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

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
...@@ -498,7 +498,9 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) ...@@ -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 * The node we allocated has no zone fallback lists. For avoiding
* to access not-initialized zonelist, build here. * to access not-initialized zonelist, build here.
*/ */
mutex_lock(&zonelists_mutex);
build_all_zonelists(NULL); build_all_zonelists(NULL);
mutex_unlock(&zonelists_mutex);
return pgdat; return pgdat;
} }
......
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