We are going to have the following piece of code.
memcg = mem_cgroup_from_id(memcgid)
lruvec = mem_cgroup_zone_lruvec(zone, memcg);
This currently cannot work because mem_cgroup_per_zone_info
allocated and initialized after memcgid become visible:
mem_cgroup_alloc():
idr_replace(&mem_cgroup_idr, memcg, memcg->id);
Move per zone info initialization earlier, before idr_replace().
Same thing was done in upstream commit 0b8f73e1("mm: memcontrol: clean
up alloc, online, offline, free functions") but I don't want
to do full backport, hence this patch.
https://jira.sw.ru/browse/PSBM-91933
Signed-off-by: Andrey Ryabinin <[email protected]>
---
mm/memcontrol.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 052b11501b8e..88e6982c9e17 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6260,6 +6260,7 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
size_t size;
int id;
int i, ret;
+ int node;
size = sizeof(struct mem_cgroup);
size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
@@ -6280,6 +6281,10 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
if (!memcg->stat)
goto out_free;
+ for_each_node(node)
+ if (alloc_mem_cgroup_per_zone_info(memcg, node))
+ goto out_free;
+
for (i = 0; i < MEM_CGROUP_STAT2_NSTATS; i++) {
ret = percpu_counter_init(&memcg->stat2.counters[i], 0,
GFP_KERNEL);
if (ret)
@@ -6296,6 +6301,9 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
free_percpu(memcg->stat);
out_free:
+ for_each_node(node)
+ free_mem_cgroup_per_zone_info(memcg, node);
+
if (memcg->id > 0) {
idr_remove(&mem_cgroup_idr, memcg->id);
synchronize_rcu();
@@ -6385,16 +6393,11 @@ mem_cgroup_css_alloc(struct cgroup *cont)
{
struct mem_cgroup *memcg;
long error = -ENOMEM;
- int node;
memcg = mem_cgroup_alloc();
if (!memcg)
return ERR_PTR(error);
- for_each_node(node)
- if (alloc_mem_cgroup_per_zone_info(memcg, node))
- goto free_out;
-
/* root ? */
if (cont->parent == NULL) {
root_mem_cgroup = memcg;
@@ -6420,10 +6423,6 @@ mem_cgroup_css_alloc(struct cgroup *cont)
#endif
return &memcg->css;
-
-free_out:
- __mem_cgroup_free(memcg);
- return ERR_PTR(error);
}
static int
--
2.19.2
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