syzbot

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BUG: KCSAN: data-race in exit_fs / ksys_unshare

read-write to 0xffff888101af7040 of 4 bytes by task 7875 on cpu 0:
 exit_fs+0x65/0xd0 fs/fs_struct.c:104
 do_exit+0x553/0x16e0 kernel/exit.c:791
 __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+0x63/0xcd

read to 0xffff888101af7040 of 4 bytes by task 7873 on cpu 1:
 unshare_fs kernel/fork.c:3094 [inline]
 ksys_unshare+0x237/0x6e0 kernel/fork.c:3172
 __do_sys_unshare kernel/fork.c:3252 [inline]
 __se_sys_unshare kernel/fork.c:3250 [inline]
 __x64_sys_unshare+0x1b/0x20 kernel/fork.c:3250
 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+0x63/0xcd

value changed: 0x00000006 -> 0x00000005

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7873 Comm: syz-executor.3 Not tainted 6.0.0-rc7-syzkaller-00250-ga962b54e162c-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
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