bisecting fixing commit since 3e732ebf7316ac83e8562db7e64cc68aec390a18
building syzkaller on 975824663d2c65cf7a4d7829fa95f118b675c3be
testing commit 3e732ebf7316ac83e8562db7e64cc68aec390a18
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: 7cb610257b082efdd6690d6642d0e1770d86c5d5f2698b9148a7b24ad590201b
all runs: crashed: INFO: task hung in nbd_add_socket
testing current HEAD 9be9ed2612b5aedb52a2c240edb1630b6b743cb6
testing commit 9be9ed2612b5aedb52a2c240edb1630b6b743cb6
compiler: gcc (GCC) 10.2.1 20210217, GNU ld (GNU Binutils for Debian) 2.35.2
kernel signature: cc4902dc0643471a8cde5f391f3957dc418e51691e6bb575a91202f9837c6785
all runs: crashed: INFO: task hung in nbd_add_socket
revisions tested: 2, total time: 23m41.960105754s (build: 11m43.955638557s, test: 11m34.212763656s)
the crash still happens on HEAD
commit msg: Merge tag 'platform-drivers-x86-v5.18-4' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
crash: INFO: task hung in nbd_add_socket
INFO: task syz-executor.0:4099 blocked for more than 143 seconds.
Not tainted 5.18.0-rc6-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:28448 pid: 4099 ppid: 4061 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:5073 [inline]
__schedule+0xa5a/0x4c70 kernel/sched/core.c:6388
schedule+0xd2/0x1f0 kernel/sched/core.c:6460
blk_mq_freeze_queue_wait+0xec/0x120 block/blk-mq.c:179
nbd_add_socket+0x152/0x7e0 drivers/block/nbd.c:1109
__nbd_ioctl drivers/block/nbd.c:1454 [inline]
nbd_ioctl+0x3aa/0x8f0 drivers/block/nbd.c:1511
blkdev_ioctl+0x2ff/0x660 block/ioctl.c:588
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:870 [inline]
__se_sys_ioctl fs/ioctl.c:856 [inline]
__x64_sys_ioctl+0x11f/0x190 fs/ioctl.c:856
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7fe054089049
RSP: 002b:00007fe055298168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fe05419bf60 RCX: 00007fe054089049
RDX: 0000000000000005 RSI: 000000000000ab00 RDI: 0000000000000004
RBP: 00007fe0540e308d R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe548e494f R14: 00007fe055298300 R15: 0000000000022000
Showing all locks held in the system:
3 locks held by kworker/u4:0/8:
#0: ffff8880b9f39f18 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2b/0x120 kernel/sched/core.c:554
#1: ffff8880b9f27888 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x176/0x4e0 kernel/sched/psi.c:880
#2: ffff8880b9f28458 (&base->lock){-.-.}-{2:2}, at: lock_timer_base+0x49/0x1a0 kernel/time/timer.c:946
1 lock held by khungtaskd/28:
#0: ffffffff8ad773a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6467
2 locks held by getty/3270:
#0: ffff88814bf18098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x1f/0x70 drivers/tty/tty_ldisc.c:244
#1: ffffc900028e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x9d7/0xed0 drivers/tty/n_tty.c:2075
1 lock held by syz-executor.0/4099:
#0: ffff88814849e198 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x120/0x8f0 drivers/block/nbd.c:1504
=============================================
NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted 5.18.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106
nmi_cpu_backtrace.cold+0x30/0xc0 lib/nmi_backtrace.c:111
nmi_trigger_cpumask_backtrace+0x18f/0x1d0 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
watchdog+0x88c/0xbf0 kernel/hung_task.c:369
kthread+0x299/0x340 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 45 Comm: kworker/u4:2 Not tainted 5.18.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: 0x0 (phy6)
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:29 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:70 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:106 [inline]
RIP: 0010:lock_is_held_type+0x51/0x140 kernel/locking/lockdep.c:5680
Code: 77 77 85 c0 0f 85 ca 00 00 00 65 4c 8b 24 25 00 70 02 00 41 8b 94 24 5c 0a 00 00 85 d2 0f 85 b1 00 00 00 48 89 fd 41 89 f6 9c <8f> 04 24 fa 48 c7 c7 c0 8d eb 88 31 db e8 7d 0c 00 00 41 8b 84 24
RSP: 0018:ffffc90000b67b70 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffffffff8ad772e0
RBP: ffffffff8ad772e0 R08: 0000000000000000 R09: ffffffff8ca2db17
R10: fffffbfff1945b62 R11: 0000000000000001 R12: ffff888010a09d40
R13: 00000000ffffffff R14: 00000000ffffffff R15: ffff8880b9f3a938
FS: 0000000000000000(0000) GS:ffff8880b9f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33d8be2990 CR3: 000000000aa8e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
lock_is_held include/linux/lockdep.h:283 [inline]
rcu_read_lock_sched_held+0x3a/0x70 kernel/rcu/update.c:125
trace_lock_release include/trace/events/lock.h:58 [inline]
lock_release+0x522/0x720 kernel/locking/lockdep.c:5652
__raw_spin_unlock include/linux/spinlock_api_smp.h:141 [inline]
_raw_spin_unlock+0x12/0x40 kernel/locking/spinlock.c:186
raw_spin_rq_unlock_irq kernel/sched/sched.h:1308 [inline]
finish_lock_switch kernel/sched/core.c:4833 [inline]
finish_task_switch.isra.0+0x314/0xb40 kernel/sched/core.c:4951
context_switch kernel/sched/core.c:5076 [inline]
__schedule+0xa62/0x4c70 kernel/sched/core.c:6388
schedule+0xd2/0x1f0 kernel/sched/core.c:6460
worker_thread+0x150/0xec0 kernel/workqueue.c:2457
kthread+0x299/0x340 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
----------------
Code disassembly (best guess):
0: 77 77 ja 0x79
2: 85 c0 test %eax,%eax
4: 0f 85 ca 00 00 00 jne 0xd4
a: 65 4c 8b 24 25 00 70 mov %gs:0x27000,%r12
11: 02 00
13: 41 8b 94 24 5c 0a 00 mov 0xa5c(%r12),%edx
1a: 00
1b: 85 d2 test %edx,%edx
1d: 0f 85 b1 00 00 00 jne 0xd4
23: 48 89 fd mov %rdi,%rbp
26: 41 89 f6 mov %esi,%r14d
29: 9c pushfq
* 2a: 8f 04 24 popq (%rsp) <-- trapping instruction
2d: fa cli
2e: 48 c7 c7 c0 8d eb 88 mov $0xffffffff88eb8dc0,%rdi
35: 31 db xor %ebx,%ebx
37: e8 7d 0c 00 00 callq 0xcb9
3c: 41 rex.B
3d: 8b .byte 0x8b
3e: 84 .byte 0x84
3f: 24 .byte 0x24