updating oom_score_adj for 7633 (syz-executor273) from 1000 to 1000 because it shares mm with 7635 (syz-executor273). Report if this is unexpected. updating oom_score_adj for 7637 (syz-executor273) from 1000 to 1000 because it shares mm with 7640 (syz-executor273). Report if this is unexpected. INFO: task syz-executor273:3839 blocked for more than 140 seconds. Not tainted 4.9.141+ #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor273 D29544 3839 2490 0x00000000 ffff8801d7d6df00 0000000000000000 ffff8801d8003700 ffff8801da6b2f80 ffff8801db721018 ffff8801d7c87a00 ffffffff828075c2 ffff8801d7c87a10 ffffffff83cc2f20 ffff8801d99987ff 00000000000061b9 ffff8801db7218f0 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3553 [] schedule_timeout+0x735/0xe20 kernel/time/timer.c:1771 [] down_read_failed drivers/tty/tty_ldsem.c:241 [inline] [] __ldsem_down_read_nested+0x33c/0x610 drivers/tty/tty_ldsem.c:332 [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 [] tty_ldisc_ref_wait+0x25/0x80 drivers/tty/tty_ldisc.c:275 [] tty_poll+0xc5/0x190 drivers/tty/tty_io.c:2232 [] ep_item_poll fs/eventpoll.c:811 [inline] [] ep_insert fs/eventpoll.c:1347 [inline] [] SYSC_epoll_ctl fs/eventpoll.c:1975 [inline] [] SyS_epoll_ctl+0x119f/0x25d0 fs/eventpoll.c:1861 [] do_syscall_64+0x19f/0x550 arch/x86/entry/common.c:285 [] 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: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/2029: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/3838: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/3839: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4496: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/4497: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4500: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/4501: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4618: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/4620: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4638: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4639: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/4834: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/4835: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/5502: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/5503: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/5506: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/5507: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/7438: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/7439: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/7653: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+.+.}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 2 locks held by syz-executor273/7654: #0: (&ep->mtx){+.+.+.}, at: [] SYSC_epoll_ctl fs/eventpoll.c:1939 [inline] #0: (&ep->mtx){+.+.+.}, at: [] SyS_epoll_ctl+0x879/0x25d0 fs/eventpoll.c:1861 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 2 locks held by syz-executor273/7655: #0: (&tty->legacy_mutex){+.+.+.}, at: [] tty_lock+0x6a/0xd0 drivers/tty/tty_mutex.c:18 #1: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_write+0x32/0x37 drivers/tty/tty_ldsem.c:393 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.141+ #1 ffff8801d9907d08 ffffffff81b42e79 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810983b0 ffff8801d9907d40 ffffffff81b4df89 0000000000000000 0000000000000000 0000000000000002 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.0+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12c/0x151 lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6ad/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff82816496