bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217 building syzkaller on fc7735a27949755327024847e12dcc1b868bcb99 testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.4.1 20210217 kernel signature: 818fc9426e1d15f6359eabe61a42638469136855adf223ea3e13f8e0789a3cd3 all runs: crashed: INFO: task hung in sync_inodes_sb testing current HEAD 1e986fe9ad15b8406034c504afc5ae76f0a8e852 testing commit 1e986fe9ad15b8406034c504afc5ae76f0a8e852 with gcc (GCC) 8.4.1 20210217 kernel signature: e4b20f621ff3de520c1c7d4d5a26bd935852e0842a0abe0e221e01bc235aa32c all runs: crashed: INFO: task hung in sync_inodes_sb revisions tested: 2, total time: 41m11.775514534s (build: 26m22.662218302s, test: 14m24.690974541s) the crash still happens on HEAD commit msg: Linux 4.19.191 crash: INFO: task hung in sync_inodes_sb Bluetooth: hci2: command 0x0406 tx timeout Bluetooth: hci4: command 0x0406 tx timeout Bluetooth: hci1: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci0: command 0x0406 tx timeout INFO: task syz-executor.2:5903 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D23576 5903 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007ffd2973f2c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007ffd2973f399 RSI: 0000000000000002 RDI: 00007ffd2973f390 RBP: 00007ffd2973f390 R08: 00000000ffffffff R09: 00007ffd2973f160 R10: 0000000002feb8e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007ffd29740440 R14: 0000000002feb810 R15: 0000000000000002 INFO: task syz-executor.0:5905 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D23512 5905 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007ffd4b50d878 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007ffd4b50d949 RSI: 0000000000000002 RDI: 00007ffd4b50d940 RBP: 00007ffd4b50d940 R08: 00000000ffffffff R09: 00007ffd4b50d710 R10: 000000000255d8e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007ffd4b50e9f0 R14: 000000000255d810 R15: 0000000000000002 INFO: task syz-executor.4:5906 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D23640 5906 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007fffcbda5118 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007fffcbda51e9 RSI: 0000000000000002 RDI: 00007fffcbda51e0 RBP: 00007fffcbda51e0 R08: 00000000ffffffff R09: 00007fffcbda4fb0 R10: 000000000238d8e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007fffcbda6290 R14: 000000000238d810 R15: 0000000000000002 INFO: task syz-executor.3:5908 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D23624 5908 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007fffbf61a4b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007fffbf61a589 RSI: 0000000000000002 RDI: 00007fffbf61a580 RBP: 00007fffbf61a580 R08: 00000000ffffffff R09: 00007fffbf61a350 R10: 0000000001c4b8e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007fffbf61b630 R14: 0000000001c4b810 R15: 0000000000000002 INFO: task syz-executor.5:5910 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D23864 5910 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007ffee9f9c9c8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007ffee9f9ca99 RSI: 0000000000000002 RDI: 00007ffee9f9ca90 RBP: 00007ffee9f9ca90 R08: 00000000ffffffff R09: 00007ffee9f9c860 R10: 0000000001d6b8e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007ffee9f9db40 R14: 0000000001d6b810 R15: 0000000000000002 INFO: task syz-executor.1:5911 blocked for more than 140 seconds. Not tainted 4.19.191-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D23336 5911 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x80c/0x1f70 kernel/sched/core.c:3517 schedule+0x7f/0x1b0 kernel/sched/core.c:3561 wb_wait_for_completion+0x14f/0x1c0 fs/fs-writeback.c:222 sync_inodes_sb+0x183/0x8e0 fs/fs-writeback.c:2479 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem fs/sync.c:67 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:48 generic_shutdown_super+0x69/0x330 fs/super.c:442 kill_block_super+0x96/0xe0 fs/super.c:1185 deactivate_locked_super+0x77/0xd0 fs/super.c:329 deactivate_super fs/super.c:360 [inline] deactivate_super+0x13f/0x160 fs/super.c:356 cleanup_mnt+0xa3/0x130 fs/namespace.c:1098 __cleanup_mnt+0xd/0x10 fs/namespace.c:1105 task_work_run+0x108/0x180 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:193 [inline] exit_to_usermode_loop+0x185/0x1e0 arch/x86/entry/common.c:167 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x413/0x4e0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x466ca7 Code: Bad RIP value. RSP: 002b:00007ffeca9c2498 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000466ca7 RDX: 00007ffeca9c2569 RSI: 0000000000000002 RDI: 00007ffeca9c2560 RBP: 00007ffeca9c2560 R08: 00000000ffffffff R09: 00007ffeca9c2330 R10: 00000000024718e3 R11: 0000000000000246 R12: 00000000004ae4c5 R13: 00007ffeca9c3610 R14: 0000000002471810 R15: 0000000000000002 Showing all locks held in the system: 2 locks held by kworker/u4:0/7: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 0000000073771d9f ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 2 locks held by kworker/u4:2/35: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 000000004d55e446 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 2 locks held by kworker/u4:3/454: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 000000002461414a ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 2 locks held by kworker/u4:4/602: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 000000006e01b817 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 1 lock held by khungtaskd/1100: #0: 000000002d623416 (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4443 1 lock held by in:imklog/5582: #0: 00000000695ce52e (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 2 locks held by syz-executor.2/5903: #0: 00000000db5567e4 (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 00000000db5567e4 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 00000000596a55fb (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000596a55fb (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by syz-executor.0/5905: #0: 000000006415cee5 (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 000000006415cee5 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 0000000087e2b331 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 0000000087e2b331 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by syz-executor.4/5906: #0: 0000000046375efa (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 0000000046375efa (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 0000000010e57d6c (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 0000000010e57d6c (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by syz-executor.3/5908: #0: 000000004644451f (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 000000004644451f (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 00000000599ad1bd (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000599ad1bd (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by syz-executor.5/5910: #0: 00000000725ab850 (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 00000000725ab850 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 000000006c060f2b (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 000000006c060f2b (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by syz-executor.1/5911: #0: 00000000d0567096 (&type->s_umount_key#50){+.+.}, at: deactivate_super fs/super.c:359 [inline] #0: 00000000d0567096 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:356 #1: 0000000086a4a44d (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 0000000086a4a44d (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2477 2 locks held by kworker/u4:5/7105: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 000000001ef2c721 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 2 locks held by kworker/u4:6/7265: #0: 00000000532328a9 ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2123 #1: 000000005ce1b335 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2127 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1100 Comm: khungtaskd Not tainted 4.19.191-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+0x17c/0x226 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x120 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:203 [inline] watchdog+0x5c3/0xb40 kernel/hung_task.c:287 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.191-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: phy10 ieee80211_iface_work RIP: 0010:rcu_is_watching+0xb/0x30 kernel/rcu/tree.c:1025 Code: 3f 00 eb e2 48 89 45 e8 e8 f2 42 3f 00 48 8b 45 e8 eb 94 66 66 2e 0f 1f 84 00 00 00 00 00 90 55 48 89 e5 65 ff 05 c5 93 b1 7e 40 ff ff ff 83 f0 01 65 ff 0d b6 93 b1 7e 74 02 5d c3 e8 af f6 RSP: 0018:ffff8881f4d1fd40 EFLAGS: 00000282 RAX: 0000000000000001 RBX: ffffffff88bda820 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff813d8dbb RDI: ffff8881f4d0ee84 RBP: ffff8881f4d1fd40 R08: 0000000000004ab1 R09: ffffffff89edce08 R10: ffff8881f4d0eeb0 R11: 0000000000000001 R12: ffff8881f4c98500 R13: ffff8881f6016940 R14: ffff8881d7016c00 R15: ffff8881cf636e80 FS: 0000000000000000(0000) GS:ffff8881f6700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efc1d6cf000 CR3: 000000000866d006 CR4: 00000000001606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock_sched_held+0x8d/0x120 kernel/rcu/update.c:113 trace_workqueue_execute_start include/trace/events/workqueue.h:89 [inline] process_one_work+0xecb/0x15a0 kernel/workqueue.c:2151 worker_thread+0x85/0xb60 kernel/workqueue.c:2295 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415