INFO: task syz-executor.3:24174 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28072 24174 9733 0x00000004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1447 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x416011 Code: 49 89 fc 48 83 e7 0f 48 81 cf f0 00 00 00 49 8d 43 04 4c 39 d0 0f 83 ec 00 00 00 41 88 38 90 49 c1 ec 04 48 39 d6 74 5d 49 83 08 73 48 0f b6 02 48 89 cf 4c 89 c9 48 d3 e0 49 09 c4 90 48 8d RSP: 002b:0000000000c7fbf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000416011 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: 00000000188dcc0b R09: 00000000188dcc0f R10: 0000000000c7fcd0 R11: 0000000000000293 R12: 000000000076c920 R13: 000000000076c920 R14: 00000000000bcb4d R15: 000000000076bfcc INFO: task syz-executor.4:24189 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D26968 24189 9738 0x00004004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007f0195482c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f01954836d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000799 R14: 00000000004ca0ce R15: 000000000076bf2c INFO: task syz-executor.0:24193 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26872 24193 9719 0x00004004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007ff7a8905c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007ff7a89066d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000799 R14: 00000000004ca0ce R15: 000000000076bf2c INFO: task syz-executor.2:24196 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27592 24196 9726 0x00000004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x176/0x2c0 kernel/locking/semaphore.c:237 down+0x64/0x90 kernel/locking/semaphore.c:61 console_lock+0x29/0x80 kernel/printk/printk.c:2289 vcs_open+0x67/0xd0 drivers/tty/vt/vc_screen.c:688 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007f8e913a4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8e913a56d4 RCX: 000000000045c479 RDX: 0000000000020140 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000007ff R14: 00000000004ca7a7 R15: 000000000076bf2c INFO: task syz-executor.2:24197 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D27296 24197 9726 0x00000004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x176/0x2c0 kernel/locking/semaphore.c:237 down+0x64/0x90 kernel/locking/semaphore.c:61 console_lock+0x29/0x80 kernel/printk/printk.c:2289 vcs_open+0x67/0xd0 drivers/tty/vt/vc_screen.c:688 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007f8e91383c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8e913846d4 RCX: 000000000045c479 RDX: 0000000000020140 RSI: 0000000020000000 RDI: ffffffffffffff9c RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000007ff R14: 00000000004ca7a7 R15: 000000000076bfcc INFO: task syz-executor.5:24202 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D26872 24202 9740 0x00004004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007fcf035dcc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fcf035dd6d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000799 R14: 00000000004ca0ce R15: 000000000076bf2c INFO: task syz-executor.5:24203 blocked for more than 143 seconds. Not tainted 5.6.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28360 24203 9740 0x00000004 Call Trace: context_switch kernel/sched/core.c:3380 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4080 schedule+0xdc/0x2b0 kernel/sched/core.c:4154 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4213 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3490 [inline] path_openat+0x12ee/0x3490 fs/namei.c:3607 do_filp_open+0x192/0x260 fs/namei.c:3637 do_sys_openat2+0x5eb/0x7e0 fs/open.c:1149 do_sys_open+0xf2/0x180 fs/open.c:1165 __do_sys_openat fs/open.c:1179 [inline] __se_sys_openat fs/open.c:1174 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1174 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c479 Code: 15 08 c5 01 48 89 04 24 48 8d 44 24 28 48 89 44 24 08 e8 ea 87 fa ff 48 8d 7c 24 78 0f 57 c0 48 8d 7f d0 48 89 6c 24 f0 48 8d <6c> 24 f0 e8 d4 33 00 00 48 8b 6d 00 48 c7 44 24 38 00 00 00 00 66 RSP: 002b:00007fcf035bbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fcf035bc6d4 RCX: 000000000045c479 RDX: 0000000000000000 RSI: 00000000200000c0 RDI: ffffffffffffff9c RBP: 000000000076bfc0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000799 R14: 00000000004ca0ce R15: 000000000076bfcc Showing all locks held in the system: 3 locks held by kworker/u4:0/7: 5 locks held by kworker/u4:6/309: 1 lock held by khungtaskd/420: #0: ffffffff89bac340 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 4 locks held by rs:main Q:Reg/9582: 1 lock held by rsyslogd/9584: #0: ffff8880992b78e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821 2 locks held by getty/9674: #0: ffff8880a6c85090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005a9b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9675: #0: ffff8880a1752090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005b2b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9676: #0: ffff8880a878f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005afb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9677: #0: ffff88808b704090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005a8b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9678: #0: ffff88809db9c090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005b1b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9679: #0: ffff8880a3439090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005b0b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9680: #0: ffff888098558090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90005a4b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/24174: #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1447 2 locks held by syz-executor.1/24185: 1 lock held by syz-executor.4/24189: #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.0/24193: #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.5/24202: #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.5/24203: #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3ee6070 (&fb_info->lock){+.+.}, at: fb_open+0xd7/0x450 drivers/video/fbdev/core/fbmem.c:1418 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 420 Comm: khungtaskd Not tainted 5.6.0-rc3-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.6.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:__rcu_read_unlock+0x0/0x700 kernel/rcu/tree_plugin.h:391 Code: c7 c7 90 b5 a5 8a e8 1f 67 51 00 e9 49 e8 ff ff 48 c7 c7 00 90 a0 89 e8 2e 67 51 00 e9 01 e8 ff ff 66 0f 1f 84 00 00 00 00 00 <48> b8 00 00 00 00 00 fc ff df 55 48 89 e5 41 57 65 4c 8b 3c 25 c0 RSP: 0018:ffffc90000cdfcc8 EFLAGS: 00000206 RAX: ffff8880a99aa1c0 RBX: ffff888097bd3600 RCX: ffffffff87d17c7c RDX: 0000000000000000 RSI: ffffffff87d179ef RDI: 0000000000000001 RBP: ffffc90000cdfd20 R08: ffff8880a99aa1c0 R09: ffffed1015d0707c R10: ffffed1015d0707b R11: ffff8880ae8383db R12: 0000000000000001 R13: 00000000000003ff R14: 0000000000000001 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000002079d7000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264 worker_thread+0x98/0xe40 kernel/workqueue.c:2410 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352