INFO: task syz-executor.1:10151 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D27952 10151 7154 0x00004004 Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4088 schedule+0x188/0x220 kernel/sched/core.c:4163 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4222 __mutex_lock_common+0x129f/0x2fc0 kernel/locking/mutex.c:1033 lock_fb_info include/linux/fb.h:637 [inline] do_fb_ioctl+0x63/0x6f0 drivers/video/fbdev/core/fbmem.c:1097 fb_write+0x540/0x540 drivers/video/fbdev/core/fbmem.c:849 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] do_fb_ioctl+0x63/0x6f0 drivers/video/fbdev/core/fbmem.c:1097 do_vfs_ioctl+0x6ea/0x1910 fs/ioctl.c:741 fb_write+0x540/0x540 drivers/video/fbdev/core/fbmem.c:849 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 INFO: task syz-executor.1:10190 blocked for more than 143 seconds. Not tainted 5.7.0-rc1-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28576 10190 7154 0x00004004 Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x805/0xc90 kernel/sched/core.c:4088 schedule+0x188/0x220 kernel/sched/core.c:4163 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4222 __mutex_lock_common+0x129f/0x2fc0 kernel/locking/mutex.c:1033 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0x14b/0x3b0 drivers/video/fbdev/core/fbmem.c:1418 __mutex_lock kernel/locking/mutex.c:1103 [inline] mutex_lock_nested+0x1a/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0x14b/0x3b0 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x498/0x580 fs/char_dev.c:414 cd_forget+0x150/0x150 include/linux/spinlock.h:393 do_dentry_open+0x82e/0x10b0 fs/open.c:797 do_open fs/namei.c:3229 [inline] path_openat+0x2790/0x38b0 fs/namei.c:3346 do_filp_open+0x191/0x3a0 fs/namei.c:3373 __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+0x566/0x600 fs/file.c:534 do_sys_openat2+0x463/0x770 fs/open.c:1148 do_sys_open fs/open.c:1164 [inline] __do_sys_openat fs/open.c:1178 [inline] __se_sys_openat fs/open.c:1173 [inline] __x64_sys_openat+0x1c8/0x1f0 fs/open.c:1173 do_syscall_64+0xf3/0x1b0 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/u4:7/389: 1 lock held by khungtaskd/1097: #0: ffffffff892e8590 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30 net/mptcp/pm_netlink.c:858 1 lock held by in:imklog/6605: #0: ffff88809ca85930 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x25d/0x2f0 fs/file.c:826 2 locks held by syz-executor.1/10143: 1 lock held by syz-executor.1/10151: #0: ffff8880a3bea078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3bea078 (&fb_info->lock){+.+.}-{3:3}, at: do_fb_ioctl+0x63/0x6f0 drivers/video/fbdev/core/fbmem.c:1097 1 lock held by syz-executor.1/10190: #0: ffff8880a3bea078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff8880a3bea078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0x14b/0x3b0 drivers/video/fbdev/core/fbmem.c:1418 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1097 Comm: khungtaskd Not tainted 5.7.0-rc1-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+0x1e9/0x30e lib/dump_stack.c:118 nmi_cpu_backtrace+0x9f/0x180 lib/nmi_backtrace.c:101 arch_trigger_cpumask_backtrace+0x10/0x10 arch/x86/kernel/apic/hw_nmi.c:38 nmi_trigger_cpumask_backtrace+0x16a/0x280 lib/nmi_backtrace.c:62 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xd2a/0xd40 kernel/hung_task.c:289 kthread+0x353/0x380 kernel/kthread.c:268 hungtask_pm_notify+0x50/0x50 kernel/hung_task.c:265 kthread_blkcg+0xd0/0xd0 kernel/kthread.c:1247 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10143 Comm: syz-executor.1 Not tainted 5.7.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x31/0x50 kernel/kcov.c:192 Code: 0c 25 40 1e 02 00 65 8b 15 68 bb 8e 7e f7 c2 00 01 1f 00 75 2c 8b 91 d8 13 00 00 83 fa 02 75 21 48 8b 91 e0 13 00 00 48 8b 32 <48> 8d 7e 01 8b 89 dc 13 00 00 48 39 cf 73 08 48 89 44 f2 08 48 89 RSP: 0018:ffffc9001a687950 EFLAGS: 00000246 RAX: ffffffff83d17b40 RBX: 0000000000000000 RCX: ffff888045b1e300 RDX: ffffc900043c9000 RSI: 000000000003ffff RDI: 0000000000040000 RBP: 0000000000000032 R08: ffffffff83d17afb R09: ffffffff83d1726f R10: ffff888045b1e300 R11: 0000000000000002 R12: 00000000e30dcd1b R13: ffff8880000a001e R14: ffffffffffffffb0 R15: 000000000000004f FS: 00007fcf83c0d700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9b0f285db8 CR3: 000000016e2f7000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: vga16fb_fillrect+0xfe0/0x13e0 drivers/video/fbdev/vga16fb.c:922 bit_clear_margins+0x37b/0x620 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins drivers/video/fbdev/core/fbcon.c:1381 [inline] fbcon_switch+0x1448/0x1e40 drivers/video/fbdev/core/fbcon.c:2363 redraw_screen+0x4fc/0x16f0 drivers/tty/vt/vt.c:1009 fbcon_modechanged+0x8d5/0xd90 drivers/video/fbdev/core/fbcon.c:3000 fb_set_var+0x822/0xcc0 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0x502/0x6f0 drivers/video/fbdev/core/fbmem.c:1109 fb_write+0x540/0x540 drivers/video/fbdev/core/fbmem.c:849 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl fs/ioctl.c:763 [inline] __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl+0xf9/0x160 fs/ioctl.c:770 do_syscall_64+0xf3/0x1b0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c889 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:00007fcf83c0cc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcf83c0d6d4 RCX: 000000000045c889 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f0 R14: 00000000004c54e4 R15: 000000000076bf0c