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BUG: KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode

write to 0xffff888138206058 of 8 bytes by task 6193 on cpu 0:
 mark_buffer_dirty_inode+0x18c/0x1b0 fs/buffer.c:585
 fat12_ent_put+0x11d/0x180 fs/fat/fatent.c:173
 fat_alloc_clusters+0x47d/0xa80 fs/fat/fatent.c:503
 fat_add_cluster fs/fat/inode.c:108 [inline]
 __fat_get_block fs/fat/inode.c:155 [inline]
 fat_get_block+0x263/0x600 fs/fat/inode.c:190
 __block_write_begin_int+0x33d/0xc90 fs/buffer.c:2006
 __block_write_begin fs/buffer.c:2056 [inline]
 block_write_begin+0x73/0x170 fs/buffer.c:2117
 cont_write_begin+0x3f1/0x520 fs/buffer.c:2468
 fat_write_begin+0x5d/0xe0 fs/fat/inode.c:235
 generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3779
 __generic_file_write_iter+0xe3/0x280 mm/filemap.c:3907
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3939
 do_iter_readv_writev+0x27b/0x300
 do_iter_write+0x16f/0x5c0 fs/read_write.c:868
 vfs_iter_write+0x4c/0x70 fs/read_write.c:909
 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+0x3bf/0x910 fs/read_write.c:1262
 __do_sys_sendfile64 fs/read_write.c:1330 [inline]
 __se_sys_sendfile64 fs/read_write.c:1316 [inline]
 __x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1316
 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 0xffff888138206058 of 8 bytes by task 6199 on cpu 1:
 mark_buffer_dirty_inode+0x92/0x1b0 fs/buffer.c:581
 fat12_ent_put+0x11d/0x180 fs/fat/fatent.c:173
 fat_ent_write+0x5e/0xd0 fs/fat/fatent.c:417
 fat_chain_add+0x15b/0x410 fs/fat/misc.c:136
 fat_add_cluster+0x74/0xd0 fs/fat/inode.c:113
 fat_fallocate+0x125/0x1c0 fs/fat/file.c:291
 vfs_fallocate+0x355/0x3d0 fs/open.c:323
 do_vfs_ioctl+0x12d9/0x1390 fs/ioctl.c:849
 __do_sys_ioctl fs/ioctl.c:868 [inline]
 __se_sys_ioctl+0x83/0x140 fs/ioctl.c:856
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:856
 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: 0x0000000000000000 -> 0xffff888138195210

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6199 Comm: syz-executor.3 Not tainted 5.19.0-rc8-syzkaller-00168-g334c0ef6429f-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
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