syzbot

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BUG: KCSAN: data-race in __d_lookup / shrink_dentry_list

read-write to 0xffff888153c80780 of 4 bytes by task 12240 on cpu 0:
 d_shrink_del fs/dcache.c:525 [inline]
 shrink_dentry_list+0x22d/0x3d0 fs/dcache.c:1214
 shrink_dcache_sb+0x15d/0x290 fs/dcache.c:1343
 reconfigure_super+0x142/0x590 fs/super.c:1058
 do_remount fs/namespace.c:3400 [inline]
 path_mount+0xaf7/0xbc0 fs/namespace.c:4146
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4360
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4360
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888153c80780 of 4 bytes by task 8596 on cpu 1:
 d_same_name fs/dcache.c:2287 [inline]
 __d_lookup+0x118/0x340 fs/dcache.c:2525
 lookup_fast+0x5e/0x320 fs/namei.c:1873
 lookup_fast_for_open fs/namei.c:4548 [inline]
 open_last_lookups fs/namei.c:4582 [inline]
 path_openat+0x436/0x2050 fs/namei.c:4855
 do_file_open+0x16c/0x290 fs/namei.c:4887
 do_sys_openat2+0x94/0x130 fs/open.c:1364
 do_sys_open fs/open.c:1370 [inline]
 __do_sys_openat fs/open.c:1386 [inline]
 __se_sys_openat fs/open.c:1381 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1381
 x64_sys_call+0x1e39/0x3020 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00140444 -> 0x00100044

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 8596 Comm: syz-executor Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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