syzbot

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BUG: KCSAN: data-race in __count_memcg_events / mem_cgroup_css_rstat_flush

write to 0xffff888237c344c0 of 4 bytes by task 27 on cpu 1:
 mem_cgroup_css_rstat_flush+0x4ea/0x540 mm/memcontrol.c:5848
 cgroup_rstat_flush_locked+0x848/0x980 kernel/cgroup/rstat.c:245
 cgroup_rstat_flush+0x26/0x40 kernel/cgroup/rstat.c:277
 do_flush_stats mm/memcontrol.c:745 [inline]
 flush_memcg_stats_dwork+0x50/0x90 mm/memcontrol.c:782
 process_one_work kernel/workqueue.c:3267 [inline]
 process_scheduled_works+0x465/0x990 kernel/workqueue.c:3348
 worker_thread+0x526/0x730 kernel/workqueue.c:3429
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read-write to 0xffff888237c344c0 of 4 bytes by task 9284 on cpu 0:
 memcg_rstat_updated mm/memcontrol.c:725 [inline]
 __count_memcg_events+0xce/0x130 mm/memcontrol.c:962
 mem_cgroup_charge_statistics mm/memcontrol.c:990 [inline]
 mem_cgroup_commit_charge+0x92/0x200 mm/memcontrol.c:2975
 charge_memcg mm/memcontrol.c:7288 [inline]
 __mem_cgroup_charge+0x75/0x100 mm/memcontrol.c:7299
 mem_cgroup_charge include/linux/memcontrol.h:691 [inline]
 folio_prealloc mm/memory.c:1054 [inline]
 wp_page_copy mm/memory.c:3263 [inline]
 do_wp_page+0x63b/0x1e70 mm/memory.c:3660
 handle_pte_fault mm/memory.c:5316 [inline]
 __handle_mm_fault mm/memory.c:5441 [inline]
 handle_mm_fault+0xb7f/0x27e0 mm/memory.c:5606
 do_user_addr_fault arch/x86/mm/fault.c:1331 [inline]
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x3eb/0x690 arch/x86/mm/fault.c:1532
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x0000001f -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9284 Comm: syz-executor.2 Not tainted 6.9.0-rc7-syzkaller-00012-gdccb07f2914c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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