INFO: task syz-executor.4:16004 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28296 16004 9667 0x00000004 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x316/0x380 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x414ee1 Code: cc cc cc cc cc cc cc cc cc 48 83 ec 60 48 89 6c 24 58 48 8d 6c 24 58 48 8b 54 24 70 48 8b 5c 24 68 48 89 d6 48 09 da 48 8b 7c <24> 78 48 09 fa 48 f7 c2 07 00 00 00 0f 85 a6 01 00 00 80 3d 3a 15 RSP: 002b:0000000000a6fbf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000414ee1 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000098a80f49 R09: 0000000098a80f4d R10: 0000000000a6fcd0 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000760888 R15: 000000000075bf2c INFO: task syz-executor.2:16011 blocked for more than 143 seconds. Not tainted 5.5.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28576 16011 9663 0x80004002 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x934/0x1f90 kernel/sched/core.c:4081 schedule+0xdc/0x2b0 kernel/sched/core.c:4155 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4214 __mutex_lock_common kernel/locking/mutex.c:1033 [inline] __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118 lock_fb_info include/linux/fb.h:637 [inline] fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 __fput+0x2ff/0x890 fs/file_table.c:280 ____fput+0x16/0x20 fs/file_table.c:313 task_work_run+0x145/0x1c0 kernel/task_work.c:113 exit_task_work include/linux/task_work.h:22 [inline] do_exit+0xba9/0x2f50 kernel/exit.c:801 do_group_exit+0x135/0x360 kernel/exit.c:899 get_signal+0x47c/0x24f0 kernel/signal.c:2734 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline] syscall_return_slowpath arch/x86/entry/common.c:278 [inline] do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 Code: 80 00 00 0f 83 b2 00 00 00 48 3d f8 03 00 00 77 7a 48 83 c0 07 48 c1 e8 03 48 3d 81 00 00 00 0f 83 df 00 00 00 48 8d 15 55 5c <9f> 00 0f b6 04 10 48 83 f8 43 0f 83 c0 00 00 00 48 8d 0d 80 5d 9f RSP: 002b:00007f889cd20c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: 0000000000000003 RBX: 00007f889cd216d4 RCX: 000000000045b349 RDX: 0000000000000000 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000772 R14: 00000000004c8dbe R15: 000000000075bf2c Showing all locks held in the system: 1 lock held by khungtaskd/1132: #0: ffffffff899a3dc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333 1 lock held by rsyslogd/9525: #0: ffff8880a6f83160 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/9615: #0: ffff888097ad9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019eb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9616: #0: ffff88809f2a9090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019ab2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9617: #0: ffff8880a714f090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc90001a0b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9618: #0: ffff8880a4951090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019db2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9619: #0: ffff8880a6ddd090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc900019fb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9620: #0: ffff8880a0193090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000199b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 2 locks held by getty/9621: #0: ffff88809f8c6090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340 #1: ffffc9000194b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/9808: #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 1 lock held by syz-executor.2/9809: #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 3 locks held by kworker/u4:3/12438: #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff88821b78e528 ((wq_completion)netns){+.+.}, at: process_one_work+0x88b/0x1740 kernel/workqueue.c:2235 #1: ffffc90001e47dc0 (net_cleanup_work){+.+.}, at: process_one_work+0x8c1/0x1740 kernel/workqueue.c:2239 #2: ffffffff8a4c6248 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0xaf0 net/core/net_namespace.c:559 1 lock held by syz-executor.4/16004: #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 2 locks held by syz-executor.3/16010: 1 lock held by syz-executor.2/16011: #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: lock_fb_info include/linux/fb.h:637 [inline] #0: ffff888218cda070 (&fb_info->lock){+.+.}, at: fb_release+0x55/0x150 drivers/video/fbdev/core/fbmem.c:1435 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1132 Comm: khungtaskd Not tainted 5.5.0-rc6-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+0x197/0x210 lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb11/0x10c0 kernel/hung_task.c:289 kthread+0x361/0x430 kernel/kthread.c:255 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: 16010 Comm: syz-executor.3 Not tainted 5.5.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:187 Code: 00 00 00 00 55 48 89 e5 65 48 8b 04 25 c0 1e 02 00 65 8b 15 54 29 8d 7e 81 e2 00 01 1f 00 48 8b 75 08 75 2b 8b 90 80 13 00 00 <83> fa 02 75 20 48 8b 88 88 13 00 00 8b 80 84 13 00 00 48 8b 11 48 RSP: 0018:ffffc90007a4f320 EFLAGS: 00000246 RAX: ffff88802a03c280 RBX: 0000000000000000 RCX: ffffffff83c10a60 RDX: 0000000000000002 RSI: ffffffff83c10a03 RDI: 0000000000000007 RBP: ffffc90007a4f320 R08: ffff88802a03c280 R09: 0000000000000040 R10: ffffed104320b9c3 R11: ffff88821905ce1f R12: ffff888218cda000 R13: ffff8880000a0000 R14: 00000000c6def2cc R15: 00000000c6def2cc FS: 00007fc5d64ef700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 0000000096d24000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ffs arch/x86/include/asm/bitops.h:297 [inline] cfb_fillrect+0x3f3/0x7c0 drivers/video/fbdev/core/cfbfillrect.c:325 vga16fb_fillrect+0x6ce/0x19b0 drivers/video/fbdev/vga16fb.c:951 bit_clear_margins+0x30b/0x530 drivers/video/fbdev/core/bitblit.c:232 fbcon_clear_margins+0x1e9/0x250 drivers/video/fbdev/core/fbcon.c:1372 fbcon_switch+0xd7f/0x17f0 drivers/video/fbdev/core/fbcon.c:2354 redraw_screen+0x2b6/0x7d0 drivers/tty/vt/vt.c:997 fbcon_modechanged+0x5c3/0x790 drivers/video/fbdev/core/fbcon.c:2991 fbcon_update_vcs+0x42/0x50 drivers/video/fbdev/core/fbcon.c:3038 fb_set_var+0xb32/0xdd0 drivers/video/fbdev/core/fbmem.c:1051 do_fb_ioctl+0x390/0x7d0 drivers/video/fbdev/core/fbmem.c:1104 fb_ioctl+0xe6/0x130 drivers/video/fbdev/core/fbmem.c:1180 vfs_ioctl fs/ioctl.c:47 [inline] file_ioctl fs/ioctl.c:545 [inline] do_vfs_ioctl+0x977/0x14e0 fs/ioctl.c:732 ksys_ioctl+0xab/0xd0 fs/ioctl.c:749 __do_sys_ioctl fs/ioctl.c:756 [inline] __se_sys_ioctl fs/ioctl.c:754 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:754 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b349 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:00007fc5d64eec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fc5d64ef6d4 RCX: 000000000045b349 RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000002cd R14: 00000000004c3dc6 R15: 000000000075bf2c