syzbot

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BUG: KCSAN: data-race in __mark_inode_dirty / __mark_inode_dirty

read-write to 0xffff888129a3bce0 of 8 bytes by task 5540 on cpu 1:
 __mark_inode_dirty+0x1ed/0x5f0 fs/fs-writeback.c:2410
 mark_buffer_dirty+0x176/0x390 fs/buffer.c:1109
 __block_commit_write fs/buffer.c:2080 [inline]
 block_write_end+0x13d/0x240 fs/buffer.c:2159
 generic_write_end+0x5d/0x230 fs/buffer.c:2173
 fat_write_end+0x4a/0x150 fs/fat/inode.c:249
 generic_perform_write+0x264/0x3f0 mm/filemap.c:3775
 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3892
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3924
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:852
 vfs_iter_write+0x4c/0x70 fs/read_write.c:893
 iter_file_splice_write+0x44a/0x7c0 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x660 fs/splice.c:891
 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

read to 0xffff888129a3bce0 of 8 bytes by task 5556 on cpu 0:
 __mark_inode_dirty+0x338/0x5f0 fs/fs-writeback.c:2447
 fat_update_time+0x124/0x140 fs/fat/misc.c:351
 inode_update_time fs/inode.c:1868 [inline]
 touch_atime+0x16e/0x2e0 fs/inode.c:1941
 file_accessed include/linux/fs.h:2369 [inline]
 filemap_read+0x137e/0x1400 mm/filemap.c:2747
 generic_file_read_iter+0x72/0x320 mm/filemap.c:2825
 call_read_iter include/linux/fs.h:2035 [inline]
 generic_file_splice_read+0x1de/0x2c0 fs/splice.c:311
 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:1311 [inline]
 __se_sys_sendfile64 fs/read_write.c:1297 [inline]
 __x64_sys_sendfile64+0x10c/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: 0x0000000000000001 -> 0x0000000000000007

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5556 Comm: syz-executor.4 Not tainted 5.18.0-syzkaller-02752-gfdaf9a5840ac-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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