==================================================================
BUG: KCSAN: data-race in __mark_inode_dirty / writeback_single_inode

write to 0xffff888124ecc430 of 8 bytes by task 5778 on cpu 0:
 writeback_single_inode+0x109/0x4f0 fs/fs-writeback.c:1699
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2724
 __generic_file_fsync+0xf5/0x140 fs/libfs.c:1126
 fat_file_fsync+0x48/0x100 fs/fat/file.c:190
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2744 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3933
 call_write_iter include/linux/fs.h:2060 [inline]
 new_sync_write fs/read_write.c:504 [inline]
 vfs_write+0x71c/0x890 fs/read_write.c:591
 ksys_write+0xe8/0x1a0 fs/read_write.c:644
 __do_sys_write fs/read_write.c:656 [inline]
 __se_sys_write fs/read_write.c:653 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:653
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

read to 0xffff888124ecc430 of 8 bytes by task 5772 on cpu 1:
 __mark_inode_dirty+0xd5/0x5f0 fs/fs-writeback.c:2395
 fat_update_time+0x2c9/0x300 fs/fat/misc.c:359
 inode_update_time fs/inode.c:1868 [inline]
 touch_atime+0x16e/0x2e0 fs/inode.c:1941
 file_accessed include/linux/fs.h:2388 [inline]
 generic_file_splice_read+0x237/0x2c0 fs/splice.c:314
 do_splice_to fs/splice.c:796 [inline]
 splice_direct_to_actor+0x2ac/0x660 fs/splice.c:870
 do_splice_direct+0xfb/0x180 fs/splice.c:979
 do_sendfile+0x3ad/0x900 fs/read_write.c:1246
 __do_sys_sendfile64 fs/read_write.c:1305 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0xb9/0x150 fs/read_write.c:1297
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x46/0xb0

value changed: 0x0000000000000005 -> 0x0000000000000080

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5772 Comm: syz-executor.2 Not tainted 5.18.0-syzkaller-11080-g664a393a2663-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================