syzbot

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BUG: KCSAN: data-race in mm_update_next_owner / stop_this_handle

write to 0xffff88800f42e02c of 4 bytes by task 1182 on cpu 0:
 memalloc_nofs_restore include/linux/sched/mm.h:258 [inline]
 stop_this_handle+0x2ae/0x2f0 fs/jbd2/transaction.c:744
 jbd2_journal_stop+0x573/0x6d0 fs/jbd2/transaction.c:1907
 __ext4_journal_stop+0x99/0x110 fs/ext4/ext4_jbd2.c:127
 ext4_evict_inode+0xc04/0xef0 fs/ext4/inode.c:334
 evict+0x1aa/0x410 fs/inode.c:578
 iput_final fs/inode.c:1654 [inline]
 iput+0x3fd/0x520 fs/inode.c:1680
 dentry_unlink_inode+0x210/0x220 fs/dcache.c:374
 d_delete+0x78/0xa0 fs/dcache.c:2503
 vfs_rmdir+0x28a/0x2a0 fs/namei.c:3913
 do_rmdir+0x186/0x310 fs/namei.c:3962
 __do_sys_rmdir fs/namei.c:3980 [inline]
 __se_sys_rmdir fs/namei.c:3978 [inline]
 __x64_sys_rmdir+0x2c/0x30 fs/namei.c:3978
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88800f42e02c of 4 bytes by task 8101 on cpu 1:
 mm_update_next_owner+0x1d9/0x4e0 kernel/exit.c:388
 exit_mm+0x33c/0x430 kernel/exit.c:500
 do_exit+0x3ff/0x1670 kernel/exit.c:812
 do_group_exit+0x17d/0x180 kernel/exit.c:922
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:933
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:931
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:931
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8101 Comm: syz-executor.1 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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