INFO: task syz-executor.5:8619 can't die for more than 143 seconds. syz-executor.5 R running task 27440 8619 7327 0x00004006 Call Trace: context_switch kernel/sched/core.c:3445 [inline] __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169 preempt_schedule_irq+0xb0/0x150 kernel/sched/core.c:4427 idtentry_exit_cond_resched arch/x86/entry/common.c:645 [inline] idtentry_exit_cond_rcu+0xc0/0xf0 arch/x86/entry/common.c:692 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:596 RIP: 0010:writeb arch/x86/include/asm/io.h:65 [inline] RIP: 0010:vga16fb_fillrect+0x9bb/0x193b drivers/video/fbdev/vga16fb.c:923 Code: ff ff e8 a8 b8 ab fd 48 63 44 24 10 45 31 f6 48 89 04 24 e8 97 b8 ab fd 31 ff 89 de 31 ed e8 0c b5 ab fd 85 db 4d 89 ec 74 22 80 b8 ab fd 45 88 34 24 83 c5 01 89 df 49 83 c4 01 89 ee e8 6c RSP: 0018:ffffc900044a75b0 EFLAGS: 00000216 RAX: 0000000000000002 RBX: 0000000000000050 RCX: ffffffff83c84e94 RDX: 0000000000000008 RSI: ffff888048c945c0 RDI: 0000000000000004 RBP: 0000000000000008 R08: 0000000000000001 R09: ffff88821894005f R10: 0000000000000050 R11: 0000000000000000 R12: ffff8880000a0008 R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000fafe040f bit_clear_margins+0x2d5/0x4a0 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1d5/0x230 drivers/video/fbdev/core/fbcon.c:1381 fbcon_switch+0xb6f/0x16c0 drivers/video/fbdev/core/fbcon.c:2363 redraw_screen+0x2af/0x770 drivers/tty/vt/vt.c:1020 fbcon_modechanged+0x575/0x710 drivers/video/fbdev/core/fbcon.c:3001 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3048 fb_set_var+0xae8/0xd60 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0x33f/0x6c0 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f6318fd3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e55e0 RCX: 000000000045cb29 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000005 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002fd R14: 00000000004c58a5 R15: 00007f6318fd46d4 INFO: task syz-executor.5:8640 can't die for more than 143 seconds. syz-executor.5 D29696 8640 7327 0x00000004 Call Trace: context_switch kernel/sched/core.c:3445 [inline] __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169 schedule+0xd0/0x2a0 kernel/sched/core.c:4244 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4303 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_set_user_cmap+0x33d/0x450 drivers/video/fbdev/core/fbcmap.c:288 do_fb_ioctl+0x66e/0x6c0 drivers/video/fbdev/core/fbmem.c:1128 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f6318fb2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e5560 RCX: 000000000045cb29 RDX: 0000000020000280 RSI: 0000000000004605 RDI: 0000000000000005 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002fb R14: 00000000004c587b R15: 00007f6318fb36d4 INFO: task syz-executor.5:8640 blocked for more than 143 seconds. Not tainted 5.8.0-rc3-next-20200703-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D29696 8640 7327 0x00000004 Call Trace: context_switch kernel/sched/core.c:3445 [inline] __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169 schedule+0xd0/0x2a0 kernel/sched/core.c:4244 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4303 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_set_user_cmap+0x33d/0x450 drivers/video/fbdev/core/fbcmap.c:288 do_fb_ioctl+0x66e/0x6c0 drivers/video/fbdev/core/fbmem.c:1128 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f6318fb2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e5560 RCX: 000000000045cb29 RDX: 0000000020000280 RSI: 0000000000004605 RDI: 0000000000000005 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002fb R14: 00000000004c587b R15: 00007f6318fb36d4 INFO: task syz-executor.5:8655 can't die for more than 143 seconds. syz-executor.5 D28800 8655 7327 0x00004004 Call Trace: context_switch kernel/sched/core.c:3445 [inline] __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169 schedule+0xd0/0x2a0 kernel/sched/core.c:4244 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4303 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] do_fb_ioctl+0x15e/0x6c0 drivers/video/fbdev/core/fbmem.c:1168 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f6318f91c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e6060 RCX: 000000000045cb29 RDX: 00000000200000c0 RSI: 00000000401c5820 RDI: 0000000000000005 RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000327 R14: 00000000004c5c11 R15: 00007f6318f926d4 INFO: task syz-executor.5:8655 blocked for more than 143 seconds. Not tainted 5.8.0-rc3-next-20200703-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28800 8655 7327 0x00004004 Call Trace: context_switch kernel/sched/core.c:3445 [inline] __schedule+0x8b4/0x1e80 kernel/sched/core.c:4169 schedule+0xd0/0x2a0 kernel/sched/core.c:4244 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4303 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x3e2/0x10d0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] do_fb_ioctl+0x15e/0x6c0 drivers/video/fbdev/core/fbmem.c:1168 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f6318f91c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e6060 RCX: 000000000045cb29 RDX: 00000000200000c0 RSI: 00000000401c5820 RDI: 0000000000000005 RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000327 R14: 00000000004c5c11 R15: 00007f6318f926d4 Showing all locks held in the system: 1 lock held by khungtaskd/1155: #0: ffffffff89bc3040 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6557: #0: ffff8880a2f95df0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:928 2 locks held by syz-executor.5/8619: 1 lock held by syz-executor.5/8640: #0: ffff88821893f078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff88821893f078 (&fb_info->lock){+.+.}-{3:3}, at: fb_set_user_cmap+0x33d/0x450 drivers/video/fbdev/core/fbcmap.c:288 1 lock held by syz-executor.5/8655: #0: ffff88821893f078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff88821893f078 (&fb_info->lock){+.+.}-{3:3}, at: do_fb_ioctl+0x15e/0x6c0 drivers/video/fbdev/core/fbmem.c:1168 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1155 Comm: khungtaskd Not tainted 5.8.0-rc3-next-20200703-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:147 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd89/0xf30 kernel/hung_task.c:339 kthread+0x3b5/0x4a0 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60