INFO: task syz-executor.0:14573 blocked for more than 143 seconds. Not tainted 5.5.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28408 14573 8758 0x00004004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x87f/0xcd0 kernel/sched/core.c:4081 schedule+0x188/0x210 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common+0x11f1/0x2f30 kernel/locking/mutex.c:1033 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x4d/0x1a0 drivers/video/fbdev/core/fbmem.c:1435 __fput+0x2e4/0x740 fs/file_table.c:280 ____fput+0x15/0x20 fs/file_table.c:313 task_work_run+0x176/0x1b0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop arch/x86/entry/common.c:164 [inline] prepare_exit_to_usermode+0x480/0x5b0 arch/x86/entry/common.c:195 syscall_return_slowpath+0x113/0x4a0 arch/x86/entry/common.c:278 do_syscall_64+0x11f/0x1c0 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414ee1 Code: cc cc cc cc cc cc cc cc cc 48 83 ec 60 48 89 6c 24 58 48 8d 6c 24 58 48 8b 54 24 70 48 8b 5c 24 68 48 89 d6 48 09 da 48 8b 7c <24> 78 48 09 fa 48 f7 c2 07 00 00 00 0f 85 a6 01 00 00 80 3d fa 15 RSP: 002b:00007ffe9d8ab300 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000414ee1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: 000000007d6e43d0 R09: 000000007d6e43d4 R10: 00007ffe9d8ab3e0 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000760ff0 R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1116: #0: ffffffff890d45c0 (rcu_read_lock){....}, at: rcu_lock_acquire+0x4/0x30 include/linux/rcupdate.h:207 1 lock held by rsyslogd/8629: #0: ffff8880a27ff1a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x243/0x2e0 fs/file.c:801 2 locks held by getty/8719: #0: ffff8880a2810090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8720: #0: ffff8880986eb090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8721: #0: ffff8880a71e8090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019bb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8722: #0: ffff88809f6e8090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8723: #0: ffff8880a4b48090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900017cb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8724: #0: ffff88809e4b7090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc900019eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 2 locks held by getty/8725: #0: ffff88809f8f2090 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:267 #1: ffffc9000178b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x22f/0x1bc0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.0/14573: #0: ffff888218fb5070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218fb5070 (&fb_info->lock){+.+.}, at: fb_release+0x4d/0x1a0 drivers/video/fbdev/core/fbmem.c:1435 2 locks held by syz-executor.3/14587: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1116 Comm: khungtaskd Not tainted 5.5.0-rc7-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+0x1fb/0x318 lib/dump_stack.c:118 nmi_cpu_backtrace+0xaa/0x190 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x16f/0x290 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x10/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace+0x17/0x20 include/linux/nmi.h:146 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd40/0xd60 kernel/hung_task.c:289 kthread+0x332/0x350 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: 14587 Comm: syz-executor.3 Not tainted 5.5.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x35/0x50 kernel/kcov.c:192 Code: 0c 25 c0 1d 02 00 65 8b 15 34 a0 8b 7e f7 c2 00 01 1f 00 75 2c 8b 91 80 13 00 00 83 fa 02 75 21 48 8b 91 88 13 00 00 48 8b 32 <48> 8d 7e 01 8b 89 84 13 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 RSP: 0018:ffffc90001c97320 EFLAGS: 00000246 RAX: ffffffff83ca18a3 RBX: 0000000000000005 RCX: ffff8880a281e2c0 RDX: ffffc90010d8a000 RSI: 000000000003ffff RDI: 0000000000000000 RBP: ffffc90001c97320 R08: ffffffff83ca1887 R09: 0000000000000040 R10: ffff8880a281e2c0 R11: 0000000000000002 R12: ffff8880000a0008 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffffffffffff FS: 00007f5af3dd9700(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007faf53ff6a06 CR3: 000000008b63c000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bitfill_aligned+0x1b3/0x200 drivers/video/fbdev/core/cfbfillrect.c:74 cfb_fillrect+0x57b/0x7a0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x642/0x1470 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x368/0x620 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins drivers/video/fbdev/core/fbcon.c:1372 [inline] fbcon_switch+0x1504/0x1f10 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x56e/0x1830 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x810/0xdf0 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x31/0x40 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0x8f5/0xdc0 drivers/video/fbdev/core/fbmem.c:1051 fbcon_switch+0x8e3/0x1f10 drivers/video/fbdev/core/fbcon.c:2287 redraw_screen+0x56e/0x1830 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x810/0xdf0 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x31/0x40 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0x8f5/0xdc0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x55e/0x780 drivers/video/fbdev/core/fbmem.c:1104 fb_ioctl+0xb9/0xf0 drivers/video/fbdev/core/fbmem.c:1180 do_vfs_ioctl+0x6e2/0x19b0 fs/ioctl.c:47 ksys_ioctl fs/ioctl.c:749 [inline] __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0xe3/0x120 fs/ioctl.c:754 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 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:00007f5af3dd8c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f5af3dd96d4 RCX: 000000000045b349 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 000000000000000a RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002cd R14: 00000000004c3dc6 R15: 000000000075bfd4