Re: [RFH] index_name_exists() conversion

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Feb 21, 2008, 17:00 UTC
Message-ID: <alpine.LFD.1.00.0802210816380.7833@woody.linux-foundation.org>
In-Reply-To: <alpine.LFD.1.00.0802210806540.7833@woody.linux-foundation.org>

On Thu, 21 Feb 2008, Linus Torvalds wrote:

> 
> (Also, some code used to just reuse the same cache entry multiple times, 
> and that got illegal for the same reason).

Ahh. I think I may have found it.

It's stupid.

In hash_index_entry(), we insert the entry into the name hash, but if it got inserted as the first entry, we don't actually set the ->next pointer to NULL.

So the chain would end up pointing to some random crud. I think we were just lucky with our allocators generally filling those things with zero.

See if this fixes it.

		Linus

---

diff --git a/read-cache.c b/read-cache.c
--- a/read-cache.c
+++ b/read-cache.c
@@ -39,6 +39,7 @@ static void hash_index_entry(struct index_state *istate, struct cache_entry *ce)
 	void **pos;
 	unsigned int hash = hash_name(ce->name, ce_namelen(ce));
 
+	ce->next = NULL;
 	pos = insert_hash(hash, ce, &istate->name_hash);
 	if (pos) {
 		ce->next = *pos;