mm/memory_hotplug.c: prevent memory leak when reusing pgdat

When offlining a node in try_offline_node(), pgdat is not released.  So
that pgdat could be reused in hotadd_new_pgdat().  While we reallocate
pgdat->per_cpu_nodestats if this pgdat is reused.

This patch prevents the memory leak by just allocating per_cpu_nodestats
when it is a new pgdat.

Link: http://lkml.kernel.org/r/20190813020608.10194-1-richardw.yang@linux.intel.com
Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <OSalvador@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wei Yang 2019-09-23 15:35:52 -07:00 committed by Linus Torvalds
parent b6c88d3b9d
commit 33fce0113d

View File

@ -925,8 +925,11 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
if (!pgdat)
return NULL;
pgdat->per_cpu_nodestats =
alloc_percpu(struct per_cpu_nodestat);
arch_refresh_nodedata(nid, pgdat);
} else {
int cpu;
/*
* Reset the nr_zones, order and classzone_idx before reuse.
* Note that kswapd will init kswapd_classzone_idx properly
@ -935,6 +938,12 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
pgdat->nr_zones = 0;
pgdat->kswapd_order = 0;
pgdat->kswapd_classzone_idx = 0;
for_each_online_cpu(cpu) {
struct per_cpu_nodestat *p;
p = per_cpu_ptr(pgdat->per_cpu_nodestats, cpu);
memset(p, 0, sizeof(*p));
}
}
/* we can use NODE_DATA(nid) from here */
@ -944,7 +953,6 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start)
/* init node's zones as empty zones, we don't have any present pages.*/
free_area_init_core_hotplug(nid);
pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat);
/*
* The node we allocated has no zone fallback lists. For avoiding