INFO: task iou-sqp-17051:17056 blocked for more than 143 seconds. Not tainted 5.12.0-rc7-next-20210415-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:iou-sqp-17051 state:D stack:29688 pid:17056 ppid: 8467 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:4329 [inline] __schedule+0x917/0x2170 kernel/sched/core.c:5079 schedule+0xcf/0x270 kernel/sched/core.c:5158 __io_uring_cancel+0x285/0x420 fs/io_uring.c:8977 io_uring_files_cancel include/linux/io_uring.h:16 [inline] do_exit+0x299/0x2a70 kernel/exit.c:780 io_sq_thread+0x60a/0x1340 fs/io_uring.c:6873 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 Showing all locks held in the system: 1 lock held by khungtaskd/1654: #0: ffffffff8bf76560 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6333 1 lock held by in:imklog/8149: #0: ffff88801de360f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:990 2 locks held by login/8314: #0: ffff88801d72c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:266 #1: ffff88801d72c130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:967 [inline] #1: ffff88801d72c130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: do_tty_write drivers/tty/tty_io.c:990 [inline] #1: ffff88801d72c130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x29f/0x910 drivers/tty/tty_io.c:1133 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1654 Comm: khungtaskd Not tainted 5.12.0-rc7-next-20210415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:253 [inline] watchdog+0xd3b/0xf50 kernel/hung_task.c:338 kthread+0x3b1/0x4a0 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: 8150 Comm: rs:main Q:Reg Not tainted 5.12.0-rc7-next-20210415-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:check_preemption_disabled+0x31/0x150 lib/smp_processor_id.c:16 Code: 41 54 55 48 89 fd 53 0f 1f 44 00 00 65 44 8b 25 4d 38 f0 76 65 8b 1d 9e 92 f0 76 81 e3 ff ff ff 7f 31 ff 89 de 0f 1f 44 00 00 <85> db 74 11 0f 1f 44 00 00 44 89 e0 5b 5d 41 5c 41 5d 41 5e c3 0f RSP: 0018:ffffc9000c0875c0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff89c2cb80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff896ba760 R14: 00000000ffffffff R15: ffff8880273026c8 FS: 00007fc00d870700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6e90c67020 CR3: 00000000250d0000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:438 [inline] lock_is_held_type+0xd5/0x140 kernel/locking/lockdep.c:5556 lock_is_held include/linux/lockdep.h:283 [inline] ___might_sleep+0x3a/0x2c0 kernel/sched/core.c:8301 prepare_alloc_pages+0x3da/0x580 mm/page_alloc.c:4992 __alloc_pages+0x12f/0x500 mm/page_alloc.c:5189 alloc_pages+0x18c/0x2a0 mm/mempolicy.c:2272 __page_cache_alloc mm/filemap.c:1005 [inline] __page_cache_alloc+0x303/0x3a0 mm/filemap.c:990 pagecache_get_page+0x36e/0x1900 mm/filemap.c:1883 grab_cache_page_write_begin+0x64/0x90 mm/filemap.c:3601 ext4_da_write_begin+0x35c/0x1170 fs/ext4/inode.c:2984 generic_perform_write+0x20a/0x4f0 mm/filemap.c:3651 ext4_buffered_write_iter+0x244/0x4d0 fs/ext4/file.c:269 ext4_file_write_iter+0x423/0x14e0 fs/ext4/file.c:663 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write+0x426/0x650 fs/read_write.c:518 vfs_write+0x75a/0xa40 fs/read_write.c:605 ksys_write+0x12d/0x250 fs/read_write.c:658 do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fc0102b41cd Code: c2 20 00 00 75 10 b8 01 00 00 00 0f 05 48 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ae fc ff ff 48 89 04 24 b8 01 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 f7 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01 RSP: 002b:00007fc00d86f590 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc004026c50 RCX: 00007fc0102b41cd RDX: 000000000000047a RSI: 00007fc004026c50 RDI: 000000000000000a RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 00007fc0040269d0 R13: 00007fc00d86f5b0 R14: 000056080cc147c0 R15: 000000000000047a