INFO: task syz-executor.3:4063 blocked for more than 143 seconds. Not tainted 5.7.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28392 4063 7383 0x00000004 Call Trace: context_switch kernel/sched/core.c:3367 [inline] __schedule+0x937/0x1ff0 kernel/sched/core.c:4083 set_irq_regs arch/x86/include/asm/irq_regs.h:27 [inline] smp_apic_timer_interrupt+0x1b6/0x600 arch/x86/kernel/apic/apic.c:1142 __sched_text_start+0x8/0x8 atomic_read include/asm-generic/atomic-instrumented.h:26 [inline] queued_spin_is_locked include/asm-generic/qspinlock.h:26 [inline] debug_spin_unlock kernel/locking/spinlock_debug.c:98 [inline] do_raw_spin_unlock+0x50/0x260 kernel/locking/spinlock_debug.c:138 schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4217 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 mutex_trylock+0x2c0/0x2c0 kernel/locking/mutex.c:126 atomic64_cmpxchg include/asm-generic/atomic-instrumented.h:1463 [inline] atomic_long_cmpxchg_release include/asm-generic/atomic-long.h:424 [inline] __mutex_unlock_slowpath+0xe2/0x660 kernel/locking/mutex.c:1249 spin_unlock include/linux/spinlock.h:393 [inline] chrdev_open+0xc4/0x5c0 fs/char_dev.c:402 lock_downgrade+0x840/0x840 kernel/locking/lockdep.c:4579 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 get_fb_info.part.0+0x80/0x80 drivers/video/fbdev/core/fbmem.c:68 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 cdev_put.part.0+0x50/0x50 fs/char_dev.c:364 security_file_open+0x84/0x410 security/security.c:1548 do_dentry_open+0x4ba/0x1290 fs/open.c:797 cdev_put.part.0+0x50/0x50 fs/char_dev.c:364 security_inode_permission+0xc4/0xf0 security/security.c:1253 chown_common+0x550/0x550 fs/open.c:629 inode_permission+0xab/0x500 fs/namei.c:450 do_open fs/namei.c:3229 [inline] path_openat+0x1e59/0x27d0 fs/namei.c:3346 path_lookupat.isra.0+0x530/0x530 fs/namei.c:2332 check_preemption_disabled lib/smp_processor_id.c:52 [inline] debug_smp_processor_id+0x2f/0x185 lib/smp_processor_id.c:57 perf_trace_lock+0xeb/0x4c0 include/trace/events/lock.h:39 lock_acquire+0x1f2/0x8f0 kernel/locking/lockdep.c:4934 __bfs+0x520/0x520 kernel/locking/lockdep.c:1539 do_filp_open+0x192/0x260 fs/namei.c:3373 may_open_dev+0xf0/0xf0 fs/namei.c:2821 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0x129/0x2e0 kernel/locking/spinlock_debug.c:113 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x24/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:393 [inline] __alloc_fd+0x46d/0x600 fs/file.c:534 do_sys_openat2+0x585/0x7d0 fs/open.c:1148 file_open_root+0x400/0x400 fs/open.c:1129 _copy_to_user+0x126/0x160 lib/usercopy.c:31 put_timespec64+0xcb/0x120 kernel/time/time.c:812 ns_to_kernel_old_timeval+0x100/0x100 kernel/time/time.c:521 do_sys_open+0xc3/0x140 fs/open.c:1164 filp_open+0x70/0x70 fs/open.c:1117 __ia32_sys_clock_settime+0x260/0x260 kernel/time/posix-timers.c:1410 trace_hardirqs_off_caller+0x55/0x230 kernel/trace/trace_preemptirq.c:73 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 Showing all locks held in the system: 3 locks held by kworker/u4:0/7: 1 lock held by khungtaskd/1141: #0: ffffffff899bea80 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/6762: #0: ffff8880a0e5adb0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/6956: #0: ffff8880a8335098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90002bbb2e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x220/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by agetty/6958: #0: ffff88809e593098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90002a952e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x220/0x1b30 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.3/4034: 1 lock held by syz-executor.3/4063: #0: ffff888218cad078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cad078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1141 Comm: khungtaskd Not tainted 5.7.0-rc6-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 lapic_can_unplug_cpu.cold+0x3b/0x3b nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 reset_hung_task_detector+0x30/0x30 kernel/hung_task.c:243 kthread+0x388/0x470 kernel/kthread.c:268 kthread_mod_delayed_work+0x1a0/0x1a0 kernel/kthread.c:1090 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4034 Comm: syz-executor.3 Not tainted 5.7.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x37/0x50 kernel/kcov.c:192 Code: e9 8e 7e 81 e2 00 01 1f 00 48 8b 34 24 75 2b 8b 90 d8 13 00 00 83 fa 02 75 20 48 8b 88 e0 13 00 00 8b 80 dc 13 00 00 48 8b 11 <48> 83 c2 01 48 39 d0 76 07 48 89 34 d1 48 89 11 c3 0f 1f 84 00 00 RSP: 0018:ffffc900073574d8 EFLAGS: 00000246 RAX: 0000000000040000 RBX: 0000000000000000 RCX: ffffc9000f858000 RDX: 000000000003ffff RSI: ffffffff83bf5b6c RDI: 0000000000000005 RBP: ffff8880000a0200 R08: ffff8880505a0380 R09: 0000000000000040 R10: ffff888218ca821f R11: ffffed1043195043 R12: 0000000000000050 R13: ffff8880000a0000 R14: 0000000000000000 R15: 0000000000000010 FS: 00007fbaea6b1700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0e2d29dba0 CR3: 000000009d95f000 CR4: 00000000001426f0 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+0xfc/0x200 drivers/video/fbdev/core/cfbfillrect.c:35 cfb_fillrect+0x418/0x7a0 drivers/video/fbdev/core/cfbfillrect.c:327 cfb_fillrect+0x7a0/0x7a0 drivers/video/fbdev/core/cfbfillrect.c:292 vga16fb_fillrect+0x68f/0x1960 drivers/video/fbdev/vga16fb.c:951 trace_hardirqs_on_thunk+0x1a/0x1c arch/x86/entry/thunk_64.S:41 bit_clear_margins+0x2d5/0x4a0 drivers/video/fbdev/core/bitblit.c:232 bit_bmove+0x210/0x210 drivers/video/fbdev/core/bitblit.c:59 fbcon_clear_margins+0x1de/0x240 drivers/video/fbdev/core/fbcon.c:1381 fbcon_switch+0xcde/0x16f0 drivers/video/fbdev/core/fbcon.c:2363 fbcon_set_def_font+0x370/0x370 drivers/video/fbdev/core/fbcon.c:2710 fbcon_cursor+0x477/0x650 drivers/video/fbdev/core/fbcon.c:1411 bit_clear+0x4e0/0x4e0 drivers/video/fbdev/core/fbcon.h:140 is_console_locked+0x5/0x10 kernel/printk/printk.c:2346 fbcon_set_origin+0x26/0x50 drivers/video/fbdev/core/fbcon.c:2938 redraw_screen+0x2ae/0x770 drivers/tty/vt/vt.c:1015 vesafb_probe.cold+0x1162/0x1162 respond_string+0x290/0x290 include/linux/tty_flip.h:27 fbcon_set_palette+0x3b1/0x4a0 drivers/video/fbdev/core/fbcon.c:2764 fbcon_modechanged+0x581/0x720 drivers/video/fbdev/core/fbcon.c:3000 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3047 fb_set_var+0xad0/0xd40 drivers/video/fbdev/core/fbmem.c:1056 fb_blank+0x190/0x190 drivers/video/fbdev/core/fbmem.c:1081 mark_held_locks+0xe0/0xe0 kernel/locking/lockdep.c:3620 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x62/0xe0 kernel/locking/spinlock.c:191 do_fb_ioctl+0x390/0x6e0 drivers/video/fbdev/core/fbmem.c:1109 fb_mmap+0x550/0x550 drivers/video/fbdev/core/fbmem.c:1383 tomoyo_execute_permission+0x470/0x470 security/tomoyo/file.c:168 __bfs+0x520/0x520 kernel/locking/lockdep.c:1539 rcu_read_unlock include/linux/rcupdate.h:651 [inline] __fget_files+0x30d/0x500 fs/file.c:734 __sanitizer_cov_trace_switch+0x45/0x70 kernel/kcov.c:310 ioctl_fioasync fs/ioctl.c:601 [inline] do_vfs_ioctl+0x50c/0x1360 fs/ioctl.c:704 ksys_dup3+0x3c0/0x3c0 include/linux/compiler.h:199 __do_sys_futex kernel/futex.c:3869 [inline] __se_sys_futex kernel/futex.c:3837 [inline] __x64_sys_futex+0x380/0x4f0 kernel/futex.c:3837 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 do_fb_ioctl+0x6e0/0x6e0 drivers/video/fbdev/core/fbmem.c:1169 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:771 __do_sys_ioctl fs/ioctl.c:780 [inline] __se_sys_ioctl fs/ioctl.c:778 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x463/0x620 kernel/locking/lockdep.c:3702 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45ca29 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fbaea6b0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e4ac0 RCX: 000000000045ca29 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f2 R14: 00000000004c56c8 R15: 00007fbaea6b16d4