INFO: task syz-executor.4:12024 can't die for more than 143 seconds. syz-executor.4 D28360 12024 7278 0x00004006 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:638 [inline] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1447 __fput+0x27e/0x8e0 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 get_signal+0xd6c/0x1ee0 kernel/signal.c:2547 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline] __prepare_exit_to_usermode+0x14d/0x1f0 arch/x86/entry/common.c:269 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007f9c0db94c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 000000000000c480 RCX: 000000000045c1d9 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc2cd2eaff R14: 00007f9c0db959c0 R15: 000000000078bf0c INFO: task syz-executor.4:12024 blocked for more than 143 seconds. Not tainted 5.8.0-rc5-next-20200716-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28360 12024 7278 0x00004006 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:638 [inline] fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1447 __fput+0x27e/0x8e0 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:135 get_signal+0xd6c/0x1ee0 kernel/signal.c:2547 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline] __prepare_exit_to_usermode+0x14d/0x1f0 arch/x86/entry/common.c:269 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007f9c0db94c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: 0000000000000000 RBX: 000000000000c480 RCX: 000000000045c1d9 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffc2cd2eaff R14: 00007f9c0db959c0 R15: 000000000078bf0c INFO: task syz-executor.3:12077 can't die for more than 143 seconds. syz-executor.3 R running task 27544 12077 7137 0x00004006 Call Trace: INFO: task syz-executor.3:12125 can't die for more than 143 seconds. syz-executor.3 D28728 12125 7137 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:638 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4b9/0x11b0 fs/open.c:822 do_open fs/namei.c:3249 [inline] path_openat+0x1b97/0x2720 fs/namei.c:3366 do_filp_open+0x17e/0x3c0 fs/namei.c:3393 do_sys_openat2+0x16d/0x3e0 fs/open.c:1173 do_sys_open fs/open.c:1189 [inline] __do_sys_openat fs/open.c:1203 [inline] __se_sys_openat fs/open.c:1198 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1198 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007fd31720ec78 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: 00007ffe6be8859f R14: 00007fd31720f9c0 R15: 000000000078bfac INFO: task syz-executor.3:12125 blocked for more than 143 seconds. Not tainted 5.8.0-rc5-next-20200716-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.3 D28728 12125 7137 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:638 [inline] fb_open+0xd3/0x430 drivers/video/fbdev/core/fbmem.c:1418 chrdev_open+0x266/0x770 fs/char_dev.c:414 do_dentry_open+0x4b9/0x11b0 fs/open.c:822 do_open fs/namei.c:3249 [inline] path_openat+0x1b97/0x2720 fs/namei.c:3366 do_filp_open+0x17e/0x3c0 fs/namei.c:3393 do_sys_openat2+0x16d/0x3e0 fs/open.c:1173 do_sys_open fs/open.c:1189 [inline] __do_sys_openat fs/open.c:1203 [inline] __se_sys_openat fs/open.c:1198 [inline] __x64_sys_openat+0x13f/0x1f0 fs/open.c:1198 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007fd31720ec78 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: 00007ffe6be8859f R14: 00007fd31720f9c0 R15: 000000000078bfac Showing all locks held in the system: 1 lock held by khungtaskd/1164: #0: ffffffff89c53980 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6542: #0: ffff88809f1ea130 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930 1 lock held by syz-executor.4/12024: #0: ffff8880a3792078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:638 [inline] #0: ffff8880a3792078 (&fb_info->lock){+.+.}-{3:3}, at: fb_release+0x4e/0x140 drivers/video/fbdev/core/fbmem.c:1447 2 locks held by syz-executor.3/12077: 1 lock held by syz-executor.3/12125: #0: ffff8880a3792078 (&fb_info->lock){+.+.}-{3:3}, at: lock_fb_info include/linux/fb.h:638 [inline] #0: ffff8880a3792078 (&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: 1164 Comm: khungtaskd Not tainted 5.8.0-rc5-next-20200716-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+0x44/0xd7 lib/nmi_backtrace.c:105 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 CPU: 0 PID: 12077 Comm: syz-executor.3 Not tainted 5.8.0-rc5-next-20200716-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:write_comp_data+0x2f/0x80 kernel/kcov.c:218 Code: 05 56 d3 8d 7e 65 48 8b 34 25 c0 fe 01 00 a9 00 01 ff 00 74 0f f6 c4 01 74 59 8b 86 0c 14 00 00 85 c0 74 4f 8b 86 e8 13 00 00 <83> f8 03 75 44 48 8b 86 f0 13 00 00 8b b6 ec 13 00 00 4c 8b 00 48 RSP: 0018:ffffc90017107488 EFLAGS: 00000246 RAX: 0000000000000002 RBX: 0000000000000000 RCX: ffffffff83c42aa9 RDX: 0000000000000020 RSI: ffff888091748580 RDI: 0000000000000005 RBP: ffff8880000a0180 R08: 0000000000001400 R09: 0000000000000040 R10: 0000000000000007 R11: 0000000000000000 R12: 0000000000000050 R13: ffff8880000a0000 R14: 0000000000000000 R15: 0000000000000020 FS: 00007fd317230700(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055b7b0a30520 CR3: 000000009f0b9000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:63 [inline] bitfill_aligned+0x139/0x200 drivers/video/fbdev/core/cfbfillrect.c:35 cfb_fillrect+0x40b/0x7b0 drivers/video/fbdev/core/cfbfillrect.c:327 vga16fb_fillrect+0x683/0x193b drivers/video/fbdev/vga16fb.c:951 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_set_all_vcs+0x3b6/0x470 drivers/video/fbdev/core/fbcon.c:3039 fbcon_update_vcs+0x26/0x50 drivers/video/fbdev/core/fbcon.c:3046 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:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007fd31722fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000000c480 RCX: 000000000045c1d9 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000078bf40 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007ffe6be8859f R14: 00007fd3172309c0 R15: 000000000078bf0c