syzbot

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BUG: KCSAN: data-race in dont_mount / step_into

read-write to 0xffff888106a7d780 of 4 bytes by task 3304 on cpu 1:
 dont_mount+0x2a/0x40 include/linux/dcache.h:375
 vfs_unlink+0x28f/0x420 fs/namei.c:4588
 do_unlinkat+0x28e/0x4c0 fs/namei.c:4650
 __do_sys_unlink fs/namei.c:4696 [inline]
 __se_sys_unlink fs/namei.c:4694 [inline]
 __x64_sys_unlink+0x2e/0x40 fs/namei.c:4694
 x64_sys_call+0x22a6/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:88
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888106a7d780 of 4 bytes by task 3007 on cpu 0:
 __follow_mount_rcu fs/namei.c:1572 [inline]
 handle_mounts fs/namei.c:1623 [inline]
 step_into+0xe3/0x820 fs/namei.c:1976
 walk_component+0x162/0x220 fs/namei.c:2144
 lookup_last fs/namei.c:2639 [inline]
 path_lookupat+0xfe/0x2a0 fs/namei.c:2663
 filename_lookup+0x147/0x340 fs/namei.c:2692
 do_readlinkat+0x7d/0x320 fs/stat.c:576
 __do_sys_readlink fs/stat.c:613 [inline]
 __se_sys_readlink fs/stat.c:610 [inline]
 __x64_sys_readlink+0x47/0x60 fs/stat.c:610
 x64_sys_call+0x2cf3/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:90
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00300008 -> 0x00004008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3007 Comm: udevd Not tainted 6.15.0-syzkaller-10769-g7d4e49a77d99 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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