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memcg: account security cred as well to kmemcg 

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 <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>
This commit is contained in:
Shakeel Butt 2020-01-04 12:59:43 -08:00 committed by Linus Torvalds
parent a69b83e1ae
commit 84029fd04c
1 changed files with 3 additions and 3 deletions
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6
kernel/cred.c
View File

@ -223,7 +223,7 @@ 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;
@ -282,7 +282,7 @@ 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;
@ -715,7 +715,7 @@ 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);