bisecting fixing commit since 3dd0130f2430decf0cb001b452824515436986d2 building syzkaller on 4a77ae0bdc5cd75ebe88ce7c896aae6bbf457a29 testing commit 3dd0130f2430decf0cb001b452824515436986d2 with gcc (GCC) 8.1.0 kernel signature: ce5c1db10c359a890a9563ed68b1d292d5a2906cda5f7898b2a9718c3df96e6b all runs: crashed: INFO: task hung in sync_inodes_sb testing current HEAD d652d5f1eeeb06046009f4fcb9b4542249526916 testing commit d652d5f1eeeb06046009f4fcb9b4542249526916 with gcc (GCC) 8.1.0 kernel signature: e4890dc18dfb7f47f96c0198c772df0b012e82b3c7d0ef92bd0c3079fe34e852 all runs: crashed: INFO: task hung in sync_inodes_sb revisions tested: 2, total time: 24m8.384886102s (build: 10m4.855765998s, test: 13m25.072127977s) the crash still happens on HEAD commit msg: drm/edid: fix objtool warning in drm_cvt_modes() crash: INFO: task hung in sync_inodes_sb INFO: task syz-executor.2:6198 blocked for more than 143 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.2 state:D stack:11552 pid: 6198 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007fff36bf1358 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fff36bf1400 RBP: 0000000000000006 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007fff36bf2490 R13: 0000000002adea60 R14: 0000000000000000 R15: 00007fff36bf2490 INFO: task syz-executor.4:6200 blocked for more than 143 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:11624 pid: 6200 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007ffd4e96c558 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffd4e96c600 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffd4e96d690 R13: 0000000003176a60 R14: 0000000000000000 R15: 00007ffd4e96d690 INFO: task syz-executor.3:6201 blocked for more than 143 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:11448 pid: 6201 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007ffe2100c718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffe2100c7c0 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffe2100d850 R13: 00000000035e8a60 R14: 0000000000000000 R15: 00007ffe2100d850 INFO: task syz-executor.0:6204 blocked for more than 143 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:11752 pid: 6204 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007ffdaab55868 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffdaab55910 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffdaab569a0 R13: 0000000002820a60 R14: 0000000000000000 R15: 00007ffdaab569a0 INFO: task syz-executor.5:6205 blocked for more than 144 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:11744 pid: 6205 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007ffec1f0eb28 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffec1f0ebd0 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffec1f0fc60 R13: 0000000002107a60 R14: 0000000000000000 R15: 00007ffec1f0fc60 INFO: task syz-executor.1:6206 blocked for more than 144 seconds. Not tainted 5.10.0-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:11624 pid: 6206 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4327 [inline] __schedule+0x429/0x9b0 kernel/sched/core.c:5078 schedule+0x38/0xe0 kernel/sched/core.c:5157 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x4a0 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1393 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x229/0x250 kernel/entry/common.c:201 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline] syscall_exit_to_user_mode+0x40/0x80 kernel/entry/common.c:302 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 RSP: 002b:00007ffcf3f4ba78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffcf3f4bb20 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffcf3f4cbb0 R13: 0000000001909a60 R14: 0000000000000000 R15: 00007ffcf3f4cbb0 Showing all locks held in the system: 2 locks held by kworker/u4:1/22: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc900000dbe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc900000dbe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc900000dbe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 2 locks held by kworker/u4:3/185: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc9000056be70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc9000056be70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc9000056be70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 1 lock held by khungtaskd/1159: #0: ffffffff84a113e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x1a6 kernel/locking/lockdep.c:6255 2 locks held by kworker/u4:4/2534: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc900049ebe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc900049ebe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc900049ebe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 2 locks held by kworker/u4:5/2719: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc90004e13e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90004e13e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90004e13e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 5 locks held by kworker/1:2/2730: #0: ffff888237d2de58 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x45c/0x640 kernel/sched/fair.c:10642 #1: ffff888237d18fc8 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x143/0x180 kernel/sched/psi.c:833 #2: ffff888237d1d7d8 (&base->lock){..-.}-{2:2}, at: lock_timer_base+0x70/0xc0 kernel/time/timer.c:944 #3: ffffffff86a87d90 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_object_activate+0xb0/0x240 lib/debugobjects.c:656 #4: ffffffff86a807b8 (&obj_hash[i].lock){-.-.}-{2:2}, at: __debug_check_no_obj_freed lib/debugobjects.c:975 [inline] #4: ffffffff86a807b8 (&obj_hash[i].lock){-.-.}-{2:2}, at: debug_check_no_obj_freed+0x8e/0x200 lib/debugobjects.c:1018 1 lock held by in:imklog/5820: #0: ffff8881092e70f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x45/0x50 fs/file.c:947 2 locks held by syz-executor.2/6198: #0: ffff8881181cd0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888103693708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888103693708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by syz-executor.4/6200: #0: ffff888117fe90e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888100f8f708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888100f8f708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by syz-executor.3/6201: #0: ffff8881181160e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888104305708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888104305708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by syz-executor.0/6204: #0: ffff8881185650e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff8881040fe708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff8881040fe708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by syz-executor.5/6205: #0: ffff88811801d0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff88810406e708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff88810406e708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by syz-executor.1/6206: #0: ffff88811826d0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888103fc2708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888103fc2708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x4a0 fs/fs-writeback.c:2557 2 locks held by kworker/u4:6/6491: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc90000583e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90000583e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90000583e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 2 locks held by kworker/u4:7/7578: #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100aeb538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 #1: ffffc90001c23e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90001c23e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90001c23e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x207/0x610 kernel/workqueue.c:2246 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1159 Comm: khungtaskd Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0xa3/0xc8 lib/dump_stack.c:120 nmi_cpu_backtrace.cold.8+0x68/0x82 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0xd5/0xf0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0x5f1/0x6f0 kernel/hung_task.c:294 kthread+0x145/0x170 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:match_held_lock+0xa/0x160 kernel/locking/lockdep.c:4894 Code: 00 50 03 00 48 01 f8 c3 cc cc cc cc cc cc cc cc 48 8b 34 24 48 c7 c7 90 2d 32 84 e8 7c b9 dc ff 48 39 77 10 0f 84 97 00 00 00 <66> f7 47 22 f0 ff 74 4b 48 83 ec 08 48 8b 46 08 48 85 c0 0f 84 84 RSP: 0018:ffffc90000057d38 EFLAGS: 00000083 RAX: 0000000000000005 RBX: ffff88810026eb70 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff84a11360 RDI: ffff88810026eb70 RBP: ffffffff84a11360 R08: 0000000000000000 R09: 0000000000000000 R10: ffff88810026eb48 R11: 0000000000000000 R12: ffff88810026e1c0 R13: ffff88810026eb48 R14: 00000000ffffffff R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8dfcdeb000 CR3: 000000010921c004 CR4: 00000000001706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __lock_is_held kernel/locking/lockdep.c:5185 [inline] lock_is_held_type+0xd0/0x160 kernel/locking/lockdep.c:5476 lock_is_held include/linux/lockdep.h:271 [inline] rcu_read_lock_sched_held+0x58/0x80 kernel/rcu/update.c:123 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x300/0x440 kernel/locking/lockdep.c:5408 rcu_lock_acquire include/linux/rcupdate.h:253 [inline] rcu_read_lock include/linux/rcupdate.h:642 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:404 [inline] batadv_nc_worker+0x6a/0x260 net/batman-adv/network-coding.c:715 process_one_work+0x293/0x610 kernel/workqueue.c:2275 worker_thread+0x38/0x380 kernel/workqueue.c:2421 kthread+0x145/0x170 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296