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BUG: KCSAN: data-race in __mark_inode_dirty / generic_buffers_fsync_noflush

write to 0xffff888106b8a008 of 4 bytes by task 6326 on cpu 1:
 __mark_inode_dirty+0x240/0x760 fs/fs-writeback.c:2558
 generic_update_time fs/inode.c:2064 [inline]
 inode_update_time fs/inode.c:2077 [inline]
 __file_update_time fs/inode.c:2305 [inline]
 file_modified_flags+0x324/0x350 fs/inode.c:2376
 file_modified+0x17/0x20 fs/inode.c:2392
 ext4_write_checks fs/ext4/file.c:279 [inline]
 ext4_buffered_write_iter+0x1d0/0x3c0 fs/ext4/file.c:295
 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1
 iter_file_splice_write+0x5f2/0x970 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x153/0x2a0 fs/splice.c:1158
 splice_direct_to_actor+0x30f/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 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 0xffff888106b8a008 of 4 bytes by task 6307 on cpu 0:
 generic_buffers_fsync_noflush+0x80/0x120 fs/buffer.c:614
 ext4_fsync_nojournal fs/ext4/fsync.c:88 [inline]
 ext4_sync_file+0x1ab/0x690 fs/ext4/fsync.c:147
 vfs_fsync_range+0x10d/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:3027 [inline]
 ext4_buffered_write_iter+0x34f/0x3c0 fs/ext4/file.c:305
 ext4_file_write_iter+0x383/0xf00 fs/ext4/file.c:-1
 iter_file_splice_write+0x5f2/0x970 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x153/0x2a0 fs/splice.c:1158
 splice_direct_to_actor+0x30f/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x650 fs/read_write.c:1370
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1417
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 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: 0x00000000 -> 0x00000028

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6307 Comm: syz.2.1031 Not tainted 6.16.0-rc1-syzkaller-00157-g02adc1490e6d #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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