INFO: task syz-executor.4:2122 blocked for more than 140 seconds. Not tainted 4.9.180+ #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28504 2122 2071 0x00000004 0000000000000087 ffff8801d1f7df00 ffff8801cf112c00 ffff8801db621000 ffff8801d1294740 ffff8801db621018 ffff880195c2f680 ffffffff8280932e 0000000000000246 ffff8801d1f7df00 0000000000000000 ffff8801db6218f0 Call Trace: [<000000001f4c8f7c>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<0000000006d03aae>] __rt_mutex_slowlock+0x99/0x290 kernel/locking/rtmutex.c:1221 [<00000000e988c95d>] rt_mutex_slowlock+0x199/0x4c0 kernel/locking/rtmutex.c:1293 [<00000000b61b23f7>] rt_mutex_fastlock kernel/locking/rtmutex.c:1439 [inline] [<00000000b61b23f7>] rt_mutex_lock+0x2d/0x40 kernel/locking/rtmutex.c:1499 [<00000000df7d4b5b>] process_notifier drivers/misc/uid_sys_stats.c:636 [inline] [<00000000df7d4b5b>] process_notifier+0x96/0x670 drivers/misc/uid_sys_stats.c:625 [<00000000b505b108>] notifier_call_chain+0xb4/0x1d0 kernel/notifier.c:93 [<000000003ea78b02>] __blocking_notifier_call_chain kernel/notifier.c:317 [inline] [<000000003ea78b02>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] [<000000003ea78b02>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] [<000000003ea78b02>] blocking_notifier_call_chain+0x80/0xa0 kernel/notifier.c:325 [<00000000f1fee03a>] profile_task_exit+0x1f/0x30 kernel/profile.c:140 [<0000000032f567c3>] do_exit+0x90/0x2aa0 kernel/exit.c:744 [<0000000081d36244>] do_group_exit+0x111/0x300 kernel/exit.c:945 [<00000000c126fc3c>] get_signal+0x348/0x1aa0 kernel/signal.c:2380 [<0000000093cf1e07>] do_signal+0x9c/0x1920 arch/x86/kernel/signal.c:812 [<000000006750e43c>] exit_to_usermode_loop+0x11c/0x160 arch/x86/entry/common.c:159 [<00000000d33ce62f>] prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] [<00000000d33ce62f>] syscall_return_slowpath arch/x86/entry/common.c:266 [inline] [<00000000d33ce62f>] do_syscall_64+0x3ab/0x5c0 arch/x86/entry/common.c:293 [<00000000724fe30e>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<00000000acc88764>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000acc88764>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<0000000055bad95a>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 2 locks held by getty/2039: #0: (&tty->ldisc_sem){++++++}, at: [<000000004ad81db6>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [<000000003b7f82ad>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.4/2122: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.5/2123: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.2/2124: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.3/12303: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by kworker/dying/12997: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by kworker/dying/21820: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/23990: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/23993: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/23998: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/24016: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/24017: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by getty/24022: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.3/24144: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.3/24148: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.2/24171: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.2/24172: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.4/24174: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.4/24177: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.5/24178: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.5/24179: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 1 lock held by syz-executor.5/24180: #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:316 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain kernel/notifier.c:328 [inline] #0: ((task_exit_notifier).rwsem){.+.+..}, at: [<000000000ef830f9>] blocking_notifier_call_chain+0x6a/0xa0 kernel/notifier.c:325 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.180+ #3 ffff8801d98d7cc8 ffffffff81b577f1 0000000000000001 0000000000000000 0000000000000001 ffffffff81099901 dffffc0000000000 ffff8801d98d7d00 ffffffff81b62a8c 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<000000008712d038>] __dump_stack lib/dump_stack.c:15 [inline] [<000000008712d038>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000d11be89b>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000f168511c>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000e6c9d7fc>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000271b8b8d>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000271b8b8d>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000271b8b8d>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000271b8b8d>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000059d5262>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000316bbf57>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff82818481