syzbot

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BUG: KCSAN: data-race in generic_permission / setattr_copy

write to 0xffff8881004a4128 of 2 bytes by task 3979 on cpu 0:
 setattr_copy+0x29d/0x2c0 fs/attr.c:319
 ext4_setattr+0x3d4/0xeb0 fs/ext4/inode.c:5465
 notify_change+0x814/0x8a0 fs/attr.c:497
 chmod_common+0x13c/0x270 fs/open.c:650
 do_fchmodat fs/open.c:698 [inline]
 __do_sys_chmod fs/open.c:722 [inline]
 __se_sys_chmod fs/open.c:720 [inline]
 __x64_sys_chmod+0x95/0x120 fs/open.c:720
 x64_sys_call+0x826/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:91
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881004a4128 of 2 bytes by task 2786 on cpu 1:
 acl_permission_check fs/namei.c:341 [inline]
 generic_permission+0x28/0x380 fs/namei.c:407
 do_inode_permission fs/namei.c:468 [inline]
 inode_permission+0x77/0x300 fs/namei.c:528
 may_lookup fs/namei.c:1718 [inline]
 link_path_walk+0x15e/0x810 fs/namei.c:2273
 path_openat+0x1a1/0x1d80 fs/namei.c:3795
 do_filp_open+0xf7/0x200 fs/namei.c:3826
 do_sys_openat2+0xab/0x120 fs/open.c:1406
 do_sys_open fs/open.c:1421 [inline]
 __do_sys_openat fs/open.c:1437 [inline]
 __se_sys_openat fs/open.c:1432 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1432
 x64_sys_call+0x2cad/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x41ed -> 0x4002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 2786 Comm: udevd Not tainted 6.9.0-rc5-syzkaller-00296-g5eb4573ea63d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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