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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_single_inode

write to 0xffff888106a95f28 of 4 bytes by task 15202 on cpu 0:
 writeback_single_inode+0x14f/0x3f0 fs/fs-writeback.c:1798
 sync_inode_metadata+0x5c/0x90 fs/fs-writeback.c:2871
 __generic_file_fsync+0xed/0x140 fs/libfs.c:1543
 fat_file_fsync+0x46/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x116/0x130 fs/sync.c:187
 generic_write_sync include/linux/fs.h:2904 [inline]
 generic_file_write_iter+0x185/0x1c0 mm/filemap.c:4186
 iter_file_splice_write+0x5f1/0x980 fs/splice.c:743
 do_splice_from fs/splice.c:941 [inline]
 direct_splice_actor+0x160/0x2c0 fs/splice.c:1164
 splice_direct_to_actor+0x302/0x670 fs/splice.c:1108
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 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 0xffff888106a95f28 of 4 bytes by task 15214 on cpu 1:
 __mark_inode_dirty+0x198/0x7e0 fs/fs-writeback.c:2537
 fat_update_time+0x1e8/0x200 fs/fat/misc.c:357
 inode_update_time fs/inode.c:2124 [inline]
 touch_atime+0x14f/0x350 fs/inode.c:2197
 file_accessed include/linux/fs.h:2539 [inline]
 filemap_splice_read+0x8a5/0x910 mm/filemap.c:2978
 do_splice_read fs/splice.c:985 [inline]
 splice_direct_to_actor+0x269/0x670 fs/splice.c:1089
 do_splice_direct_actor fs/splice.c:1207 [inline]
 do_splice_direct+0xd7/0x150 fs/splice.c:1233
 do_sendfile+0x398/0x660 fs/read_write.c:1363
 __do_sys_sendfile64 fs/read_write.c:1424 [inline]
 __se_sys_sendfile64 fs/read_write.c:1410 [inline]
 __x64_sys_sendfile64+0x110/0x150 fs/read_write.c:1410
 x64_sys_call+0xfbd/0x2dc0 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: 0x00000038 -> 0x00000002

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 15214 Comm: syz.0.4337 Tainted: G        W          6.12.0-syzkaller-10740-g509f806f7f70 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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