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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> |
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.. | ||
alloc.c | ||
alloc.h | ||
bmap.c | ||
bmap.h | ||
btnode.c | ||
btnode.h | ||
btree.c | ||
btree.h | ||
cpfile.c | ||
cpfile.h | ||
dat.c | ||
dat.h | ||
dir.c | ||
direct.c | ||
direct.h | ||
export.h | ||
file.c | ||
gcinode.c | ||
ifile.c | ||
ifile.h | ||
inode.c | ||
ioctl.c | ||
Kconfig | ||
Makefile | ||
mdt.c | ||
mdt.h | ||
namei.c | ||
nilfs.h | ||
page.c | ||
page.h | ||
recovery.c | ||
segbuf.c | ||
segbuf.h | ||
segment.c | ||
segment.h | ||
sufile.c | ||
sufile.h | ||
super.c | ||
sysfs.c | ||
sysfs.h | ||
the_nilfs.c | ||
the_nilfs.h |