syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_single_inode

write to 0xffff888107e8a288 of 8 bytes by task 14520 on cpu 1:
 writeback_single_inode+0x10e/0x4a0 fs/fs-writeback.c:1768
 sync_inode_metadata+0x5c/0x90 fs/fs-writeback.c:2833
 __generic_file_fsync+0xf9/0x140 fs/libfs.c:1484
 fat_file_fsync+0x4c/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x122/0x140 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2793 [inline]
 generic_file_write_iter+0x191/0x1d0 mm/filemap.c:4099
 call_write_iter include/linux/fs.h:2108 [inline]
 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+0x3b9/0x970 fs/read_write.c:1295
 __do_sys_sendfile64 fs/read_write.c:1356 [inline]
 __se_sys_sendfile64 fs/read_write.c:1348 [inline]
 __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1348
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffff888107e8a288 of 8 bytes by task 14529 on cpu 0:
 __mark_inode_dirty+0x58/0x7e0 fs/fs-writeback.c:2459
 fat_update_time+0x1fe/0x210 fs/fat/misc.c:357
 inode_update_time fs/inode.c:1919 [inline]
 touch_atime+0x14f/0x350 fs/inode.c:1992
 file_accessed include/linux/fs.h:2457 [inline]
 filemap_splice_read+0x8b0/0x920 mm/filemap.c:2926
 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+0x3b9/0x970 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
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x0000000000000007 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14529 Comm: syz-executor.3 Not tainted 6.8.0-syzkaller-11567-gb3603fcb79b1 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
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