audit: type=1804 audit(1594897261.223:260): pid=17503 uid=0 auid=0 ses=4 subj=system_u:system_r:kernel_t:s0 op="invalid_pcr" cause="ToMToU" comm="syz-executor.3" name="/root/syzkaller-testdir265369960/syzkaller.ZTVHmD/338/bus" dev="sda1" ino=16873 res=1 netlink: 41539 bytes leftover after parsing attributes in process `syz-executor.4'. NOHZ: local_softirq_pending 08 NOHZ: local_softirq_pending 08 INFO: task syz-executor.0:17511 blocked for more than 140 seconds. Not tainted 4.14.184-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29472 17511 6351 0x00000004 Call Trace: context_switch kernel/sched/core.c:2808 [inline] __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384 schedule+0x8d/0x1b0 kernel/sched/core.c:3428 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3486 __mutex_lock_common kernel/locking/mutex.c:833 [inline] __mutex_lock+0x5f0/0x1430 kernel/locking/mutex.c:893 fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468 chrdev_open+0x1fc/0x540 fs/char_dev.c:423 do_dentry_open+0x44b/0xec0 fs/open.c:777 vfs_open+0x105/0x220 fs/open.c:888 do_last fs/namei.c:3428 [inline] path_openat+0xb68/0x2aa0 fs/namei.c:3569 do_filp_open+0x18e/0x250 fs/namei.c:3603 do_sys_open+0x292/0x3e0 fs/open.c:1081 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007f09d44b4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 000000000001fe40 RCX: 000000000045c1d9 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000078bfe8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bfac R13: 00007ffc30db251f R14: 00007f09d44b59c0 R15: 000000000078bfac Showing all locks held in the system: 1 lock held by khungtaskd/1056: #0: (tasklist_lock){.+.+}, at: [] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548 1 lock held by in:imklog/5964: #0: (&f->f_pos_lock){+.+.}, at: [] __fdget_pos+0xa6/0xc0 fs/file.c:769 1 lock held by syz-executor.0/17511: #0: (&fb_info->lock){+.+.}, at: [] fb_open+0xb7/0x400 drivers/video/fbdev/core/fbmem.c:1468 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1056 Comm: khungtaskd Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x1b2/0x283 lib/dump_stack.c:58 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline] watchdog+0x5e2/0xb80 kernel/hung_task.c:274 kthread+0x30d/0x420 kernel/kthread.c:232 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 17507 Comm: syz-executor.0 Not tainted 4.14.184-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 task: ffff88808490a440 task.stack: ffff88808ea48000 RIP: 0010:__read_once_size include/linux/compiler.h:183 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x1d/0x50 kernel/kcov.c:67 RSP: 0018:ffff88808ea4f3d8 EFLAGS: 00000246 RAX: ffff88808490a440 RBX: ffff8880000a0050 RCX: ffffc90005afc000 RDX: 0000000000000000 RSI: ffffffff831f9ef3 RDI: ffff88808ea4f490 RBP: 0000000000000050 R08: 000000000000ffff R09: ffffed104323cf8c R10: ffffed104323cf8b R11: ffff8882191e7c5f R12: ffff8880000a000d R13: 0000000000000000 R14: 00000000e716b18b R15: 000000000000004f FS: 00007f09d44d6700(0000) GS:ffff8880aed00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00a738000 CR3: 000000008785b000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: writeb arch/x86/include/asm/io.h:65 [inline] vga16fb_fillrect+0x943/0x1880 drivers/video/fbdev/vga16fb.c:923 bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x274/0x300 drivers/video/fbdev/core/fbcon.c:1320 fbcon_switch+0xc4e/0x1700 drivers/video/fbdev/core/fbcon.c:2302 redraw_screen+0x332/0x760 drivers/tty/vt/vt.c:689 fbcon_modechanged+0x552/0x800 drivers/video/fbdev/core/fbcon.c:2949 fbcon_event_notify+0x11a/0x1750 drivers/video/fbdev/core/fbcon.c:3302 notifier_call_chain+0x107/0x1a0 kernel/notifier.c:93 __blocking_notifier_call_chain kernel/notifier.c:317 [inline] __blocking_notifier_call_chain kernel/notifier.c:304 [inline] blocking_notifier_call_chain kernel/notifier.c:328 [inline] blocking_notifier_call_chain+0x79/0x90 kernel/notifier.c:325 fb_set_var+0xaad/0xc70 drivers/video/fbdev/core/fbmem.c:1054 do_fb_ioctl+0x3cc/0x840 drivers/video/fbdev/core/fbmem.c:1127 fb_ioctl+0xda/0x120 drivers/video/fbdev/core/fbmem.c:1242 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x45c1d9 RSP: 002b:00007f09d44d5c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000c480 RCX: 000000000045c1d9 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc30db251f R14: 00007f09d44d69c0 R15: 000000000078bf0c Code: 26 f2 dd 08 00 00 00 00 e9 be ed ff ff 90 65 48 8b 04 25 40 ee 01 00 48 85 c0 74 1a 65 8b 15 db 47 a7 7e 81 e2 00 01 1f 00 75 0b <8b> 90 58 13 00 00 83 fa 01 74 01 c3 48 8b 34 24 48 8b 88 60 13