==================================================================
BUG: KCSAN: data-race in atime_needs_update / inode_update_timestamps

write to 0xffff8881046cbc84 of 4 bytes by task 7469 on cpu 1:
 inode_set_mtime_to_ts include/linux/fs.h:1603 [inline]
 inode_update_timestamps+0x166/0x280 fs/inode.c:1927
 generic_update_time fs/inode.c:1962 [inline]
 inode_update_time fs/inode.c:1982 [inline]
 __file_update_time fs/inode.c:2171 [inline]
 file_modified_flags+0x2a1/0x340 fs/inode.c:2242
 file_modified+0x17/0x20 fs/inode.c:2258
 ext4_write_checks fs/ext4/file.c:279 [inline]
 ext4_buffered_write_iter+0x1d8/0x380 fs/ext4/file.c:295
 ext4_file_write_iter+0x29f/0xe30
 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xfc3/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881046cbc84 of 4 bytes by task 7476 on cpu 0:
 inode_get_mtime_nsec include/linux/fs.h:1589 [inline]
 inode_get_mtime include/linux/fs.h:1595 [inline]
 relatime_need_update fs/inode.c:1876 [inline]
 atime_needs_update+0x2aa/0x3e0 fs/inode.c:2022
 touch_atime+0x4a/0x350 fs/inode.c:2037
 file_accessed include/linux/fs.h:2480 [inline]
 filemap_splice_read+0x8b0/0x920 mm/filemap.c:2950
 ext4_file_splice_read+0x95/0xc0 fs/ext4/file.c:158
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x26c/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x3ab/0x950 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1362 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1348
 x64_sys_call+0xfc3/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0cf0df7d -> 0x0d8975fd

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 7476 Comm: syz.0.1200 Not tainted 6.10.0-syzkaller-12708-g2f8c4f506285 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
==================================================================