On 08/26/2015 05:56 PM, Dave Chinner wrote:
On Wed, Aug 26, 2015 at 05:29:55PM -0500, rjohnston@xxxxxxx wrote:
The call to memset will segfault because the offset for the first
parameter is done twice. We are using pointer math to do the
calculation.
The first time is when calculating oldsize, the size of i2gseg_t
is accounted for.
oldsize = (numsegs - SEGPERHNK) * sizeof(i2gseg_t);
Then in the call to memset, oldsize is again multiplied by the size
of i2gmap_t.
memset(inomap.i2gmap + oldsize, ...)
i2gmap holds the used inodes in each chunk. When there are 2^31 chunk
entries, it could describe 2^31 (1 inode/chunk)- 2^40 (64 inodes/chunk).
With 100s of millions of inodes there are enough entries to wrap the
32 bit variable oldsize.
Adding a bounds check (numsegs < 0) and switching to use array
index notation instead of calculating the pointer address twice
would resolve this issue. The unneeded local variable oldsize
can be removed as well.
Can't believe I missed this first two times time through - the patch
is missing your signed-off-by. Just reply with it, and I'll fix it
up on commit. :)
Dooh my bad
Signed-off-by: Rich Johnston <rjohnston@xxxxxxx>
Thanks, Rich!
Cheers,
Dave.
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