syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
	(detected by 1, t=10502 jiffies, g=10585, q=179)
rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294967435-4294956932), jiffies_till_next_fqs=1, root ->qsmask 0x0
syz-executor.2  R  running task    21368  9406   9000 0x80004002
Call Trace:
 <IRQ>
 sched_show_task+0x411/0x560 kernel/sched/core.c:5952
 print_other_cpu_stall kernel/rcu/tree_stall.h:430 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:558 [inline]
 rcu_pending kernel/rcu/tree.c:3030 [inline]
 rcu_sched_clock_irq+0x188c/0x1aa0 kernel/rcu/tree.c:2276
 update_process_times+0x12d/0x180 kernel/time/timer.c:1726
 tick_sched_handle kernel/time/tick-sched.c:171 [inline]
 tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1314
 __run_hrtimer kernel/time/hrtimer.c:1517 [inline]
 __hrtimer_run_queues+0x3f3/0x840 kernel/time/hrtimer.c:1579
 hrtimer_interrupt+0x37c/0xda0 kernel/time/hrtimer.c:1641
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1119 [inline]
 smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1144
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829
 </IRQ>
RIP: 0010:__kasan_check_read+0x1/0x20 mm/kasan/common.c:94
Code: 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 65 48 8b 04 25 c0 1d 02 00 ff 88 68 13 00 00 5d c3 90 66 2e 0f 1f 84 00 00 00 00 00 55 <48> 89 e5 89 f6 48 8b 4d 08 31 d2 e8 4f 27 00 00 5d c3 0f 1f 00 66
RSP: 0018:ffffc900047aeac8 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff1212021 RBX: ffff8880aeb38018 RCX: 0000000000040000
RDX: ffffc9000f001000 RSI: 0000000000000004 RDI: ffff8880aeb38018
RBP: ffffc900047aeaf0 R08: ffffffff83a4b9c7 R09: ffffed1015d67004
R10: ffffed1015d67004 R11: 0000000000000000 R12: ffff88808c2c8010
R13: dffffc0000000000 R14: ffffffff89090108 R15: dffffc0000000000
 rcu_read_unlock include/linux/rcupdate.h:651 [inline]
 percpu_ref_tryget_many include/linux/percpu-refcount.h:237 [inline]
 percpu_ref_tryget+0xb6/0x1d0 include/linux/percpu-refcount.h:253
 css_tryget include/linux/cgroup.h:351 [inline]
 get_mem_cgroup_from_mm+0x124/0x1b0 mm/memcontrol.c:942
 mem_cgroup_try_charge+0x205/0x550 mm/memcontrol.c:6365
 __add_to_page_cache_locked+0x8ed/0xcf0 mm/filemap.c:844
 add_to_page_cache_lru+0x156/0x4a0 mm/filemap.c:921
 ext4_mpage_readpages+0x3e7/0x1df0 fs/ext4/readpage.c:259
 ext4_readpages+0xe8/0x120 fs/ext4/inode.c:3245
 read_pages+0xaa/0x4d0 mm/readahead.c:126
 __do_page_cache_readahead+0x480/0x530 mm/readahead.c:212
 ondemand_readahead+0x6bf/0xce0 mm/internal.h:62
 page_cache_async_readahead+0x2af/0x340 mm/readahead.c:574
 generic_file_buffered_read+0x4a6/0x2570 mm/filemap.c:2037
 generic_file_read_iter+0xa9/0x450 mm/filemap.c:2302
 ext4_file_read_iter+0x48e/0x770 fs/ext4/file.c:73
 call_read_iter include/linux/fs.h:1895 [inline]
 new_sync_read fs/read_write.c:414 [inline]
 __vfs_read+0x59e/0x730 fs/read_write.c:427
 integrity_kernel_read+0x113/0x190 security/integrity/iint.c:200
 ima_calc_file_hash_tfm security/integrity/ima/ima_crypto.c:360 [inline]
 ima_calc_file_shash security/integrity/ima/ima_crypto.c:391 [inline]
 ima_calc_file_hash+0xac7/0x1cd0 security/integrity/ima/ima_crypto.c:456
 ima_collect_measurement+0x244/0x4c0 security/integrity/ima/ima_api.c:249
 process_measurement+0xddc/0x18d0 security/integrity/ima/ima_main.c:326
 ima_file_check+0x9b/0xe0 security/integrity/ima/ima_main.c:442
 do_last fs/namei.c:3494 [inline]
 path_openat+0x1def/0x4380 fs/namei.c:3607
 do_filp_open+0x192/0x3d0 fs/namei.c:3637
 do_sys_openat2+0x42b/0x6f0 fs/open.c:1149
 do_sys_open fs/open.c:1165 [inline]
 ksys_open include/linux/syscalls.h:1386 [inline]
 __do_sys_open fs/open.c:1171 [inline]
 __se_sys_open fs/open.c:1169 [inline]
 __x64_sys_open+0x1bd/0x1e0 fs/open.c:1169
 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c6c9
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:00007f9be5ab0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 00007f9be5ab16d4 RCX: 000000000045c6c9
RDX: 0000000000000000 RSI: 0000000000141042 RDI: 0000000020000100
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000772 R14: 000000000050335f R15: 000000000076bf2c
rcu: rcu_preempt kthread starved for 10549 jiffies! g10585 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
rcu: RCU grace-period kthread stack dump:
rcu_preempt     R  running task    28952    10      2 0x80004000
Call Trace:
 context_switch kernel/sched/core.c:3380 [inline]
 __schedule+0x87f/0xcd0 kernel/sched/core.c:4080
 schedule+0x188/0x210 kernel/sched/core.c:4154
 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895
 rcu_gp_fqs_loop kernel/rcu/tree.c:1658 [inline]
 rcu_gp_kthread+0xe8d/0x17e0 kernel/rcu/tree.c:1818
 kthread+0x332/0x350 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352