bisecting fixing commit since a1b977b49b66c75e6c51a515f6700371ae720217 building syzkaller on fc7735a27949755327024847e12dcc1b868bcb99 testing commit a1b977b49b66c75e6c51a515f6700371ae720217 with gcc (GCC) 8.1.0 kernel signature: 9c505f09d8912d8206b7237ed8cc5bddaa4ef711095d2c84414f20f1324545a4 all runs: crashed: INFO: task hung in sync_inodes_sb testing current HEAD 675cc038067f0e530471c56a7442935f84669d95 testing commit 675cc038067f0e530471c56a7442935f84669d95 with gcc (GCC) 8.1.0 kernel signature: 404fa7c44b7c66086c93cebbea46dee9d0d43e8cc3df0911816cb1b752552179 all runs: crashed: INFO: task hung in sync_inodes_sb revisions tested: 2, total time: 32m42.408746196s (build: 18m13.360006591s, test: 13m48.232241456s) the crash still happens on HEAD commit msg: Linux 4.19.167 crash: INFO: task hung in sync_inodes_sb Bluetooth: hci4: command 0x0406 tx timeout Bluetooth: hci3: command 0x0406 tx timeout Bluetooth: hci1: command 0x0406 tx timeout Bluetooth: hci5: command 0x0406 tx timeout Bluetooth: hci2: command 0x0406 tx timeout INFO: task syz-executor.0:5984 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D23512 5984 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007ffebea51b08 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffebea51bb0 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffebea52c40 R13: 0000000001c56a60 R14: 0000000000000000 R15: 00007ffebea52c40 INFO: task syz-executor.2:5987 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D23848 5987 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007ffca9cde858 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffca9cde900 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffca9cdf990 R13: 00000000017c4a60 R14: 0000000000000000 R15: 00007ffca9cdf990 INFO: task syz-executor.3:5988 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D23320 5988 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007ffd65576378 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffd65576420 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffd655774b0 R13: 0000000002dcaa60 R14: 0000000000000000 R15: 00007ffd655774b0 INFO: task syz-executor.5:5991 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D23800 5991 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007ffdee532a88 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffdee532b30 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffdee533bc0 R13: 0000000002a92a60 R14: 0000000000000000 R15: 00007ffdee533bc0 INFO: task syz-executor.1:5992 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D23776 5992 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007fffdebef8e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007fffdebef990 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007fffdebf0a20 R13: 000000000216da60 R14: 0000000000000000 R15: 00007fffdebf0a20 INFO: task syz-executor.4:5993 blocked for more than 140 seconds. Not tainted 4.19.167-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D23800 5993 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:2483 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x114/0x1f0 fs/sync.c:67 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+0x13f/0x160 fs/super.c:360 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: 0033:0x460887 Code: Bad RIP value. RSP: 002b:00007ffded626068 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffded626110 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffded6271a0 R13: 0000000001e89a60 R14: 0000000000000000 R15: 00007ffded6271a0 Showing all locks held in the system: 2 locks held by kworker/u4:0/7: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 000000009b973604 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 2 locks held by kworker/u4:2/31: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 0000000054a37c59 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 2 locks held by kworker/u4:4/919: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 00000000a7e591ac ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 1 lock held by khungtaskd/1096: #0: 000000008bdf6cca (rcu_read_lock){....}, at: debug_show_all_locks+0x5b/0x27a kernel/locking/lockdep.c:4442 2 locks held by kworker/u4:5/3640: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 000000001bc6cff1 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 1 lock held by in:imklog/5590: #0: 000000004ba1cef1 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xa7/0xd0 fs/file.c:767 2 locks held by syz-executor.0/5984: #0: 00000000bc622cef (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 00000000f17a0d12 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000f17a0d12 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by syz-executor.2/5987: #0: 00000000e5fbf558 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 000000009f8cb3dd (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 000000009f8cb3dd (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by syz-executor.3/5988: #0: 0000000055f2a62a (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 00000000d4cc2625 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000d4cc2625 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by syz-executor.5/5991: #0: 00000000146fdef6 (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 00000000a9949542 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000a9949542 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by syz-executor.1/5992: #0: 000000001ec053ae (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 0000000001751547 (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 0000000001751547 (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by syz-executor.4/5993: #0: 000000001f20246f (&type->s_umount_key#50){+.+.}, at: deactivate_super+0x137/0x160 fs/super.c:359 #1: 00000000cda073fe (&bdi->wb_switch_rwsem){+.+.}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:338 [inline] #1: 00000000cda073fe (&bdi->wb_switch_rwsem){+.+.}, at: sync_inodes_sb+0x16a/0x8e0 fs/fs-writeback.c:2481 2 locks held by kworker/u4:7/7351: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 000000004aa3bc93 ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 2 locks held by kworker/u4:8/7365: #0: 0000000068c8202c ((wq_completion)"writeback"){+.+.}, at: process_one_work+0x6e8/0x15a0 kernel/workqueue.c:2126 #1: 0000000075dace7e ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: process_one_work+0x71b/0x15a0 kernel/workqueue.c:2130 3 locks held by kworker/u4:9/7540: #0: 000000003d22f1ea (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9701 [inline] #0: 000000003d22f1ea (&rq->lock){-.-.}, at: pick_next_task_fair+0xffb/0x1530 kernel/sched/fair.c:6840 #1: 000000008bdf6cca (rcu_read_lock){....}, at: cpu_of kernel/sched/sched.h:921 [inline] #1: 000000008bdf6cca (rcu_read_lock){....}, at: __update_idle_core+0x3c/0x3f0 kernel/sched/fair.c:6057 #2: 000000008bdf6cca (rcu_read_lock){....}, at: batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:417 [inline] #2: 000000008bdf6cca (rcu_read_lock){....}, at: batadv_nc_worker+0xbc/0x630 net/batman-adv/network-coding.c:730 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1096 Comm: khungtaskd Not tainted 4.19.167-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/0x22a lib/dump_stack.c:118 nmi_cpu_backtrace.cold.0+0x3c/0x78 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0xf5/0x119 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7540 Comm: kworker/u4:9 Not tainted 4.19.167-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:skb_end_pointer include/linux/skbuff.h:1272 [inline] RIP: 0010:pskb_expand_head+0x1ba/0xd80 net/core/skbuff.c:1477 Code: c0 41 8b 95 c8 00 00 00 48 89 c7 48 89 45 a8 e8 ec 8a 0f fc 48 8b 55 d0 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 <0f> 85 1a 0a 00 00 48 89 da 49 8b 8d d0 00 00 00 48 b8 00 00 00 00 RSP: 0018:ffff8881d6367b98 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ffff8881e4cc7d8c RCX: 0000000000000000 RDX: 1ffff1103c998fb2 RSI: ffff8881ecf00ee6 RDI: ffff8881f28b1b66 RBP: ffff8881d6367c28 R08: ffffed103e51636d R09: ffffed103e516360 R10: ffffed103e51636c R11: ffff8881f28b1b65 R12: ffff8881e4cc7d4e R13: ffff8881e4cc7cc0 R14: 0000000000000280 R15: 0000000000480020 FS: 0000000000000000(0000) GS:ffff8881f6600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f937b50d000 CR3: 000000000866d005 CR4: 00000000001606f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __skb_cow include/linux/skbuff.h:2963 [inline] skb_cow_head include/linux/skbuff.h:2997 [inline] batadv_skb_head_push+0xd7/0x230 net/batman-adv/soft-interface.c:86 batadv_send_skb_packet+0xeb/0x5e0 net/batman-adv/send.c:98 batadv_send_broadcast_skb+0x10/0x20 net/batman-adv/send.c:139 batadv_iv_ogm_send_to_if net/batman-adv/bat_iv_ogm.c:578 [inline] batadv_iv_ogm_emit net/batman-adv/bat_iv_ogm.c:604 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x5d2/0x830 net/batman-adv/bat_iv_ogm.c:1857 process_one_work+0x7b9/0x15a0 kernel/workqueue.c:2155 worker_thread+0x85/0xb60 kernel/workqueue.c:2298 kthread+0x347/0x410 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415