syzbot

hrtimer: interrupt took 62263 ns
sched: RT throttling activated for rt_rq 00000000ddd2b4a1 (cpu 0)
potential CPU hogs:
	syz-executor.3 (2987)
INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 0, t=10502 jiffies, g=570, c=569, q=90)
All QSes seen, last rcu_preempt kthread activity 10499 (4294964452-4294953953), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.2  R  running task    26504  3212   2112 0x00000000
 ffff8801db607cc8 ffffffff813fcbf1 ffffffff813fc9f0 0000000000002903
 00000000ffffcbe1 00000000fffff4e4 dffffc0000000000 ffff8801db621c80
 ffffffff830d5980 ffff8801db607d98 ffffffff81408e6c 0000000000000000
Call Trace:
 <IRQ> [  272.854926]  [<0000000089bc4351>] sched_show_task.cold+0x27f/0x327 kernel/sched/core.c:5312
 [<000000000ca14c79>] print_other_cpu_stall kernel/rcu/tree.c:1403 [inline]
 [<000000000ca14c79>] check_cpu_stall kernel/rcu/tree.c:1520 [inline]
 [<000000000ca14c79>] __rcu_pending kernel/rcu/tree.c:3495 [inline]
 [<000000000ca14c79>] rcu_pending kernel/rcu/tree.c:3559 [inline]
 [<000000000ca14c79>] rcu_check_callbacks.cold+0xcd6/0xd2f kernel/rcu/tree.c:2888
 [<00000000aef91a0d>] update_process_times+0x31/0x70 kernel/time/timer.c:1629
 [<0000000060854cba>] tick_sched_handle.isra.0+0x4a/0xf0 kernel/time/tick-sched.c:151
 [<00000000e690576e>] tick_sched_timer+0x7a/0x130 kernel/time/tick-sched.c:1190
 [<0000000088d9e626>] __run_hrtimer kernel/time/hrtimer.c:1255 [inline]
 [<0000000088d9e626>] __hrtimer_run_queues+0x313/0xe00 kernel/time/hrtimer.c:1319
 [<00000000743fa032>] hrtimer_interrupt+0x1b6/0x450 kernel/time/hrtimer.c:1353
 [<00000000f16888de>] local_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:937
 [<0000000087370bb6>] smp_apic_timer_interrupt+0x79/0xb0 arch/x86/kernel/apic/apic.c:961
 [<0000000042a7829a>] apic_timer_interrupt+0x9d/0xb0 arch/x86/entry/entry_64.S:648
 <EOI> [  272.952169]  [<0000000012335029>] ? arch_local_irq_restore arch/x86/include/asm/paravirt.h:768 [inline]
 <EOI> [  272.952169]  [<0000000012335029>] ? lock_acquire+0x176/0x3d0 kernel/locking/lockdep.c:3762
 [<00000000ddee93f9>] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline]
 [<00000000ddee93f9>] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151
 [<00000000b492c4d4>] spin_lock include/linux/spinlock.h:302 [inline]
 [<00000000b492c4d4>] ext4_do_update_inode fs/ext4/inode.c:4905 [inline]
 [<00000000b492c4d4>] ext4_mark_iloc_dirty+0x1d1/0x2850 fs/ext4/inode.c:5472
 [<00000000261e215c>] ext4_mark_inode_dirty+0x3db/0xb30 fs/ext4/inode.c:5588
 [<0000000087c10fbd>] ext4_dirty_inode+0x73/0xa0 fs/ext4/inode.c:5619
 [<000000001485eb38>] __mark_inode_dirty+0x10e/0x10a0 fs/fs-writeback.c:2097
 [<00000000f1fbc14a>] mark_inode_dirty include/linux/fs.h:2013 [inline]
 [<00000000f1fbc14a>] generic_write_end+0x195/0x260 fs/buffer.c:2180
 [<000000004fe3a8a6>] ext4_da_write_end+0x461/0xc20 fs/ext4/inode.c:3086
 [<00000000960403a2>] generic_perform_write+0x2fa/0x500 mm/filemap.c:2950
 [<000000009db89091>] __generic_file_write_iter+0x340/0x530 mm/filemap.c:3064
 [<00000000e05d7fa8>] ext4_file_write_iter+0x66e/0xdd0 fs/ext4/file.c:165
 [<000000002aa19711>] vfs_iter_write+0x2e2/0x580 fs/read_write.c:390
 [<00000000dcdca8dd>] iter_file_splice_write+0x5a9/0xb10 fs/splice.c:768
 [<00000000a362389d>] do_splice_from fs/splice.c:870 [inline]
 [<00000000a362389d>] direct_splice_actor+0x126/0x1a0 fs/splice.c:1037
 [<000000005eed3f39>] splice_direct_to_actor+0x2c8/0x820 fs/splice.c:992
 [<000000009878c073>] do_splice_direct+0x1a5/0x260 fs/splice.c:1080
 [<00000000834eef08>] do_sendfile+0x503/0xc00 fs/read_write.c:1401
 [<00000000e8b6f267>] SYSC_sendfile64 fs/read_write.c:1462 [inline]
 [<00000000e8b6f267>] SyS_sendfile64+0x145/0x160 fs/read_write.c:1448
 [<000000000e528bc4>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285
 [<0000000084d38d86>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
rcu_preempt kthread starved for 10555 jiffies! g570 c569 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0
rcu_preempt     R  running task    28856     7      2 0x80000000
 ffff8801da6817c0 ffff8801d1a2c780 ffff8801db721000 ffff8801cc93df00
 ffff8801db721018 ffff8801da697a70 ffffffff8280185e ffff8801da6817c0
 ffff8801da6979b8 00ffffff812445d1 ffff8801db7218f0 1ffff1003b4d2f3d
Call Trace:
 [<00000000781472c1>] schedule+0x92/0x1c0 kernel/sched/core.c:3546
 [<000000001fb81289>] schedule_timeout+0x513/0xe50 kernel/time/timer.c:1794
 [<0000000093c2983c>] rcu_gp_kthread+0xba5/0x20e0 kernel/rcu/tree.c:2235
 [<000000004a8d5e78>] kthread+0x278/0x310 kernel/kthread.c:211
 [<00000000aa4b7d82>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373