syzbot


BUG: soft lockup in _do_fork

Status: auto-obsoleted due to no activity on 2022/09/05 14:27
Reported-by: syzbot+b75f3dafd896e91443af@syzkaller.appspotmail.com
First crash: 655d, last: 655d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: rcu detected stall in _do_fork syz error 3 775d 785d 0/1 upstream: reported syz repro on 2021/12/30 08:01
linux-4.19 BUG: soft lockup in _do_fork 1 1044d 1044d 0/1 auto-closed as invalid on 2021/08/12 22:53

Sample crash report:
watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [syz-executor.3:9532]
Modules linked in:
irq event stamp: 3943956
hardirqs last  enabled at (3943955): [<ffffffff87400976>] restore_regs_and_return_to_kernel+0x0/0x2a
hardirqs last disabled at (3943956): [<ffffffff874018ae>] apic_timer_interrupt+0x8e/0xa0 arch/x86/entry/entry_64.S:793
softirqs last  enabled at (223412): [<ffffffff8760068b>] __do_softirq+0x68b/0x9ff kernel/softirq.c:314
softirqs last disabled at (217841): [<ffffffff81321cf3>] invoke_softirq kernel/softirq.c:368 [inline]
softirqs last disabled at (217841): [<ffffffff81321cf3>] irq_exit+0x193/0x240 kernel/softirq.c:409
CPU: 0 PID: 9532 Comm: syz-executor.3 Not tainted 4.14.277-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809d32a200 task.stack: ffff88809e960000
RIP: 0010:pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:411 [inline]
RIP: 0010:__pv_queued_spin_lock_slowpath+0x265/0x910 kernel/locking/qspinlock.c:465
RSP: 0018:ffff88809e967af8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000003 RBX: ffff8880ba434f00 RCX: fffffbfff11c24dd
RDX: 00000000000011a4 RSI: 0000000000000000 RDI: 0000000000000286
RBP: ffffffff88e126e8 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: dffffc0000000000 R14: ffffffff88e126e9 R15: ffffed10174869e8
FS:  00007f57941a1700(0000) GS:ffff8880ba400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c000698000 CR3: 00000000990ac000 CR4: 00000000003406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:669 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:52 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:90 [inline]
 do_raw_spin_lock+0x178/0x200 kernel/locking/spinlock_debug.c:113
 spin_lock include/linux/spinlock.h:317 [inline]
 write_seqlock include/linux/seqlock.h:456 [inline]
 lock_mount_hash fs/mount.h:122 [inline]
 mntput_no_expire+0x18f/0x910 fs/namespace.c:1221
 mntput+0x5c/0x80 fs/namespace.c:1272
 free_fs_struct fs/fs_struct.c:89 [inline]
 exit_fs+0xdd/0x160 fs/fs_struct.c:107
 copy_process.part.0+0x42c1/0x71c0 kernel/fork.c:2005
 copy_process kernel/fork.c:1606 [inline]
 _do_fork+0x184/0xc80 kernel/fork.c:2092
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7f579582c0e9
RSP: 002b:00007f57941a1118 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007f579593ef60 RCX: 00007f579582c0e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000072a66000
RBP: 00007f579588608d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ffd764b2a3f R14: 00007f57941a1300 R15: 0000000000022000
Code: 84 c0 0f 85 2e 04 00 00 48 89 e9 48 89 ee c6 45 01 01 ba 00 80 00 00 48 c1 e9 03 83 e6 07 41 b8 01 00 00 00 4c 01 e9 eb 0b f3 90 <83> ea 01 0f 84 42 04 00 00 0f b6 01 40 38 f0 7f 08 84 c0 0f 85 
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 9550 Comm: syz-executor.1 Not tainted 4.14.277-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88809963c000 task.stack: ffff888092e90000
RIP: 0010:__default_send_IPI_shortcut+0x5f/0xa0 arch/x86/kernel/apic/ipi.c:46
RSP: 0018:ffff8880ba506fe8 EFLAGS: 00000002
RAX: 00000000000400f6 RBX: 0000000000040000 RCX: 0000000000000000
RDX: 0000000000040400 RSI: 00000000000000f6 RDI: 0000000000040000
RBP: ffffffff88cca000 R08: ffff88809c228000 R09: 1ffff11013845080
R10: ffff88809c22ce2f R11: ffff88809963c000 R12: ffff888098036cf8
R13: ffffed10135f78db R14: ffff88809afbc5f0 R15: dffffc0000000000
FS:  00007efdb94b5700(0000) GS:ffff8880ba500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007efdb94949d0 CR3: 0000000098e96000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 arch_irq_work_raise+0xc4/0x150 arch/x86/kernel/irq_work.c:31
 irq_work_queue kernel/irq_work.c:100 [inline]
 irq_work_queue+0x197/0x1e0 kernel/irq_work.c:87
 perf_output_wakeup kernel/events/ring_buffer.c:26 [inline]
 perf_output_put_handle+0x270/0x410 kernel/events/ring_buffer.c:125
 perf_output_end+0x11/0x90 kernel/events/ring_buffer.c:293
 __perf_event_output kernel/events/core.c:6289 [inline]
 perf_event_output_forward+0x100/0x1f0 kernel/events/core.c:6300
 __perf_event_overflow+0x113/0x310 kernel/events/core.c:7549
 perf_swevent_hrtimer+0x220/0x350 kernel/events/core.c:8757
 __run_hrtimer kernel/time/hrtimer.c:1223 [inline]
 __hrtimer_run_queues+0x30b/0xc80 kernel/time/hrtimer.c:1287
 hrtimer_interrupt+0x1e6/0x5e0 kernel/time/hrtimer.c:1321
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1079 [inline]
 smp_apic_timer_interrupt+0x117/0x5e0 arch/x86/kernel/apic/apic.c:1104
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
RIP: 0010:memset_erms+0xb/0x10 arch/x86/lib/memset_64.S:67
RSP: 0018:ffff8880ba507678 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff10
RAX: ffffed10174a0e00 RBX: ffff8880ba507798 RCX: 0000000000000000
RDX: 0000000000000058 RSI: 0000000000000000 RDI: ffff8880ba507780
RBP: 1ffff110174a0ed4 R08: 0000000000000001 R09: ffff8880ba507728
R10: ffff8880ba50777f R11: 0000000000000000 R12: ffff88809963c000
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880ba507728
 memset include/linux/string.h:361 [inline]
 __unwind_start+0x66/0x930 arch/x86/kernel/unwind_orc.c:511
 unwind_start arch/x86/include/asm/unwind.h:60 [inline]
 __save_stack_trace+0x63/0x160 arch/x86/kernel/stacktrace.c:43
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc mm/slab.c:3390 [inline]
 kmem_cache_alloc+0x111/0x3c0 mm/slab.c:3550
 dst_alloc+0xed/0x6d0 net/core/dst.c:107
 __ip6_dst_alloc net/ipv6/route.c:357 [inline]
 ip6_dst_alloc+0x39/0x2d0 net/ipv6/route.c:370
 icmp6_dst_alloc+0x155/0x580 net/ipv6/route.c:1768
 ndisc_send_skb+0xace/0x1390 net/ipv6/ndisc.c:463
 ndisc_send_rs+0x125/0x630 net/ipv6/ndisc.c:677
 addrconf_rs_timer+0x2bb/0x5a0 net/ipv6/addrconf.c:3769
 call_timer_fn+0x14a/0x650 kernel/time/timer.c:1280
 expire_timers+0x232/0x4d0 kernel/time/timer.c:1319
 __run_timers kernel/time/timer.c:1637 [inline]
 run_timer_softirq+0x1d5/0x5a0 kernel/time/timer.c:1650
 __do_softirq+0x24d/0x9ff kernel/softirq.c:288
 invoke_softirq kernel/softirq.c:368 [inline]
 irq_exit+0x193/0x240 kernel/softirq.c:409
 exiting_irq arch/x86/include/asm/apic.h:638 [inline]
 smp_apic_timer_interrupt+0x141/0x5e0 arch/x86/kernel/apic/apic.c:1106
 apic_timer_interrupt+0x93/0xa0 arch/x86/entry/entry_64.S:793
 </IRQ>
RIP: 0010:disconnect_mount fs/namespace.c:1478 [inline]
RIP: 0010:umount_tree+0x65f/0xb60 fs/namespace.c:1535
RSP: 0018:ffff888092e97a90 EFLAGS: 00000a02 ORIG_RAX: ffffffffffffff10
RAX: 0000000000000000 RBX: ffff88808d51ac88 RCX: ffffc90008c90000
RDX: 0000000000040000 RSI: ffffffff818dac2f RDI: ffff888099aee430
RBP: dffffc0000000000 R08: ffff88808d51aad0 R09: 0000000000000003
R10: 0000000000000000 R11: ffff88809963c000 R12: ffff888099aee400
R13: ffff888092e97ad8 R14: ffff88808d51ac00 R15: ffff88808d51ac10
 drop_collected_mounts+0x96/0x160 fs/namespace.c:1886
 put_mnt_ns fs/namespace.c:3345 [inline]
 put_mnt_ns+0x42/0x60 fs/namespace.c:3341
 create_new_namespaces+0x42f/0x720 kernel/nsproxy.c:128
 copy_namespaces+0x27b/0x310 kernel/nsproxy.c:165
 copy_process.part.0+0x25f8/0x71c0 kernel/fork.c:1794
 copy_process kernel/fork.c:1606 [inline]
 _do_fork+0x184/0xc80 kernel/fork.c:2092
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x7efdbab400e9
RSP: 002b:00007efdb94b5118 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007efdbac52f60 RCX: 00007efdbab400e9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000072a66000
RBP: 00007efdbab9a08d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ffeb732c22f R14: 00007efdb94b5300 R15: 0000000000022000
Code: 00 84 c0 74 04 3c 03 7e 45 8b 04 25 00 c3 5f ff f6 c4 10 75 e6 09 da 89 f0 09 d0 80 ce 04 83 fe 02 0f 44 c2 89 04 25 00 c3 5f ff <48> 83 c4 08 5b 5d c3 48 c7 c7 00 c3 5f ff 89 54 24 04 89 34 24 
----------------
Code disassembly (best guess):
   0:	84 c0                	test   %al,%al
   2:	0f 85 2e 04 00 00    	jne    0x436
   8:	48 89 e9             	mov    %rbp,%rcx
   b:	48 89 ee             	mov    %rbp,%rsi
   e:	c6 45 01 01          	movb   $0x1,0x1(%rbp)
  12:	ba 00 80 00 00       	mov    $0x8000,%edx
  17:	48 c1 e9 03          	shr    $0x3,%rcx
  1b:	83 e6 07             	and    $0x7,%esi
  1e:	41 b8 01 00 00 00    	mov    $0x1,%r8d
  24:	4c 01 e9             	add    %r13,%rcx
  27:	eb 0b                	jmp    0x34
  29:	f3 90                	pause
* 2b:	83 ea 01             	sub    $0x1,%edx <-- trapping instruction
  2e:	0f 84 42 04 00 00    	je     0x476
  34:	0f b6 01             	movzbl (%rcx),%eax
  37:	40 38 f0             	cmp    %sil,%al
  3a:	7f 08                	jg     0x44
  3c:	84 c0                	test   %al,%al
  3e:	0f                   	.byte 0xf
  3f:	85                   	.byte 0x85

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/05/08 14:27 linux-4.14.y e3a56aaade89 e60b1103 .config console log report info ci2-linux-4-14 BUG: soft lockup in _do_fork
* Struck through repros no longer work on HEAD.