On Wed, Jul 23, 2008 at 10:49:04AM +0000, Johannes Schindelin wrote: > Hi, > > On Wed, 23 Jul 2008, Björn Steinbrink wrote: > > > On 2008.07.23 01:17:45 +0200, Pierre Habouzit wrote: > > > Hi, here is a manual painful down-secting (opposed to a bisect ;P) I > > > did, since git in next cannot fetch on a regular basis for me. The > > > culprit seems to be commit 92392b4: > > > > > > ┌─(1:11)──<~/dev/scm/git 92392b4....>── > > > └[artemis] git fetch > > > remote: Counting objects: 461, done. > > > remote: Compressing objects: 100% (141/141), done. > > > remote: Total 263 (delta 227), reused 155 (delta 121) > > > Receiving objects: 100% (263/263), 95.55 KiB, done. > > > fatal: Out of memory, malloc failed > > > fatal: index-pack failed > > > [2] 16674 abort (core dumped) git fetch > > > > > > ┌─(1:12)──<~/dev/scm/git 92392b4....>── > > > └[artemis] git checkout -m HEAD~1; make git-index-pack > > > Previous HEAD position was 92392b4... index-pack: Honor core.deltaBaseCacheLimit when resolving deltas > > > HEAD is now at 03993e1... index-pack: Track the object_entry that creates each base_data > > > GIT_VERSION = 1.5.6.3.3.g03993 > > > CC index-pack.o > > > LINK git-index-pack > > > > > > ┌─(1:12)──<~/dev/scm/git 03993e1....>── > > > └[artemis] git fetch > > > remote: Counting objects: 461, done. > > > remote: Compressing objects: 100% (141/141), done. > > > remote: Total 263 (delta 227), reused 155 (delta 121) > > > Receiving objects: 100% (263/263), 95.55 KiB, done. > > > Resolving deltas: 100% (227/227), completed with 153 local objects. > > > From git://git.kernel.org/pub/scm/git/git > > > 5ba2c22..0868a30 html -> origin/html > > > 2857e17..abeeabe man -> origin/man > > > 93310a4..95f8ebb master -> origin/master > > > 559998f..e8bf351 next -> origin/next > > > > > > You can see the commit sha's in the prompt. 03993e1 is fine, 92392b4 is > > > broken, I've absolutely no clue about what happens. > > > > > > All I can say is that at some point in get_data_from_pack, obj[1].idx > > > points to something that is *not* a sha so it's probably corrupted. > > > (from index-pack.c). > > > > Here's how to reproduce: > > Funny. That does not reproduce the bug here at all. > > But then, it is unsurprising, since both Pierre and me did something > similar yesterday, fetching _just_ the pre-fetch refs into a freshly > initted Git repository, and then fetching from kernel.org. > > Tested on x86_64. I can reproduce on x86_64 here. And I think I get the problem, and IMHO the pruning thing is flawed. We need more than *one* base to be kept at a time, pruning is too aggressive, and we still keep pointers to actually pruned data. This patch makes the issue non reproducible for me. The rationale is that get_base_data will already prune and is called as often, and in safer places. ================================= diff --git a/index-pack.c b/index-pack.c index ac20a46..5440e43 100644 --- a/index-pack.c +++ b/index-pack.c @@ -245,7 +245,6 @@ static void link_base_data(struct base_data *base, struct base_data *c) c->base = base; c->child = NULL; base_cache_used += c->size; - prune_base_data(c); } static void unlink_base_data(struct base_data *c) ================================= *But* I'm absolutely not sure it's enough. This should be written using reference counting instead of the "retain" hack, and prune should not free() anything that isn't with a 0 reference counter. The current code is brittle, it makes my head explode when I try to understand if the get_base_data() we temporarily keep pointers too may be harmed or not. -- ·O· Pierre Habouzit ··O madcoder@xxxxxxxxxx OOO http://www.madism.org
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