2.6.37-stable review patch. If anyone has any objections, please let us know.
------------------ From: Christoph Lameter <[email protected]> commit 04d94879c8a4973b5499dc26b9d38acee8928791 upstream. The purpose of the locking is to prevent removal and additions of nodes when statistics are gathered for a slab cache. So we need to avoid racing with memory hotplug functionality. It is enough to take the memory hotplug locks there instead of the slub_lock. online_pages() currently does not acquire the memory_hotplug lock. Another patch will be submitted by the memory hotplug authors to take the memory hotplug lock and describe the uses of the memory hotplug lock to protect against adding and removal of nodes from non hotplug data structures. Reported-and-tested-by: Bart Van Assche <[email protected]> Acked-by: David Rientjes <[email protected]> Signed-off-by: Christoph Lameter <[email protected]> Signed-off-by: Pekka Enberg <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- mm/slub.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/mm/slub.c +++ b/mm/slub.c @@ -3821,7 +3821,7 @@ static ssize_t show_slab_objects(struct } } - down_read(&slub_lock); + lock_memory_hotplug(); #ifdef CONFIG_SLUB_DEBUG if (flags & SO_ALL) { for_each_node_state(node, N_NORMAL_MEMORY) { @@ -3862,7 +3862,7 @@ static ssize_t show_slab_objects(struct x += sprintf(buf + x, " N%d=%lu", node, nodes[node]); #endif - up_read(&slub_lock); + unlock_memory_hotplug(); kfree(nodes); return x + sprintf(buf + x, "\n"); } _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
