syzbot

INFO: task khugepaged:1156 blocked for more than 147 seconds.
      Not tainted 5.7.0-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
khugepaged      R  running task    23728  1156      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3430 [inline]
 __schedule+0x8f3/0x1fc0 kernel/sched/core.c:4156
 preempt_schedule_common+0x4a/0xc0 kernel/sched/core.c:4312
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:50
 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline]
 _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:183
 spin_unlock include/linux/spinlock.h:393 [inline]
 khugepaged_scan_pmd mm/khugepaged.c:1345 [inline]
 khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
 khugepaged_do_scan mm/khugepaged.c:2193 [inline]
 khugepaged+0x307b/0x3f80 mm/khugepaged.c:2238
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

Showing all locks held in the system:
1 lock held by khungtaskd/1145:
 #0: ffffffff899bdd80 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779
1 lock held by khugepaged/1156:
3 locks held by kworker/1:4/2687:
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: __write_once_size include/linux/compiler.h:279 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline]
 #0: ffff8880aa026d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x844/0x16a0 kernel/workqueue.c:2239