Hi Peter, It's not for memoryless node, but to solve a race window in CPU hot-addition. The related CPU hot-addition flow is: 1) Handle CPU hot-addition event 1.a) gather platform specific information 1.b) associate hot-added CPU with a node 1.c) create CPU device 2) User online hot-added CPUs through sysfs: 2.a) cpu_up() 2.b) ->try_online_node() 2.c) ->hotadd_new_pgdat() 2.d) ->node_set_online()
So between 1.b and 2.c, kmalloc_node(nid) may cause invalid memory access without the node_online(nid) check. Best Regards! Gerry On 2014/4/22 16:15, Peter Zijlstra wrote: > On Tue, Apr 22, 2014 at 01:27:15PM +0800, Jiang Liu wrote: >> When calling kzalloc_node(size, flags, node), we should first check >> whether node is onlined, otherwise it may cause invalid memory access >> as below. > > But this is only for memory less node crap, right? > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/