From abb59358f1c4d9490688ef7e133afcb6b5bcb7ca Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Sat, 4 Jan 2020 12:59:43 -0800 Subject: [PATCH] memcg: account security cred as well to kmemcg commit 84029fd04c201a4c7e0b07ba262664900f47c6f5 upstream. 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 them. Link: http://lkml.kernel.org/r/20191205223721.40034-1-shakeelb@google.com Signed-off-by: Shakeel Butt Acked-by: Chris Down Reviewed-by: Roman Gushchin Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- kernel/cred.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/cred.c b/kernel/cred.c index 5ab1f7ec946e..a9f0f8b21d8c 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -220,7 +220,7 @@ struct cred *cred_alloc_blank(void) new->magic = CRED_MAGIC; #endif - if (security_cred_alloc_blank(new, GFP_KERNEL) < 0) + if (security_cred_alloc_blank(new, GFP_KERNEL_ACCOUNT) < 0) goto error; return new; @@ -279,7 +279,7 @@ struct cred *prepare_creds(void) new->security = NULL; #endif - if (security_prepare_creds(new, old, GFP_KERNEL) < 0) + if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) goto error; validate_creds(new); return new; @@ -654,7 +654,7 @@ struct cred *prepare_kernel_cred(struct task_struct *daemon) #ifdef CONFIG_SECURITY new->security = NULL; #endif - if (security_prepare_creds(new, old, GFP_KERNEL) < 0) + if (security_prepare_creds(new, old, GFP_KERNEL_ACCOUNT) < 0) goto error; put_cred(old);