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authorRyusuke Konishi <konishi.ryusuke@gmail.com>2024-05-11 03:29:42 +0300
committerAndrew Morton <akpm@linux-foundation.org>2024-05-20 00:36:21 +0300
commitdb3e24a02e29b507c24c0adb4d22914c65dab763 (patch)
treed2cbd7f222886dd7d159fd9713ebc392cdf7f6f3 /drivers/watchdog/max63xx_wdt.c
parent28d2188709d9c19a7c4601c6870edd9fa0527379 (diff)
downloadlinux-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 'drivers/watchdog/max63xx_wdt.c')
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