Hello,
syzkaller hit the following crash on
ad4dac17f9d563b9e34aab78a34293b10993e9b5
git://
git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/master
compiler: gcc (GCC) 7.1.1 20170620
.config is attached
Raw console output is attached.
Unfortunately, I don't have any reproducer for this bug yet.
INFO: task syz-executor3:12157 blocked for more than 120 seconds.
Not tainted 4.15.0-rc2-next-20171208+ #63
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor3 D25536 12157 3362 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2800 [inline]
__schedule+0x8eb/0x2060 kernel/sched/core.c:3376
schedule+0xf5/0x430 kernel/sched/core.c:3435
schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3493
__mutex_lock_common kernel/locking/mutex.c:833 [inline]
__mutex_lock+0xaad/0x1a80 kernel/locking/mutex.c:893
mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
__blkdev_driver_ioctl block/ioctl.c:303 [inline]
blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601
block_ioctl+0xea/0x130 fs/block_dev.c:1860
vfs_ioctl fs/ioctl.c:46 [inline]
do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:686
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a39
RSP: 002b:00007fd85b57ec58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000758190 RCX: 0000000000452a39
RDX: 0000000020e67fd8 RSI: 00000000400454ca RDI: 0000000000000016
RBP: 000000000000005b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006ee928
R13: 00000000ffffffff R14: 00007fd85b57f6d4 R15: 0000000000000002
Showing all locks held in the system:
2 locks held by khungtaskd/671:
#0: (rcu_read_lock){....}, at: [<0000000053bc3983>]
check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
#0: (rcu_read_lock){....}, at: [<0000000053bc3983>] watchdog+0x1c5/0xd60
kernel/hung_task.c:249
#1: (tasklist_lock){.+.+}, at: [<00000000c2c6381b>]
debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4554
2 locks held by getty/3115:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3116:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3117:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3118:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3119:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
2 locks held by getty/3120:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
1 lock held by syz-executor3/12157:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d5130113>]
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
1 lock held by syz-executor7/12154:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d5130113>]
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
1 lock held by syz-executor7/12168:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d5130113>]
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
1 lock held by syz-executor5/12216:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d5130113>]
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
2 locks held by getty/12231:
#0: (&tty->ldisc_sem){++++}, at: [<00000000e7f92d1f>]
ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
#1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000f15a7c4f>]
n_tty_read+0x2f2/0x1a10 drivers/tty/n_tty.c:2131
1 lock held by blkid/12232:
#0: (&lo->lo_ctl_mutex/1){+.+.}, at: [<00000000d5130113>]
lo_ioctl+0x8b/0x1b90 drivers/block/loop.c:1355
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 671 Comm: khungtaskd Not tainted 4.15.0-rc2-next-20171208+ #63
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x194/0x257 lib/dump_stack.c:53
nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
check_hung_task kernel/hung_task.c:132 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
watchdog+0x90c/0xd60 kernel/hung_task.c:249
kthread+0x37a/0x440 kernel/kthread.c:238
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:524
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.15.0-rc2-next-20171208+ #63
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:unwind_next_frame.part.6+0x5f1/0xb40 include/linux/compiler.h:183
RSP: 0018:ffff8801db306e28 EFLAGS: 00000806
RAX: dffffc0000000000 RBX: ffff8801db306f48 RCX: ffff8801db306ef8
RDX: ffff8801db306f70 RSI: 1ffff1003b660dcf RDI: ffff8801d9f97f48
RBP: ffff8801db306f20 R08: ffff8801db306f80 R09: ffff8801d9f88300
R10: 000000000000000b R11: ffffed003b660df3 R12: 1ffff1003b660dcb
R13: ffff8801db307490 R14: 1ffff1003b660dcf R15: ffff8801db306f98
FS: 0000000000000000(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000001e5e000 CR3: 00000001cb1b5000 CR4: 00000000001406e0
DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
<IRQ>
unwind_next_frame+0x3e/0x50 arch/x86/kernel/unwind_frame.c:287
__save_stack_trace+0x6e/0xd0 arch/x86/kernel/stacktrace.c:44
save_stack_trace+0x1a/0x20 arch/x86/kernel/stacktrace.c:60
add_xhlock kernel/locking/lockdep.c:4880 [inline]
check_add_xhlock kernel/locking/lockdep.c:4907 [inline]
lock_acquire_crosslock kernel/locking/lockdep.c:4979 [inline]
__lock_acquire+0x324e/0x47f0 kernel/locking/lockdep.c:3503
lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4004
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:159
rq_lock_irqsave kernel/sched/sched.h:1750 [inline]
update_blocked_averages+0x124/0x1b60 kernel/sched/fair.c:7353
rebalance_domains+0x145/0xcc0 kernel/sched/fair.c:9122
run_rebalance_domains+0x381/0x780 kernel/sched/fair.c:9383
__do_softirq+0x29d/0xbb2 kernel/softirq.c:285
invoke_softirq kernel/softirq.c:365 [inline]
irq_exit+0x1d3/0x210 kernel/softirq.c:405
scheduler_ipi+0x32a/0x830 kernel/sched/core.c:1804
smp_reschedule_interrupt+0xe6/0x670 arch/x86/kernel/smp.c:277
reschedule_interrupt+0xa9/0xb0 arch/x86/entry/entry_64.S:944
</IRQ>
RIP: 0010:native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54
RSP: 0018:ffff8801d9f97da8 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02
RAX: dffffc0000000000 RBX: 1ffff1003b3f2fb8 RCX: 0000000000000000
RDX: 1ffffffff0c5975c RSI: 0000000000000001 RDI: ffffffff862cbae0
RBP: ffff8801d9f97da8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: ffff8801d9f97e60 R14: ffffffff869efaa0 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:93 [inline]
default_idle+0xbf/0x430 arch/x86/kernel/process.c:355
arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:346
default_idle_call+0x36/0x90 kernel/sched/idle.c:98
cpuidle_idle_call kernel/sched/idle.c:156 [inline]
do_idle+0x24a/0x3b0 kernel/sched/idle.c:246
cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:351
start_secondary+0x330/0x460 arch/x86/kernel/smpboot.c:277
secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:237
Code: 8b 6d 00 4c 89 f6 48 c1 ee 03 80 3c 06 00 0f 85 e9 04 00 00 49 c1 ee
03 48 b8 00 00 00 00 00 fc ff df 4c 89 69 80 41 c6 04 06 f8 <e9> 97 fb ff
ff 80 3d f7 60 6e 05 00 0f 85 fc fc ff ff 49 8d be
---
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