commit bdb6cb9b8b2633c831f532e05cb1780710cde9a8
from: Stefan Sperling <stsp@stsp.name>
date: Tue Mar 07 16:36:45 2023 UTC

fix gotd sometimes reading reused deltas from wrong pack file

The reuse-pack is pinned but may change its cache slot while objects
are being deltified. Refresh the pointer to the pinned reuse-pack before
writing out the pack file, ensuring that reused deltas will in fact be
read from the reuse-pack and not some other pack. Otherwise gotd may send
a broken pack file, or hit an ERR_RANGE condition if the pack file which
now occupies the pinned-pack's old cache slot is shorter. Which can trigger
attempts to read beyond end-of-file which show up in the logs like this:
gotd[37311]: repo_read /var/git/got.git: sending packfile: value out of range
gotd[43877]: uid 1002: value out of range
gotd[43877]: uid 1002: disconnecting

commit - 15aed0533476711f5f9e6c64c1e220f6e960e7fa
commit + bdb6cb9b8b2633c831f532e05cb1780710cde9a8
blob - a467a2aec8f4b84bb79456886304f79f16160ad4
blob + ac4cf855434fedcf1669f57482225399f9486b03
--- lib/pack_create.c
+++ lib/pack_create.c
@@ -1933,6 +1933,9 @@ got_pack_create(uint8_t *packsha1, int packfd, FILE *d
 			goto done;
 	}
 
+	/* Pinned pack may have moved to different cache slot. */
+	reuse_pack = got_repo_get_pinned_pack(repo);
+
 	err = genpack(packsha1, packfd, reuse_pack, delta_cache, deltify.meta,
 	    deltify.nmeta, reuse.meta, reuse.nmeta, ncolored, nfound, ntrees,
 	    nours, repo, force_refdelta, progress_cb, progress_arg, rl,