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BUG: KCSAN: data-race in yama_relation_cleanup / yama_task_free

write to 0xffff88808dd912d0 of 1 bytes by interrupt on cpu 1:
 yama_ptracer_del security/yama/yama_lsm.c:191 [inline]
 yama_task_free+0xc6/0x150 security/yama/yama_lsm.c:207
 security_task_free+0x3f/0xa0 security/security.c:1595
 __put_task_struct+0x96/0x370 kernel/fork.c:750
 put_task_struct include/linux/sched/task.h:126 [inline]
 delayed_put_task_struct+0x52/0x160 kernel/exit.c:172
 rcu_do_batch kernel/rcu/tree.c:2414 [inline]
 rcu_core+0x576/0xac0 kernel/rcu/tree.c:2641
 rcu_core_si+0x9/0x10 kernel/rcu/tree.c:2650
 __do_softirq+0x198/0x360 kernel/softirq.c:292
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:711
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 do_softirq_own_stack+0x5d/0x80 arch/x86/kernel/irq_64.c:77
 invoke_softirq kernel/softirq.c:387 [inline]
 __irq_exit_rcu+0x115/0x120 kernel/softirq.c:417
 sysvec_apic_timer_interrupt+0xba/0xd0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:587
 arch_local_irq_restore arch/x86/include/asm/paravirt.h:765 [inline]
 kcsan_setup_watchpoint+0x47c/0x4d0 kernel/kcsan/core.c:542
 unlock_page_memcg+0x2e/0xc0 mm/memcontrol.c:2035
 page_remove_rmap+0x26f/0x2e0 mm/rmap.c:1367
 zap_pte_range+0x702/0x1610 mm/memory.c:1089
 zap_pmd_range mm/memory.c:1193 [inline]
 zap_pud_range mm/memory.c:1222 [inline]
 zap_p4d_range mm/memory.c:1243 [inline]
 unmap_page_range+0x751/0x870 mm/memory.c:1264
 unmap_single_vma+0x157/0x210 mm/memory.c:1309
 unmap_vmas+0xc0/0x150 mm/memory.c:1341
 exit_mmap+0x1c7/0x3b0 mm/mmap.c:3150
 __mmput+0xa2/0x220 kernel/fork.c:1093
 mmput+0x38/0x40 kernel/fork.c:1114
 exit_mm+0x2c8/0x330 kernel/exit.c:482
 do_exit+0x415/0x16e0 kernel/exit.c:792
 do_group_exit+0xcb/0x180 kernel/exit.c:903
 get_signal+0x106d/0x1650 kernel/signal.c:2743
 do_signal+0x25/0x270 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline]
 __prepare_exit_to_usermode+0x127/0x230 arch/x86/entry/common.c:269
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:352
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:393
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88808dd912d0 of 1 bytes by task 9081 on cpu 0:
 yama_relation_cleanup+0x5d/0x150 security/yama/yama_lsm.c:122
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9081 Comm: kworker/0:3 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events yama_relation_cleanup
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