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author | Ryusuke Konishi <konishi.ryusuke@gmail.com> | 2024-05-11 03:29:42 +0300 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-20 00:36:21 +0300 |
commit | db3e24a02e29b507c24c0adb4d22914c65dab763 (patch) | |
tree | d2cbd7f222886dd7d159fd9713ebc392cdf7f6f3 /arch/x86/video/fbdev.c | |
parent | 28d2188709d9c19a7c4601c6870edd9fa0527379 (diff) | |
download | linux-db3e24a02e29b507c24c0adb4d22914c65dab763.tar.xz |
nilfs2: make block erasure safe in nilfs_finish_roll_forward()
The implementation of writing a zero-fill block in
nilfs_finish_roll_forward() is not safe. The buffer is being cleared
without acquiring a lock or setting the uptodate flag, so theoretically,
between the time the buffer's data is cleared and the time it is written
back to the block device using sync_dirty_buffer(), that zero data can be
undone by concurrent block device reads.
Since this buffer points to a location that has been read from disk once,
the uptodate flag will most likely remain, but since it was obtained with
__getblk(), that is not guaranteed. In other words, this is exceptional,
and this function itself is not normally called (only once when mounting
after a specific pattern of unclean shutdown), so it is highly unlikely
that this will actually cause a problem.
Anyway, eliminate this potential race issue by protecting the clearing of
buffer data with a buffer lock and setting the buffer's uptodate flag
within the protected section.
Link: https://lkml.kernel.org/r/20240511002942.9608-1-konishi.ryusuke@gmail.com
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/x86/video/fbdev.c')
0 files changed, 0 insertions, 0 deletions