syzbot

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BUG: KCSAN: data-race in d_set_mounted / step_into

write to 0xffff88810ecc9780 of 4 bytes by task 23256 on cpu 0:
 d_set_mounted+0xfc/0x190 fs/dcache.c:1492
 get_mountpoint+0x1be/0x300 fs/namespace.c:755
 lock_mount+0x86/0x1d0 fs/namespace.c:2224
 do_new_mount_fc fs/namespace.c:2846 [inline]
 do_new_mount fs/namespace.c:2905 [inline]
 path_mount+0x18a4/0x1c00 fs/namespace.c:3233
 do_mount fs/namespace.c:3246 [inline]
 __do_sys_mount fs/namespace.c:3454 [inline]
 __se_sys_mount+0x23d/0x2e0 fs/namespace.c:3431
 __x64_sys_mount+0x63/0x70 fs/namespace.c:3431
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810ecc9780 of 4 bytes by task 23266 on cpu 1:
 __d_entry_type include/linux/dcache.h:394 [inline]
 d_is_symlink include/linux/dcache.h:424 [inline]
 step_into+0x158/0xec0 fs/namei.c:1773
 open_last_lookups fs/namei.c:3312 [inline]
 path_openat+0x105e/0x21b0 fs/namei.c:3495
 do_filp_open+0xbd/0x1d0 fs/namei.c:3525
 do_sys_openat2+0xa3/0x250 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1207
 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: 23266 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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