INFO: task syz-executor.3:20002 blocked for more than 143 seconds. Not tainted 5.5.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28160 20002 9037 0x00000004 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:1036 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1106 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1121 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 __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 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 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: 0033:0x4144a1 Code: Bad RIP value. RSP: 002b:0000000000a6fbf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 000000000000000d RCX: 00000000004144a1 RDX: 0000000000000000 RSI: 0000000000001eea RDI: 000000000000000c RBP: 0000000000000001 R08: 000000000cdddeee R09: ffffffffffffffff R10: 0000000000a6fcd0 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000770368 R15: 000000000075bfd4 Showing all locks held in the system: 1 lock held by khungtaskd/1114: #0: ffffffff899a56c0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5334 1 lock held by rsyslogd/8899: #0: ffff88809e6843e0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/8989: #0: ffff8880a4f28090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8991: #0: ffff8880a2418090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000182b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8992: #0: ffff8880a8154090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8993: #0: ffff888097890090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000184b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8994: #0: ffff8880a76fb090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000186b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/8995: #0: ffff888099525090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900017ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/20002: #0: ffff8880a4b05070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a4b05070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 2 locks held by syz-executor.3/20003: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1114 Comm: khungtaskd Not tainted 5.5.0-rc1-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: 20003 Comm: syz-executor.3 Not tainted 5.5.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x50 kernel/kcov.c:193 Code: 25 c0 1e 02 00 65 8b 15 e4 f2 8c 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 80 13 00 00 83 fa 02 75 20 48 8b 88 88 13 00 00 <8b> 80 84 13 00 00 48 8b 11 48 83 c2 01 48 39 d0 76 07 48 89 34 d1 RSP: 0018:ffffc90001a16d78 EFLAGS: 00000246 RAX: ffff8880a3788240 RBX: 0000000000000000 RCX: ffffc9000ff78000 RDX: 0000000000000002 RSI: ffffffff83b49266 RDI: 0000000000000005 RBP: ffffc90001a16d78 R08: ffff8880a3788240 R09: 0000000000000040 R10: ffffed1014960ddb R11: ffff8880a4b06edf R12: 0000000000000050 R13: 0000000000000030 R14: ffff8880000a0000 R15: ffff8880000a0100 FS: 00007fde1591a700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f001f24c140 CR3: 0000000098c05000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:64 [inline] bitfill_aligned+0x106/0x210 drivers/video/fbdev/core/cfbfillrect.c:35 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 fbcon_switch+0x556/0x17f0 drivers/video/fbdev/core/fbcon.c:2287 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: 0033:0x45a909 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:00007fde15919c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a909 RDX: 0000000020000040 RSI: 0000000000004601 RDI: 000000000000000d RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fde1591a6d4 R13: 00000000004c310d R14: 00000000004d83d8 R15: 00000000ffffffff