entry_64.S:625
softirqs last  enabled at (138): [<ffffffff87a00778>] __do_softirq+0x778/0xaf5 kernel/softirq.c:311
softirqs last disabled at (127): [<ffffffff81475281>] invoke_softirq kernel/softirq.c:365 [inline]
softirqs last disabled at (127): [<ffffffff81475281>] irq_exit+0x1d1/0x200 kernel/softirq.c:405
CPU: 1 PID: 26299 Comm: syz-executor2 Not tainted 4.17.0-rc5+ #57
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:ffff88018d4ff7a0 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: dffffc0000000000 RBX: 0000000000000286 RCX: 0000000000000000
RDX: 1ffffffff11a30e5 RSI: 0000000000000001 RDI: 0000000000000286
RBP: ffff88018d4ff7b0 R08: ffffed00391dad62 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801c8ed6b08
R13: ffff88018d4ff830 R14: 0000000000000001 R15: ffff8801d907ed80
FS:  00007ff499e00700(0000) GS:ffff8801daf00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff499dffdb8 CR3: 00000001c92ed000 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+0x4d0/0x6b0 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/0x960 fs/read_write.c:485
 vfs_write+0x1f8/0x560 fs/read_write.c:549
 ksys_write+0xf9/0x250 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455a09
RSP: 002b:00007ff499dffc68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff499e006d4 RCX: 0000000000455a09
RDX: 0000000020000338 RSI: 0000000020000280 RDI: 0000000000000018
RBP: 000000000072c000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000077b R14: 00000000006ff428 R15: 0000000000000002
Code: c7 28 87 d1 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 0e 8f 62 01 00 74 0e 48 89 df 57 9d <0f> 1f 44 00 00 eb bb 0f 0b 0f 0b e8 1f a2 46 fa eb 97 e8 18 a2 
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 26275 Comm: syz-executor2 Not tainted 4.17.0-rc5+ #57
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:send_midi_event sound/core/seq/oss/seq_oss_midi.c:621 [inline]
RIP: 0010:snd_seq_oss_midi_input+0x7e4/0xfe0 sound/core/seq/oss/seq_oss_midi.c:537
RSP: 0018:ffff8801ca017400 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: 0000000000000002 RCX: ffffc900028a7000
RDX: 1ffff10039195487 RSI: 0000000000000004 RDI: 0000000000000005
RBP: ffff8801ca017508 R08: ffff8801cf41c140 R09: ffffed0039402e90
R10: ffffed0039402e90 R11: ffff8801ca017481 R12: ffff8801c8caa000
R13: ffff8801ce095600 R14: 1ffff10039402e84 R15: ffff8801c8caa438
FS:  00007ff499e42700(0000) GS:ffff8801dae00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 00000001c92ed000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 snd_seq_oss_event_input+0x197/0x250 sound/core/seq/oss/seq_oss_event.c:442
 snd_seq_deliver_single_event.constprop.15+0x89a/0xa20 sound/core/seq/seq_clientmgr.c:622
 deliver_to_subscribers sound/core/seq/seq_clientmgr.c:677 [inline]
 snd_seq_deliver_event+0x35e/0x950 sound/core/seq/seq_clientmgr.c:812
 snd_seq_kernel_client_dispatch+0x157/0x1a0 sound/core/seq/seq_clientmgr.c:2330
 snd_virmidi_output_trigger+0x444/0x6b0 sound/core/seq/seq_virmidi.c:198
 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/0x960 fs/read_write.c:485
 vfs_write+0x1f8/0x560 fs/read_write.c:549
 ksys_write+0xf9/0x250 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455a09
RSP: 002b:00007ff499e41c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff499e426d4 RCX: 0000000000455a09
RDX: 0000000020000338 RSI: 0000000020000280 RDI: 0000000000000014
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000077b R14: 00000000006ff428 R15: 0000000000000000
Code: 84 d2 74 08 4c 89 ef e8 6b e0 ea fb 4c 89 fa 41 8b 75 00 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 ac 06 00 00 <49> 8b bc 24 38 04 00 00 48 8b 95 10 ff ff ff 89 d9 e8 96 17 00 

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2018/05/19 05:24 upstream 2c71d338bef2 849705db .config log report
ci-upstream-kasan-gce-root 2018/04/08 20:03 upstream 3fd14cdcc05a 77bd5117 .config log report
ci-upstream-kasan-gce-386 2018/07/19 20:04 upstream 024ddc0ce104 49f35839 .config log report
* Struck through repros no longer work on HEAD.