INFO: task syz-executor.4:13680 blocked for more than 143 seconds. Not tainted 5.7.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28672 13680 7397 0x80004002 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4217 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1447 __fput+0x33e/0x880 fs/file_table.c:280 task_work_run+0xf4/0x1b0 kernel/task_work.c:123 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xb34/0x2dd0 kernel/exit.c:796 do_group_exit+0x125/0x340 kernel/exit.c:894 get_signal+0x47b/0x24e0 kernel/signal.c:2739 do_signal+0x81/0x2240 arch/x86/kernel/signal.c:784 exit_to_usermode_loop+0x26c/0x360 arch/x86/entry/common.c:161 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline] syscall_return_slowpath arch/x86/entry/common.c:279 [inline] do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 08 0f 57 c0 0f 11 44 24 48 48 8b 4c 24 30 48 89 4c 24 48 48 89 44 24 50 48 8b 4c 24 48 48 8b 54 24 78 48 39 c2 74 12 c6 84 24 <90> 00 00 00 00 48 8b 6c 24 58 48 83 c4 60 c3 48 8b 44 24 70 48 89 RSP: 002b:00007f1f0ab41cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 000000000078bfa8 RCX: 000000000045c829 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 000000000078bfac RBP: 000000000078bfa0 R08: 0000000000000009 R09: 0000000000000000 R10: ffffffffffffffff R11: 0000000000000246 R12: 000000000078bfac R13: 00007ffe3f633b8f R14: 00007f1f0ab429c0 R15: 000000000078bfac INFO: task syz-executor.0:13705 blocked for more than 143 seconds. Not tainted 5.7.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D26328 13705 7047 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4217 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 do_dentry_open+0x4ba/0x1290 fs/open.c:797 do_open fs/namei.c:3229 [inline] path_openat+0x1e59/0x27d0 fs/namei.c:3346 do_filp_open+0x192/0x260 fs/namei.c:3373 do_sys_openat2+0x585/0x7d0 fs/open.c:1148 do_sys_open+0xc3/0x140 fs/open.c:1164 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 08 0f 57 c0 0f 11 44 24 48 48 8b 4c 24 30 48 89 4c 24 48 48 89 44 24 50 48 8b 4c 24 48 48 8b 54 24 78 48 39 c2 74 12 c6 84 24 <90> 00 00 00 00 48 8b 6c 24 58 48 83 c4 60 c3 48 8b 44 24 70 48 89 RSP: 002b:00007f4887d33c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004f7140 RCX: 000000000045c829 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000079a R14: 00000000004ca4cf R15: 00007f4887d346d4 INFO: task syz-executor.1:13683 blocked for more than 143 seconds. Not tainted 5.7.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D28400 13683 7185 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4158 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4217 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 lock_fb_info include/linux/fb.h:637 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x219/0x5c0 fs/char_dev.c:414 do_dentry_open+0x4ba/0x1290 fs/open.c:797 do_open fs/namei.c:3229 [inline] path_openat+0x1e59/0x27d0 fs/namei.c:3346 do_filp_open+0x192/0x260 fs/namei.c:3373 do_sys_openat2+0x585/0x7d0 fs/open.c:1148 do_sys_open+0xc3/0x140 fs/open.c:1164 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 08 0f 57 c0 0f 11 44 24 48 48 8b 4c 24 30 48 89 4c 24 48 48 89 44 24 50 48 8b 4c 24 48 48 8b 54 24 78 48 39 c2 74 12 c6 84 24 <90> 00 00 00 00 48 8b 6c 24 58 48 83 c4 60 c3 48 8b 44 24 70 48 89 RSP: 002b:00007fa01bdb2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00000000004f7140 RCX: 000000000045c829 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000079a R14: 00000000004ca4cf R15: 00007fa01bdb36d4 Showing all locks held in the system: 1 lock held by khungtaskd/1139: #0: ffffffff899beb00 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754 1 lock held by in:imklog/6718: #0: ffff8880a8e4cdb0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 1 lock held by syz-executor.4/13680: #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1447 2 locks held by syz-executor.0/13679: 1 lock held by syz-executor.0/13705: #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.1/13683: #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.4/13951: #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 1 lock held by syz-executor.4/13952: #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218ef6078 (&fb_info->lock){+.+.}-{3:3}, at: fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1139 Comm: khungtaskd Not tainted 5.7.0-rc3-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x388/0x470 kernel/kthread.c:268 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: 13679 Comm: syz-executor.0 Not tainted 5.7.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x16/0x50 kernel/kcov.c:183 Code: f0 13 00 00 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 65 48 8b 04 25 00 1f 02 00 65 8b 15 18 f0 8e 7e 81 e2 00 01 1f 00 <48> 8b 34 24 75 2b 8b 90 d8 13 00 00 83 fa 02 75 20 48 8b 88 e0 13 RSP: 0018:ffffc90015d5f590 EFLAGS: 00000246 RAX: ffff888048bdc300 RBX: 0000000000000050 RCX: ffffffff83c36cca RDX: 0000000000000000 RSI: 0000000000000050 RDI: 0000000000000004 RBP: 000000000000001e R08: ffff888048bdc300 R09: ffffed10431dafbc R10: ffff888218ed7ddf R11: ffffed10431dafbb R12: ffff8880000a001e R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000f11532c8 FS: 00007f4887d55700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c00013bc80 CR3: 00000000a8657000 CR4: 00000000001406f0 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+0x9c6/0x1960 drivers/video/fbdev/vga16fb.c:923 bit_clear_margins+0x2d5/0x4a0 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1de/0x240 drivers/video/fbdev/core/fbcon.c:1381 fbcon_switch+0xd21/0x1740 drivers/video/fbdev/core/fbcon.c:2363 redraw_screen+0x2ae/0x770 drivers/tty/vt/vt.c:1010 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:3000 fbcon_update_vcs+0x3a/0x50 drivers/video/fbdev/core/fbcon.c:3047 fb_set_var+0xad0/0xd40 drivers/video/fbdev/core/fbmem.c:1056 do_fb_ioctl+0x390/0x6e0 drivers/video/fbdev/core/fbmem.c:1109 fb_ioctl+0xdd/0x130 drivers/video/fbdev/core/fbmem.c:1185 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x45c829 Code: 0d b7 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f4887d54c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004e46c0 RCX: 000000000045c829 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000004 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002f0 R14: 00000000004c5497 R15: 00007f4887d556d4