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Commit f957db4f authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

mm, hotplug: protect zonelist building with zonelists_mutex 



Commit 959ecc48 ("mm/memory_hotplug.c: fix building of node hotplug
zonelist") does not protect the build_all_zonelists() call with
zonelists_mutex as needed.  This can lead to races in constructing
zonelist ordering if a concurrent build is underway.  Protecting this
with lock_memory_hotplug() is insufficient since zonelists can be
rebuild though sysfs as well.

Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7553e8f2

mm/memory_hotplug.c

+2 −0
Original line number Diff line number Diff line
@@ -498,7 +498,9 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) 
	 * The node we allocated has no zone fallback lists. For avoiding

	 * to access not-initialized zonelist, build here.

	 */

	mutex_lock(&zonelists_mutex);

	build_all_zonelists(NULL);

	mutex_unlock(&zonelists_mutex);



	return pgdat;

}