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BUG: KCSAN: data-race in drain_all_stock / refill_stock

read to 0xffff88812c02a100 of 8 bytes by task 10141 on cpu 1:
 drain_all_stock mm/memcontrol.c:2158 [inline]
 drain_all_stock+0xd4/0x250 mm/memcontrol.c:2138
 try_charge+0x79b/0xbf0 mm/memcontrol.c:2462
 __memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
 __memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
 __alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
 alloc_pages_current+0xd1/0x170 mm/mempolicy.c:2207
 alloc_pages include/linux/gfp.h:532 [inline]
 pmd_alloc_one arch/x86/include/asm/pgalloc.h:96 [inline]
 __pmd_alloc+0x4b/0x2b0 mm/memory.c:4193
 pmd_alloc include/linux/mm.h:1865 [inline]
 copy_pmd_range mm/memory.c:872 [inline]
 copy_pud_range mm/memory.c:926 [inline]
 copy_p4d_range mm/memory.c:948 [inline]
 copy_page_range+0x1529/0x19b0 mm/memory.c:1010
 dup_mmap kernel/fork.c:604 [inline]
 dup_mm+0x74a/0xba0 kernel/fork.c:1360
 copy_mm kernel/fork.c:1416 [inline]
 copy_process+0x3138/0x3c40 kernel/fork.c:2072
 _do_fork+0xfe/0x7a0 kernel/fork.c:2421
 __do_sys_clone kernel/fork.c:2576 [inline]
 __se_sys_clone kernel/fork.c:2557 [inline]
 __x64_sys_clone+0x130/0x170 kernel/fork.c:2557
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812c02a100 of 8 bytes by task 2816 on cpu 0:
 refill_stock+0xaa/0x110 mm/memcontrol.c:2124
 try_charge+0xa60/0xbf0 mm/memcontrol.c:2534
 __memcg_kmem_charge_memcg+0x4a/0xe0 mm/memcontrol.c:2837
 __memcg_kmem_charge+0xcf/0x1b0 mm/memcontrol.c:2877
 __alloc_pages_nodemask+0x26c/0x310 mm/page_alloc.c:4780
 alloc_pages_current+0xd1/0x170 mm/mempolicy.c:2207
 alloc_pages include/linux/gfp.h:532 [inline]
 __get_free_pages mm/page_alloc.c:4800 [inline]
 get_zeroed_page+0x14/0x50 mm/page_alloc.c:4809
 pud_alloc_one arch/x86/include/asm/pgalloc.h:156 [inline]
 __pud_alloc+0x48/0x250 mm/memory.c:4160
 pud_alloc+0xc3/0x100 include/linux/mm.h:1858
 copy_pud_range mm/memory.c:906 [inline]
 copy_p4d_range mm/memory.c:948 [inline]
 copy_page_range+0x270/0x19b0 mm/memory.c:1010
 dup_mmap kernel/fork.c:604 [inline]
 dup_mm+0x74a/0xba0 kernel/fork.c:1360
 copy_mm kernel/fork.c:1416 [inline]
 copy_process+0x3138/0x3c40 kernel/fork.c:2072
 _do_fork+0xfe/0x7a0 kernel/fork.c:2421
 __do_sys_clone kernel/fork.c:2576 [inline]
 __se_sys_clone kernel/fork.c:2557 [inline]
 __x64_sys_clone+0x130/0x170 kernel/fork.c:2557
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 2816 Comm: syz-executor.5 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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