[PATCH for-4.9.y 11/14] selinux: use GFP_NOWAIT in the AVC kmem_caches
From: Amit Pundir <hidden>
Date: 2018-08-29 00:07:19
Subsystem:
selinux security module, the rest · Maintainers:
Paul Moore, Stephen Smalley, Linus Torvalds
From: Michal Hocko <mhocko@kernel.org> commit 476accbe2f6ef69caeebe99f52a286e12ac35aee upstream. There is a strange __GFP_NOMEMALLOC usage pattern in SELinux, specifically GFP_ATOMIC | __GFP_NOMEMALLOC which doesn't make much sense. GFP_ATOMIC on its own allows to access memory reserves while __GFP_NOMEMALLOC dictates we cannot use memory reserves. Replace this with the much more sane GFP_NOWAIT in the AVC code as we can tolerate memory allocation failures in that code. Signed-off-by: Michal Hocko <mhocko@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Amit Pundir <redacted> --- To be applied on 4.4.y as well. Build tested on v4.4.153. security/selinux/avc.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index e60c79de13e1..52f3c550abcc 100644
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c@@ -348,27 +348,26 @@ static struct avc_xperms_decision_node struct avc_xperms_decision_node *xpd_node; struct extended_perms_decision *xpd; - xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, - GFP_ATOMIC | __GFP_NOMEMALLOC); + xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, GFP_NOWAIT); if (!xpd_node) return NULL; xpd = &xpd_node->xpd; if (which & XPERMS_ALLOWED) { xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep, - GFP_ATOMIC | __GFP_NOMEMALLOC); + GFP_NOWAIT); if (!xpd->allowed) goto error; } if (which & XPERMS_AUDITALLOW) { xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep, - GFP_ATOMIC | __GFP_NOMEMALLOC); + GFP_NOWAIT); if (!xpd->auditallow) goto error; } if (which & XPERMS_DONTAUDIT) { xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep, - GFP_ATOMIC | __GFP_NOMEMALLOC); + GFP_NOWAIT); if (!xpd->dontaudit) goto error; }
@@ -396,8 +395,7 @@ static struct avc_xperms_node *avc_xperms_alloc(void) { struct avc_xperms_node *xp_node; - xp_node = kmem_cache_zalloc(avc_xperms_cachep, - GFP_ATOMIC|__GFP_NOMEMALLOC); + xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT); if (!xp_node) return xp_node; INIT_LIST_HEAD(&xp_node->xpd_head);
@@ -550,7 +548,7 @@ static struct avc_node *avc_alloc_node(void) { struct avc_node *node; - node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC|__GFP_NOMEMALLOC); + node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT); if (!node) goto out;
--
2.7.4