INFO: task syz-executor.2:15900 blocked for more than 143 seconds. Not tainted 5.5.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D26736 15900 9419 0x80004002 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x176/0x2c0 kernel/locking/semaphore.c:237 down+0x64/0x90 kernel/locking/semaphore.c:61 console_lock+0x29/0x80 kernel/printk/printk.c:2289 con_shutdown+0x41/0x90 drivers/tty/vt/vt.c:3277 release_tty+0xd3/0x470 drivers/tty/tty_io.c:1514 tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1629 tty_release+0xbcb/0xe90 drivers/tty/tty_io.c:1789 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xba9/0x2f50 kernel/exit.c:801 do_group_exit+0x135/0x360 kernel/exit.c:899 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45af49 Code: e8 3c 1f 00 00 eb aa cc cc cc cc cc cc cc cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 40 48 83 ec 28 48 89 6c 24 20 48 <8d> 6c 24 20 48 8b 42 10 48 8b 4a 18 48 8b 52 08 48 89 14 24 48 89 RSP: 002b:00007fb31db2dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: 000000000000017a RBX: 0000000000000005 RCX: 000000000045af49 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000049b96b00 RBP: 000000000075bf20 R08: 0000000020000300 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb31db2e6d4 R13: 00000000004c1701 R14: 00000000004d6660 R15: 00000000ffffffff INFO: task syz-executor.0:15939 blocked for more than 143 seconds. Not tainted 5.5.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28552 15939 9414 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 chrdev_open+0x245/0x6b0 fs/char_dev.c:414 do_dentry_open+0x4e6/0x1380 fs/open.c:797 vfs_open+0xa0/0xd0 fs/open.c:914 do_last fs/namei.c:3420 [inline] path_openat+0x10df/0x4500 fs/namei.c:3537 do_filp_open+0x1a1/0x280 fs/namei.c:3567 do_sys_open+0x3fe/0x5d0 fs/open.c:1097 __do_sys_open fs/open.c:1115 [inline] __se_sys_open fs/open.c:1110 [inline] __x64_sys_open+0x7e/0xc0 fs/open.c:1110 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414ce1 Code: 8b 44 24 24 44 8b 44 24 20 48 8b 5c 24 18 48 8b 54 24 70 48 8b b4 24 90 00 00 00 48 8b bc 24 98 00 00 00 4c 8b 8c 24 88 00 00 <00> 4c 8b 54 24 48 e9 45 ff ff ff 48 89 4c 24 50 44 89 44 24 34 48 RSP: 002b:00007fadf21627a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000414ce1 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 00007fadf21627d0 RBP: 000000000075bfc8 R08: 0000000000000000 R09: 000000000000000e R10: 0000000000000064 R11: 0000000000000293 R12: 00007fadf21636d4 R13: 00000000004cc243 R14: 00000000004e6fb0 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1123: #0: ffffffff899a5340 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/9281: #0: ffff88809b84bde0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9371: #0: ffff8880a66c9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000193b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9372: #0: ffff8880a8624090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9373: #0: ffff888098656090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000199b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9374: #0: ffff888095ddc090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000196b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9375: #0: ffff8880980ec090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9376: #0: ffff88809a7bd090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000194b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9377: #0: ffff88808dc18090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000190b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/15900: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_release_struct+0x31/0x50 drivers/tty/tty_io.c:1628 1 lock held by syz-executor.0/15939: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 2 locks held by syz-executor.3/15937: 1 lock held by syz-executor.4/15949: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.5/15950: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.1/15974: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 1 lock held by syz-executor.2/15994: #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open_by_driver drivers/tty/tty_io.c:1951 [inline] #0: ffffffff89eea8c0 (tty_mutex){+.+.}, at: tty_open+0x3cb/0xbb0 drivers/tty/tty_io.c:2035 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1123 Comm: khungtaskd Not tainted 5.5.0-rc5-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b 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:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 15937 Comm: syz-executor.3 Not tainted 5.5.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x1/0x50 kernel/kcov.c:180 Code: cc cc cc cc cc cc cc cc cc 65 48 8b 04 25 c0 1e 02 00 48 8b 80 98 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 84 f7 8c 7e 81 e2 00 RSP: 0018:ffffc90001a572c8 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff83c1643f RDX: 0000000000001400 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffffc90001a57318 R08: ffff8880a8884100 R09: 0000000000000040 R10: ffffed1014791c4b R11: ffff8880a3c8e25f R12: 0000000000001400 R13: 0000000000000040 R14: ffff8880000a0000 R15: 0000000000000000 FS: 00007f75c7512700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00005bc80 CR3: 00000000a0b7a000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: cfb_fillrect+0x423/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104 fb_ioctl+0xe6/0x130 drivers/video/fbdev/core/fbmem.c:1180 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45af49 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f75c7511c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045af49 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f75c75126d4 R13: 00000000004c3903 R14: 00000000004d9f18 R15: 00000000ffffffff