INFO: task syz-executor.1:4073 blocked for more than 143 seconds. Not tainted 5.8.0-rc2-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D26408 4073 6966 0x80004006 Call Trace: context_switch kernel/sched/core.c:3430 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4155 schedule+0xd0/0x2a0 kernel/sched/core.c:4230 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235 __down_write kernel/locking/rwsem.c:1389 [inline] down_write+0x137/0x150 kernel/locking/rwsem.c:1532 unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1855 bcm_release+0x94/0x750 net/can/bcm.c:1474 __sock_release+0xcd/0x280 net/socket.c:605 sock_close+0x18/0x20 net/socket.c:1278 __fput+0x33c/0x880 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xb72/0x2a40 kernel/exit.c:805 do_group_exit+0x125/0x310 kernel/exit.c:903 get_signal+0x428/0x1fc0 kernel/signal.c:2739 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810 exit_to_usermode_loop arch/x86/entry/common.c:212 [inline] __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:246 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:368 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb19 Code: Bad RIP value. RSP: 002b:00007f85f0ac0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029 RAX: 0000000000000004 RBX: 00000000005082c0 RCX: 000000000045cb19 RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000bb3 R14: 00000000004ce160 R15: 00007f85f0ac16d4 Showing all locks held in the system: 3 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/1150: #0: ffffffff89bbe640 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6489: #0: ffff8880a64338b0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/6731: #0: ffff88809abb2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc900013a42e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.1/4073: #0: ffff88808c958210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:799 [inline] #0: ffff88808c958210 (&sb->s_type->i_mutex_key#14){+.+.}-{3:3}, at: __sock_release+0x86/0x280 net/socket.c:604 #1: ffffffff8a7a3630 (pernet_ops_rwsem){++++}-{3:3}, at: unregister_netdevice_notifier+0x1e/0x170 net/core/dev.c:1855 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1150 Comm: khungtaskd Not tainted 5.8.0-rc2-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 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+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 20653 Comm: kworker/u4:6 Not tainted 5.8.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_nc_worker RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x60 kernel/kcov.c:197 Code: 5d be 03 00 00 00 e9 26 aa 23 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 48 8b 14 25 00 ff 01 00 <65> 8b 05 c0 ad 8e 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74 RSP: 0018:ffffc9001cd4fc78 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff87c93a20 RDX: ffff8881a9a8a000 RSI: ffff8881a9a8a000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000000 R09: ffff8880ae736cdb R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: dffffc0000000000 R15: 000000000000034b FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ff45d96b000 CR3: 000000009dc3e000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: rcu_read_unlock include/linux/rcupdate.h:684 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:411 [inline] batadv_nc_worker+0x769/0xe50 net/batman-adv/network-coding.c:718 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293