[RH7] memcg: account security cred as well to kmemcg

Submitted by Vasily Averin on Sept. 26, 2020, 9:48 a.m.


Message ID eb4da797-c55c-9aed-0590-c90d8cb4fbdb@virtuozzo.com
State New
Series "memcg: account security cred as well to kmemcg"
Headers show

Commit Message

Vasily Averin Sept. 26, 2020, 9:48 a.m.
From: Shakeel Butt <shakeelb@google.com>

The cred_jar kmem_cache is already memcg: accounted in the current kernel
but cred->security is not.  Account cred->security to kmemcg.

Recently we saw high root slab usage on our production and on further
inspection, we found a buggy application leaking processes.  Though that
buggy application was contained within its memcg but we observe much
more system memory overhead, couple of GiBs, during that period.  This
overhead can adversely impact the isolation on the system.

One source of high overhead we found was cred->security objects, which
have a lifetime of at least the life of the process which allocated

Link: http://lkml.kernel.org/r/20191205223721.40034-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Chris Down <chris@chrisdown.name>
Reviewed-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

(chrry-picked upstream commit 84029fd04c201a4c7e0b07ba262664900f47c6f5)

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
 kernel/cred.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Patch hide | download patch | download mbox

diff --git a/kernel/cred.c b/kernel/cred.c
index f6bd635535fa..0984a289204b 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -209,7 +209,7 @@  struct cred *cred_alloc_blank(void)
 	new->magic = CRED_MAGIC;
-	if (security_cred_alloc_blank(new, GFP_KERNEL) < 0)
+	if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;
 	return new;
@@ -267,7 +267,7 @@  struct cred *prepare_creds(void)
 	new->security = NULL;
-	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;
 	return new;
@@ -620,7 +620,7 @@  struct cred *prepare_kernel_cred(struct task_struct *daemon)
 	new->security = NULL;
-	if (security_prepare_creds(new, old, GFP_KERNEL) < 0)
+	if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0)
 		goto error;