INFO: task syz-executor.4:24998 blocked for more than 140 seconds. Not tainted 4.19.211-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D29184 24998 8110 0x00000004 Call Trace: context_switch kernel/sched/core.c:2828 [inline] __schedule+0x887/0x2040 kernel/sched/core.c:3517 schedule+0x8d/0x1b0 kernel/sched/core.c:3561 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common+0x29c/0x470 kernel/sched/completion.c:115 __flush_work+0x4bb/0x8b0 kernel/workqueue.c:2926 n_tty_read+0xabc/0x1950 drivers/tty/n_tty.c:2197 tty_read+0x183/0x290 drivers/tty/tty_io.c:867 __vfs_read+0xf7/0x750 fs/read_write.c:416 vfs_read+0x194/0x3c0 fs/read_write.c:452 ksys_read+0x12b/0x2a0 fs/read_write.c:579 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fd898bd1669 Code: Bad RIP value. RSP: 002b:00007fd897503168 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 00007fd898cf3120 RCX: 00007fd898bd1669 RDX: 0000000000002020 RSI: 0000000020000180 RDI: 0000000000000005 RBP: 00007fd898c2c560 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffefeefa6f R14: 00007fd897503300 R15: 0000000000022000 Showing all locks held in the system: 2 locks held by ksoftirqd/0/9: #0: 00000000e01cf653 (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1826 [inline] #0: 00000000e01cf653 (&rq->lock){-.-.}, at: __schedule+0x1f9/0x2040 kernel/sched/core.c:3455 #1: 00000000731a6c29 (&obj_hash[i].lock){-.-.}, at: __debug_check_no_obj_freed lib/debugobjects.c:776 [inline] #1: 00000000731a6c29 (&obj_hash[i].lock){-.-.}, at: debug_check_no_obj_freed+0xb5/0x490 lib/debugobjects.c:817 1 lock held by khungtaskd/1570: #0: 00000000908350db (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4441 1 lock held by in:imklog/7765: #0: 00000000382a188f (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767 5 locks held by kworker/u4:8/10476: 2 locks held by agetty/6668: #0: 000000009cc682e2 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000009724164f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154 2 locks held by syz-executor.4/24998: #0: 000000002010f411 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000008c40b9fa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154 2 locks held by syz-executor.3/30984: #0: 00000000c0747967 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 000000008d5c0e43 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock drivers/tty/tty_io.c:886 [inline] #1: 000000008d5c0e43 (&tty->atomic_write_lock){+.+.}, at: do_tty_write drivers/tty/tty_io.c:909 [inline] #1: 000000008d5c0e43 (&tty->atomic_write_lock){+.+.}, at: tty_write+0x24e/0x810 drivers/tty/tty_io.c:1044 2 locks held by syz-executor.0/30982: #0: 000000005236f785 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 0000000081d1cbba (&tty->atomic_write_lock){+.+.}, at: tty_write_lock drivers/tty/tty_io.c:886 [inline] #1: 0000000081d1cbba (&tty->atomic_write_lock){+.+.}, at: do_tty_write drivers/tty/tty_io.c:909 [inline] #1: 0000000081d1cbba (&tty->atomic_write_lock){+.+.}, at: tty_write+0x24e/0x810 drivers/tty/tty_io.c:1044 2 locks held by syz-executor.2/30999: #0: 00000000a1fa8c7c (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272 #1: 00000000f70116d9 (&tty->atomic_write_lock){+.+.}, at: tty_write_lock drivers/tty/tty_io.c:886 [inline] #1: 00000000f70116d9 (&tty->atomic_write_lock){+.+.}, at: do_tty_write drivers/tty/tty_io.c:909 [inline] #1: 00000000f70116d9 (&tty->atomic_write_lock){+.+.}, at: tty_write+0x24e/0x810 drivers/tty/tty_io.c:1044 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1570 Comm: khungtaskd Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1a6/0x1f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline] watchdog+0x991/0xe60 kernel/hung_task.c:287 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 30989 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x50 kernel/kcov.c:97 Code: ff 48 89 df e8 11 dd 35 00 e9 ab fe ff ff 4c 89 ef e8 04 dd 35 00 e9 23 fe ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <48> 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e 81 e2 RSP: 0018:ffff8880191ef700 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffff8880937f4a44 RBP: ffffea00011b22c0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: dead000000000100 R15: 00007fbba2840000 FS: 0000000000000000(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f50e7703000 CR3: 0000000009e6d000 CR4: 00000000003406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: debug_smp_processor_id+0x5/0x20 lib/smp_processor_id.c:56 rcu_dynticks_curr_cpu_in_eqs kernel/rcu/tree.c:348 [inline] rcu_is_watching+0x12/0xc0 kernel/rcu/tree.c:1025 rcu_read_unlock include/linux/rcupdate.h:677 [inline] __unlock_page_memcg+0x72/0x100 mm/memcontrol.c:1955 page_remove_rmap+0xe5/0x120 mm/rmap.c:1297 zap_pte_range mm/memory.c:1350 [inline] zap_pmd_range mm/memory.c:1463 [inline] zap_pud_range mm/memory.c:1492 [inline] zap_p4d_range mm/memory.c:1513 [inline] unmap_page_range+0x147d/0x2c50 mm/memory.c:1534 unmap_single_vma+0x198/0x300 mm/memory.c:1579 unmap_vmas+0xa9/0x180 mm/memory.c:1609 exit_mmap+0x2b9/0x530 mm/mmap.c:3093 __mmput kernel/fork.c:1016 [inline] mmput+0x14e/0x4a0 kernel/fork.c:1037 exit_mm kernel/exit.c:549 [inline] do_exit+0xaec/0x2be0 kernel/exit.c:857 do_group_exit+0x125/0x310 kernel/exit.c:967 get_signal+0x3f2/0x1f70 kernel/signal.c:2589 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:799 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:271 [inline] do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fbba3038669 Code: Bad RIP value. RSP: 002b:00007fbba198b218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fbba315a058 RCX: 00007fbba3038669 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fbba315a058 RBP: 00007fbba315a050 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fbba315a05c R13: 00007fff72283fbf R14: 00007fbba198b300 R15: 0000000000022000