Red Hat Knowledgebase

The kernel slab cache is utilized during netdump operations; specifically the skbuff_head_cache and several of the size-XXXX caches, which are usually used for each UPD packet's header and data buffer, and for each incoming netdump request structure. When a target slab cache has no more available objects, access and modification of other unrelated slab caches or the kernel's free page list may result. If the state of these lists is in flux while their memory is being copied to the dumpfile, kmem -[sS] and kmem -[fF] commands will display error messages if they run into kernel bookkeeping inconsistencies associated with the slab caches and the free page lists.