loop8: detected capacity change from 0 to 1024
EXT4-fs (loop8): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
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BUG: KCSAN: data-race in _copy_to_iter / memcpy_and_pad

read to 0xffff88813a8f0400 of 1024 bytes by task 5110 on cpu 1:
 instrument_copy_to_user include/linux/instrumented.h:113 [inline]
 copy_to_user_iter lib/iov_iter.c:24 [inline]
 iterate_ubuf include/linux/iov_iter.h:30 [inline]
 iterate_and_advance2 include/linux/iov_iter.h:302 [inline]
 iterate_and_advance include/linux/iov_iter.h:330 [inline]
 _copy_to_iter+0x130/0xe70 lib/iov_iter.c:185
 copy_page_to_iter+0x18f/0x2d0 lib/iov_iter.c:362
 copy_folio_to_iter include/linux/uio.h:204 [inline]
 filemap_read+0x407/0xa00 mm/filemap.c:2763
 blkdev_read_iter+0x22d/0x2e0 block/fops.c:849
 new_sync_read fs/read_write.c:491 [inline]
 vfs_read+0x64c/0x770 fs/read_write.c:572
 ksys_read+0xda/0x1a0 fs/read_write.c:715
 __do_sys_read fs/read_write.c:724 [inline]
 __se_sys_read fs/read_write.c:722 [inline]
 __x64_sys_read+0x40/0x50 fs/read_write.c:722
 x64_sys_call+0x27bc/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:1
 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

write to 0xffff88813a8f0488 of 10 bytes by task 16712 on cpu 0:
 memcpy_and_pad+0x48/0x80 lib/string_helpers.c:1007
 ext4_sample_last_mounted fs/ext4/file.c:879 [inline]
 ext4_file_open+0x53d/0x600 fs/ext4/file.c:901
 do_dentry_open+0x649/0xa20 fs/open.c:965
 vfs_open+0x37/0x1e0 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1c5e/0x2170 fs/namei.c:4046
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16712 Comm: syz.8.4028 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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