INFO: task syz-executor.4:26719 blocked for more than 143 seconds. Not tainted 5.8.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28728 26719 7227 0x00004004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873 __down_common kernel/locking/semaphore.c:220 [inline] __down+0x183/0x2a0 kernel/locking/semaphore.c:237 down+0x57/0x80 kernel/locking/semaphore.c:61 console_lock+0x25/0x80 kernel/printk/printk.c:2309 vt_ioctl+0x674/0x2670 drivers/tty/vt/vt_ioctl.c:671 tty_ioctl+0x1019/0x15f0 drivers/tty/tty_io.c:2656 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:359 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cb29 Code: Bad RIP value. RSP: 002b:00007f57bfa18c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00000000004ef8e0 RCX: 000000000045cb29 RDX: 0000000020000000 RSI: 0000000000005600 RDI: 0000000000000003 RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000058a R14: 00000000004c8529 R15: 00007f57bfa196d4 Showing all locks held in the system: 5 locks held by systemd/1: 1 lock held by khungtaskd/1147: #0: ffffffff89bc1140 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 1 lock held by in:imklog/6494: #0: ffff88809ca830f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 2 locks held by agetty/6742: #0: ffff8880a6f5c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267 #1: ffffc90000fd02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156 2 locks held by kworker/u4:3/10074: 1 lock held by syz-executor.2/11674: ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1147 Comm: khungtaskd Not tainted 5.8.0-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+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 11674 Comm: syz-executor.2 Not tainted 5.8.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:preempt_count_add+0x32/0x140 kernel/sched/core.c:3873 Code: 48 ba 00 00 00 00 00 fc ff df 48 89 c1 53 83 e0 07 89 fb 48 c1 e9 03 83 c0 03 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 e1 00 00 00 <8b> 15 18 4b 41 0b 65 01 1d 31 78 b2 7e 85 d2 75 11 65 8b 05 26 78 RSP: 0000:ffffc900055a7d58 EFLAGS: 00000297 RAX: 0000000000000003 RBX: 0000000000000001 RCX: 1ffffffff1921a34 RDX: 0000000000000004 RSI: ffffffff812a7fc9 RDI: 0000000000000001 RBP: ffff8880469e3940 R08: ffffc900055a7fe0 R09: ffffc900055a7fd8 R10: ffffc900055a7ff8 R11: ffffc900055a7fe8 R12: 0000000000000000 R13: ffffc900055a7fb8 R14: 0000000000000000 R15: 00007fc6a69a24b8 FS: 00007fc6a69a3700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000038579410 CR3: 0000000090afb000 CR4: 00000000001426e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: fpregs_lock arch/x86/include/asm/fpu/api.h:35 [inline] fpu__clear+0x33/0x150 arch/x86/kernel/fpu/core.c:326 handle_signal arch/x86/kernel/signal.c:761 [inline] do_signal+0x14f4/0x2520 arch/x86/kernel/signal.c:812 exit_to_usermode_loop arch/x86/entry/common.c:212 [inline] __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:246 prepare_exit_to_usermode+0x5/0x30 arch/x86/entry/common.c:277 exc_page_fault+0xc5/0x170 arch/x86/mm/fault.c:1421 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:565 RIP: 0033:0x402660 Code: Bad RIP value. RSP: 002b:00007fc6a69a24b8 EFLAGS: 00000206 RAX: 0000000000000000 RBX: 000000000050a4a0 RCX: 0000000000416987 RDX: 00007fc6a69a24c0 RSI: 00007fc6a69a25f0 RDI: 000000000000000b RBP: 000000000078bf00 R08: 00007fc6a69a2a70 R09: 000000000078bf00 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000c39 R14: 00000000004ce8d8 R15: 00007fc6a69a36d4