INFO: task agetty:22272 blocked for more than 143 seconds. Not tainted 5.15.0-rc6-next-20211021-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:agetty state:D stack:27784 pid:22272 ppid: 1 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4965 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6246 schedule+0xd2/0x260 kernel/sched/core.c:6319 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6378 __mutex_lock_common kernel/locking/mutex.c:680 [inline] __mutex_lock+0xa32/0x12f0 kernel/locking/mutex.c:740 tiocsti drivers/tty/tty_io.c:2308 [inline] tty_ioctl+0x89f/0x1670 drivers/tty/tty_io.c:2719 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f5811554017 RSP: 002b:00007ffeb7b7fef8 EFLAGS: 00000206 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffeb7b80148 RCX: 00007f5811554017 RDX: 00007ffeb7b80147 RSI: 0000000000005412 RDI: 0000000000000000 RBP: 00007ffeb7b80180 R08: ffffffffffffff98 R09: 00007ffeb7b7ff70 R10: 0000000000000000 R11: 0000000000000206 R12: 00007ffeb7b7ff14 R13: 00007ffeb7b80070 R14: 00007ffeb7b7ff70 R15: 0000000000000000 INFO: task syz-executor.2:24117 can't die for more than 143 seconds. task:syz-executor.2 state:R running task stack:26448 pid:24117 ppid: 17086 flags:0x00004006 Call Trace: Showing all locks held in the system: 1 lock held by khungtaskd/27: #0: ffffffff8bb833a0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6458 1 lock held by in:imklog/6248: #0: ffff888072cd65f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 2 locks held by kworker/u4:8/31413: 2 locks held by agetty/22272: #0: ffff888079865098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:252 #1: ffff888010c790b8 (&buf->lock){+.+.}-{3:3}, at: tiocsti drivers/tty/tty_io.c:2308 [inline] #1: ffff888010c790b8 (&buf->lock){+.+.}-{3:3}, at: tty_ioctl+0x89f/0x1670 drivers/tty/tty_io.c:2719 6 locks held by syz-executor.2/24117: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.0-rc6-next-20211021-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:254 [inline] watchdog+0xcb7/0xed0 kernel/hung_task.c:339 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 24117 Comm: syz-executor.2 Not tainted 5.15.0-rc6-next-20211021-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:slow_down_io arch/x86/include/asm/paravirt.h:55 [inline] RIP: 0010:outb_p arch/x86/include/asm/io.h:334 [inline] RIP: 0010:vga_io_w include/video/vga.h:209 [inline] RIP: 0010:vga_io_rgfx include/video/vga.h:388 [inline] RIP: 0010:setsr drivers/video/fbdev/vga16fb.c:160 [inline] RIP: 0010:vga_8planes_imageblit drivers/video/fbdev/vga16fb.c:1142 [inline] RIP: 0010:vga_imageblit_expand drivers/video/fbdev/vga16fb.c:1203 [inline] RIP: 0010:vga16fb_imageblit+0x1cd3/0x2aa0 drivers/video/fbdev/vga16fb.c:1260 Code: 85 e5 06 00 00 48 83 3d 7a ea 79 07 00 0f 84 b0 05 00 00 e8 cf ed 51 fd e8 3a d1 0d fd 66 90 b8 01 00 00 00 ba ce 03 00 00 ee <48> b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 80 3c 02 00 0f RSP: 0018:ffffc9000b71f0f8 EFLAGS: 00000246 RAX: 0000000000000001 RBX: ffffffff8b9f7560 RCX: ffffc9000f541000 RDX: 00000000000003ce RSI: ffffffff84258af1 RDI: 0000000000000003 RBP: ffffc9000b71f288 R08: 0000000000000001 R09: 0000000000000001 R10: ffffffff84258aa5 R11: 0000000000000001 R12: dffffc0000000000 R13: ffff8880000a09e0 R14: 0000000000000001 R15: ffff888017f3c000 FS: 00007f4e003e8700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb8ab005000 CR3: 0000000087cf5000 CR4: 00000000003506f0 Call Trace: bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:124 [inline] bit_putcs+0x6e1/0xd20 drivers/video/fbdev/core/bitblit.c:173 fbcon_putcs+0x353/0x440 drivers/video/fbdev/core/fbcon.c:1277 fbcon_redraw.constprop.0+0x41a/0x4b0 drivers/video/fbdev/core/fbcon.c:1435 fbcon_scroll+0x45c/0x610 drivers/video/fbdev/core/fbcon.c:1469 con_scroll+0x5b9/0x6d0 drivers/tty/vt/vt.c:630 lf+0x26b/0x2c0 drivers/tty/vt/vt.c:1507 vc_con_write_normal drivers/tty/vt/vt.c:2851 [inline] do_con_write+0xf1c/0x1e40 drivers/tty/vt/vt.c:2955 con_put_char+0x70/0xa0 drivers/tty/vt/vt.c:3303 tty_put_char+0xb7/0x150 drivers/tty/tty_io.c:3173 __process_echoes+0x583/0x9f0 drivers/tty/n_tty.c:726 commit_echoes+0x148/0x210 drivers/tty/n_tty.c:791 n_tty_receive_char+0x3b0/0x5b0 drivers/tty/n_tty.c:1411 n_tty_receive_buf_standard drivers/tty/n_tty.c:1560 [inline] __receive_buf drivers/tty/n_tty.c:1577 [inline] n_tty_receive_buf_common+0x109e/0x4780 drivers/tty/n_tty.c:1674 tty_ldisc_receive_buf+0xa3/0x190 drivers/tty/tty_buffer.c:471 paste_selection+0x1de/0x4c0 drivers/tty/vt/selection.c:408 tioclinux+0x126/0x560 drivers/tty/vt/vt.c:3204 vt_ioctl+0x229a/0x2b10 drivers/tty/vt/vt_ioctl.c:762 tty_ioctl+0xbbd/0x1670 drivers/tty/tty_io.c:2805 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:874 [inline] __se_sys_ioctl fs/ioctl.c:860 [inline] __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f4e02e72a39 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4e003e8188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4e02f75f60 RCX: 00007f4e02e72a39 RDX: 00000000200000c0 RSI: 000000000000541c RDI: 0000000000000006 RBP: 00007f4e02ecce8f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc26e1ba0f R14: 00007f4e003e8300 R15: 0000000000022000 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e5 06 in $0x6,%eax 2: 00 00 add %al,(%rax) 4: 48 83 3d 7a ea 79 07 cmpq $0x0,0x779ea7a(%rip) # 0x779ea86 b: 00 c: 0f 84 b0 05 00 00 je 0x5c2 12: e8 cf ed 51 fd callq 0xfd51ede6 17: e8 3a d1 0d fd callq 0xfd0dd156 1c: 66 90 xchg %ax,%ax 1e: b8 01 00 00 00 mov $0x1,%eax 23: ba ce 03 00 00 mov $0x3ce,%edx 28: ee out %al,(%dx) * 29: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax <-- trapping instruction 30: fc ff df 33: 48 89 da mov %rbx,%rdx 36: 48 c1 ea 03 shr $0x3,%rdx 3a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) 3e: 0f .byte 0xf