On Thu, 17 Jan 2013, Steven Rostedt wrote: > In slab_alloc_node(), after the cpu_slab is assigned, if the task is > preempted and moves to another CPU, there's nothing keeping the page and > object in sync. The -rt kernel crashed because page was NULL and object > was not, and the node_match() dereferences page. Even though the crash > happened on -rt, there's nothing that's keeping this from happening on > mainline. > > The easiest fix is to disable interrupts for the entire time from > acquiring the current CPU cpu_slab and assigning the object and page. > After that, it's fine to allow preemption. Its easiest to just check for the NULL pointer as initally done. The call to __slab_alloc can do what the fastpath does. And the fastpath will verify that the c->page pointer was not changed. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>