From: Jeff King <peff@peff.net>
To: "Dale R. Worley" <worley@alum.mit.edu>
Cc: git@vger.kernel.org
Subject: Re: "git fsck" fails on malloc of 80 G
Date: Wed, 18 Dec 2013 17:09:23 -0500 [thread overview]
Message-ID: <20131218220922.GA16347@sigill.intra.peff.net> (raw)
In-Reply-To: <201312182108.rBIL8lAo015570@hobgoblin.ariadne.com>
On Wed, Dec 18, 2013 at 04:08:47PM -0500, Dale R. Worley wrote:
> > From: Jeff King <peff@peff.net>
>
> > One of the problems I ran into recently is that
> > corrupt data can cause it to make a large allocation
>
> One thing I notice is that in unpack_compressed_entry() in
> sha1_file.c, there is a mallocz of "size" bytes. It appears that
> "size" is the size of the object that is being unpacked. If so, this
> code cannot be correct, because it assumes that any file that is
> stored in the repository can be put into a buffer allocated in RAM.
For some definition of correct. Git does load whole-blobs into memory in
several places. Some code paths _can_ stream, but they do not stream
deltas, and the diff engine definitely wants the whole thing in-core.
So you are reading it right. If you want to work on changing it, be my
guest, but it's a non-trivial fix. ;)
-Peff
prev parent reply other threads:[~2013-12-18 22:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-16 16:05 "git fsck" fails on malloc of 80 G Dale R. Worley
2013-12-16 19:15 ` Jeff King
2013-12-18 3:06 ` Dale R. Worley
2013-12-18 21:58 ` Jeff King
2013-12-18 21:08 ` Dale R. Worley
2013-12-18 22:09 ` Jeff King [this message]
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