HE> void inst_list_free(struct inst_list *list) HE> { HE> + if (!list) HE> + return; HE> + HE> free(list->list); HE> inst_list_init(list); HE> } I have no problem with this patch, although I'd like to reiterate that it won't solve the initialization problem. If you have this: struct inst_list foo; inst_list_free(&foo); You're passing in the address of a stack variable, which will never be NULL, so the additional check will fall through. The free() will then attempt to free a garbage pointer (list is valid, but list->list is not) and the heap is blown. I'd also point out that we overwhelmingly use inst_list variables on the stack, which means 99% of the time, this check won't help us, and will just consume "extra cycles". I'm sure that this would eclipse the overhead of a few unnecessary inst_list_init() calls :) I'm fine applying this to handle the case where we might have a dynamically-allocated list pointer. Any objections? -- Dan Smith IBM Linux Technology Center Open Hypervisor Team email: danms@us.ibm.com