loop2: detected capacity change from 0 to 262160
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BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers

write to 0xffff88812f1a7ef8 of 8 bytes by task 14336 on cpu 0:
 __remove_assoc_queue fs/buffer.c:481 [inline]
 fsync_buffers_list fs/buffer.c:688 [inline]
 sync_mapping_buffers+0x155/0x8b0 fs/buffer.c:548
 fat_file_fsync+0xa9/0x100 fs/fat/file.c:194
 vfs_fsync_range+0x107/0x120 fs/sync.c:200
 generic_write_sync include/linux/fs.h:2987 [inline]
 generic_file_write_iter+0x103/0x130 mm/filemap.c:3819
 call_write_iter include/linux/fs.h:2114 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0x69d/0x770 fs/read_write.c:605
 ksys_write+0xce/0x180 fs/read_write.c:658
 __do_sys_write fs/read_write.c:670 [inline]
 __se_sys_write fs/read_write.c:667 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:667
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88812f1a7ef8 of 8 bytes by task 14325 on cpu 1:
 mark_buffer_dirty_inode+0x92/0x1d0 fs/buffer.c:581
 fat_mirror_bhs+0x205/0x330 fs/fat/fatent.c:396
 fat_ent_write+0xc2/0xd0 fs/fat/fatent.c:421
 fat_free fs/fat/file.c:362 [inline]
 fat_truncate_blocks+0x339/0x550 fs/fat/file.c:393
 fat_write_failed fs/fat/inode.c:224 [inline]
 fat_write_begin+0xd0/0xf0 fs/fat/inode.c:239
 generic_perform_write+0x196/0x3c0 mm/filemap.c:3656
 __generic_file_write_iter+0x161/0x300 mm/filemap.c:3783
 generic_file_write_iter+0x75/0x130 mm/filemap.c:3815
 call_write_iter include/linux/fs.h:2114 [inline]
 aio_write+0x287/0x360 fs/aio.c:1578
 __io_submit_one fs/aio.c:1837 [inline]
 io_submit_one+0x82f/0x1350 fs/aio.c:1880
 __do_sys_io_submit fs/aio.c:1939 [inline]
 __se_sys_io_submit+0xf5/0x260 fs/aio.c:1909
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1909
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff88812f16b820 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 14325 Comm: syz-executor.2 Tainted: G        W         5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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