syzbot

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BUG: KCSAN: data-race in exit_mm / mm_update_next_owner

write to 0xffff8881297229c8 of 8 bytes by task 5142 on cpu 1:
 exit_mm+0x98/0x170 kernel/exit.c:503
 do_exit+0x51d/0x1720 kernel/exit.c:782
 do_group_exit+0xa5/0x160 kernel/exit.c:925
 get_signal+0xf54/0x1020 kernel/signal.c:2875
 arch_do_signal_or_restart+0x87/0x2d0 arch/x86/kernel/signal.c:869
 exit_to_user_mode_loop+0x78/0x130 kernel/entry/common.c:166
 exit_to_user_mode_prepare kernel/entry/common.c:201 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x6a/0x90 kernel/entry/common.c:294
 do_syscall_64+0x37/0x70 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff8881297229c8 of 8 bytes by task 5132 on cpu 0:
 mm_update_next_owner+0x23c/0x4e0 kernel/exit.c:435
 exit_mm+0xd3/0x170 kernel/exit.c:509
 do_exit+0x51d/0x1720 kernel/exit.c:782
 __x64_sys_exit_group+0x0/0x20 kernel/exit.c:925
 __do_sys_exit_group kernel/exit.c:936 [inline]
 __se_sys_exit_group kernel/exit.c:934 [inline]
 __x64_sys_exit_group+0x1b/0x20 kernel/exit.c:934
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0xffff8881084be800 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5132 Comm: syz-executor.5 Not tainted 5.18.0-syzkaller-02752-gfdaf9a5840ac-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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