In the case that a cpu is taken offline before zcache_do_preload() is
ever called on the cpu, the per-cpu zcache_preloads structure will
be uninitialized. In the CPU_DEAD case for zcache_cpu_notifier(),
kp->obj is not checked before calling kmem_cache_free() on it.
If it is NULL, a crash results.
This patch ensures that both kp->obj and kp->page are not NULL before
calling the respective free functions. In practice, just checking
one or the other should be sufficient since they are assigned together
in zcache_do_preload(), but I check both for safety.
Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
kp->objnodes[kp->nr - 1] = NULL;
kp->nr--;
}
- kmem_cache_free(zcache_obj_cache, kp->obj);
- free_page((unsigned long)kp->page);
+ if (kp->obj) {
+ kmem_cache_free(zcache_obj_cache, kp->obj);
+ kp->obj = NULL;
+ }
+ if (kp->page) {
+ free_page((unsigned long)kp->page);
+ kp->page = NULL;
+ }
break;
default:
break;