syzbot

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BUG: KCSAN: data-race in do_task_stat / handle_mm_fault

write to 0xffff88810139e688 of 8 bytes by task 31151 on cpu 1:
 mm_account_fault mm/memory.c:4570 [inline]
 handle_mm_fault+0x1613/0x1810 mm/memory.c:4634
 do_user_addr_fault+0x43e/0x830 arch/x86/mm/fault.c:1393
 handle_page_fault arch/x86/mm/fault.c:1450 [inline]
 exc_page_fault+0x94/0x2a0 arch/x86/mm/fault.c:1506
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580

read to 0xffff88810139e688 of 8 bytes by task 1 on cpu 0:
 do_task_stat+0x5ed/0x10c0 fs/proc/array.c:533
 proc_tgid_stat+0x2f/0x40 fs/proc/array.c:663
 proc_single_show+0x84/0x100 fs/proc/base.c:775
 seq_read_iter+0x2ef/0x910 fs/seq_file.c:227
 seq_read+0x221/0x260 fs/seq_file.c:159
 vfs_read+0x154/0x5d0 fs/read_write.c:494
 ksys_read+0xce/0x180 fs/read_write.c:634
 __do_sys_read fs/read_write.c:644 [inline]
 __se_sys_read fs/read_write.c:642 [inline]
 __x64_sys_read+0x3e/0x50 fs/read_write.c:642
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 1 Comm: systemd Not tainted 5.11.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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