diff options
| -rw-r--r-- | agent/cache.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/agent/cache.c b/agent/cache.c index f58eaeaaa..248368277 100644 --- a/agent/cache.c +++ b/agent/cache.c @@ -475,6 +475,19 @@ agent_get_cache (const char *key, cache_mode_t cache_mode) void agent_store_cache_hit (const char *key) { - xfree (last_stored_cache_key); - last_stored_cache_key = key? xtrystrdup (key) : NULL; + char *new; + char *old; + + /* To make sure the update is atomic under the non-preemptive thread + * model, we must make sure not to surrender control to a different + * thread. Therefore, we avoid calling the allocator during the + * update. */ + new = key ? xtrystrdup (key) : NULL; + + /* Atomic update. */ + old = last_stored_cache_key; + last_stored_cache_key = new; + /* Done. */ + + xfree (old); } |