It was reported [1] that Git started to fail with an out-of-memory error
when initializing repositories with the reftable backend on NonStop
platforms. A bisect led to 802c0646ac (reftable/merged: handle
allocation failures in `merged_table_init_iter()`, 2024-10-02), which
changed how we allocate memory when initializing a merged table.
The root cause of this seems to be that NonStop returns a `NULL` pointer
when doing a zero-sized allocation. This would've already happened
before the above change, but we never noticed because we did not check
the result. Now we do notice and thus return an out-of-memory error to
the caller.
Fix the issue by skipping the allocation altogether in case there are no
readers.
[1]: <00ad01db5017$aa9ce340$ffd6a9c0$@nexbridge.com>
Reported-by: Randall S. Becker <rsbecker@xxxxxxxxxxxxx>
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
reftable/merged.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/reftable/merged.c b/reftable/merged.c
index bb0836e3443271f9c0d5ba5582c78694d437ddc2..e72b39e178d4dec6ddfca970b5af71b71431397a 100644
--- a/reftable/merged.c
+++ b/reftable/merged.c
@@ -240,14 +240,16 @@ int merged_table_init_iter(struct reftable_merged_table *mt,
struct reftable_iterator *it,
uint8_t typ)
{
- struct merged_subiter *subiters;
+ struct merged_subiter *subiters = NULL;
struct merged_iter *mi = NULL;
int ret;
- REFTABLE_CALLOC_ARRAY(subiters, mt->readers_len);
- if (!subiters) {
- ret = REFTABLE_OUT_OF_MEMORY_ERROR;
- goto out;
+ if (mt->readers_len) {
+ REFTABLE_CALLOC_ARRAY(subiters, mt->readers_len);
+ if (!subiters) {
+ ret = REFTABLE_OUT_OF_MEMORY_ERROR;
+ goto out;
+ }
}
for (size_t i = 0; i < mt->readers_len; i++) {
--
2.48.0.rc0.184.g0fc57dec57.dirty
