INFO: task syz-executor.5:15218 blocked for more than 140 seconds.
Not tainted 4.19.126-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5 D29456 15218 22228 0x00000004
Call Trace:
context_switch kernel/sched/core.c:2826 [inline]
__schedule+0x8a2/0x1fc0 kernel/sched/core.c:3515
schedule+0x8d/0x1b0 kernel/sched/core.c:3559
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3617
__mutex_lock_common kernel/locking/mutex.c:1002 [inline]
__mutex_lock+0x5b8/0x1300 kernel/locking/mutex.c:1072
fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1457
chrdev_open+0x219/0x5c0 fs/char_dev.c:423
do_dentry_open+0x4a8/0x1160 fs/open.c:796
do_last fs/namei.c:3421 [inline]
path_openat+0xe06/0x2eb0 fs/namei.c:3537
do_filp_open+0x1a1/0x280 fs/namei.c:3567
do_sys_open+0x3aa/0x510 fs/open.c:1085
do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ca69
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fdf17c53c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00000000004f7680 RCX: 000000000045ca69
RDX: 0000000000000000 RSI: 0000000020000040 RDI: ffffffffffffff9c
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000007a0 R14: 00000000004ca784 R15: 00007fdf17c546d4
Showing all locks held in the system:
4 locks held by kworker/u4:1/23:
1 lock held by khungtaskd/1074:
#0: 00000000b7fe83fc (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/6136:
#0: 000000006ff402e8 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767
3 locks held by syz-executor.5/15176:
1 lock held by syz-executor.5/15218:
#0: 000000009147154c (&fb_info->lock){+.+.}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1457
=============================================
NMI backtrace for cpu 1
CPU: 1 PID: 1074 Comm: khungtaskd Not tainted 4.19.126-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
watchdog+0x962/0xe40 kernel/hung_task.c:287
kthread+0x30b/0x410 kernel/kthread.c:246
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.126-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_connect_worker
RIP: 0010:arch_local_save_flags arch/x86/include/asm/paravirt.h:784 [inline]
RIP: 0010:lockdep_hardirqs_off+0xfd/0x2c0 kernel/locking/lockdep.c:2901
Code: 55 b2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 9e 01 00 00 48 83 3d 4a 42 62 07 00 0f 84 8e 01 00 00 9c <58> 0f 1f 44 00 00 f6 c4 02 0f 85 dc 00 00 00 48 8d bb 50 08 00 00
RSP: 0018:ffff8880a9497990 EFLAGS: 00000082
RAX: 1ffffffff1164ab0 RBX: ffff8880a948a600 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880a948ae84
RBP: ffffffff813e08c9 R08: ffff8880a948a600 R09: ffffed101362bc7d
R10: ffffed101362bc7c R11: ffff88809b15e3e3 R12: ffff8880a948a600
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00f007d40 CR3: 0000000054375000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace: