syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / writeback_single_inode

write to 0xffff88811d5f2d30 of 8 bytes by task 7118 on cpu 1:
 writeback_single_inode+0x109/0x4f0 fs/fs-writeback.c:1705
 sync_inode_metadata+0x52/0x70 fs/fs-writeback.c:2743
 __generic_file_fsync+0xf5/0x140 fs/libfs.c:1126
 fat_file_fsync+0x48/0x100 fs/fat/file.c:191
 vfs_fsync_range+0x107/0x120 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2869 [inline]
 generic_file_write_iter+0x18d/0x1c0 mm/filemap.c:3902
 do_iter_write+0x494/0x750 fs/read_write.c:855
 vfs_iter_write+0x4c/0x70 fs/read_write.c:896
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:931
 splice_direct_to_actor+0x305/0x620 fs/splice.c:886
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0xb9/0x150 fs/read_write.c:1303
 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+0x63/0xcd

read to 0xffff88811d5f2d30 of 8 bytes by task 7125 on cpu 0:
 __mark_inode_dirty+0xd5/0x620 fs/fs-writeback.c:2402
 fat_update_time+0x2c9/0x300 fs/fat/misc.c:359
 inode_update_time fs/inode.c:1872 [inline]
 touch_atime+0x16e/0x2e0 fs/inode.c:1945
 file_accessed include/linux/fs.h:2516 [inline]
 filemap_read+0x13b7/0x1430 mm/filemap.c:2728
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2806
 call_read_iter include/linux/fs.h:2181 [inline]
 generic_file_splice_read+0xde/0x2b0 fs/splice.c:309
 do_splice_to fs/splice.c:793 [inline]
 splice_direct_to_actor+0x26c/0x620 fs/splice.c:865
 do_splice_direct+0xfb/0x180 fs/splice.c:974
 do_sendfile+0x3bf/0x910 fs/read_write.c:1249
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64 fs/read_write.c:1303 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
 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+0x63/0xcd

value changed: 0x0000000000000007 -> 0x0000000000000080

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7125 Comm: syz-executor.4 Not tainted 6.0.0-rc7-syzkaller-00029-g3800a713b607-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022
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