[libvirt PATCH] virThreadPoolExpand: Prevent expanding worker pool by zero

`virThreadPoolNewFull` may call `virThreadPoolExpand` with `prioWorkers` = 0. This causes `virThreadPoolExpand` to call `VIR_EXPAND_N` on a null pointer and an increment of zero. The zero increment triggers `virReallocN` to not actually allocate any memory and leave the pointer NULL, which, eventually, causes `memset(NULL, 0, 0)` to be called in `virExpandN`. `memset` is declared `__attribute__ ((__nonnull__ 1))`, which triggers the following warning when libvirt is compiled with address sanitizing enabled: src/util/viralloc.c:82:5: runtime error: null pointer passed as argument 1, which is declared to never be null Signed-off-by: Tim Wiederhake <twiederh(a)redhat.com&gt; --- src/util/virthreadpool.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/util/virthreadpool.c b/src/util/virthreadpool.c index 9ddd86a679..c9d2a17ff4 100644 --- a/src/util/virthreadpool.c +++ b/src/util/virthreadpool.c @@ -179,6 +179,9 @@ virThreadPoolExpand(virThreadPool *pool, size_t gain, bool priority) size_t i = 0; struct virThreadPoolWorkerData *data = NULL; + if (gain == 0) + return 0; + VIR_EXPAND_N(*workers, *curWorkers, gain); for (i = 0; i < gain; i++) { -- 2.31.1