selinux: use __GFP_NOWARN with GFP_NOWAIT in the AVC

In the field, we have seen lots of allocation failure from the call
path below.

06-03 13:29:12.999 1010315 31557 31557 W Binder  : 31542_2: page allocation failure: order:0, mode:0x800(GFP_NOWAIT), nodemask=(null),cpuset=background,mems_allowed=0
...
...
06-03 13:29:12.999 1010315 31557 31557 W Call trace:
06-03 13:29:12.999 1010315 31557 31557 W         : dump_backtrace.cfi_jt+0x0/0x8
06-03 13:29:12.999 1010315 31557 31557 W         : dump_stack+0xc8/0x14c
06-03 13:29:12.999 1010315 31557 31557 W         : warn_alloc+0x158/0x1c8
06-03 13:29:12.999 1010315 31557 31557 W         : __alloc_pages_slowpath+0x9d8/0xb80
06-03 13:29:12.999 1010315 31557 31557 W         : __alloc_pages_nodemask+0x1c4/0x430
06-03 13:29:12.999 1010315 31557 31557 W         : allocate_slab+0xb4/0x390
06-03 13:29:12.999 1010315 31557 31557 W         : ___slab_alloc+0x12c/0x3a4
06-03 13:29:12.999 1010315 31557 31557 W         : kmem_cache_alloc+0x358/0x5e4
06-03 13:29:12.999 1010315 31557 31557 W         : avc_alloc_node+0x30/0x184
06-03 13:29:12.999 1010315 31557 31557 W         : avc_update_node+0x54/0x4f0
06-03 13:29:12.999 1010315 31557 31557 W         : avc_has_extended_perms+0x1a4/0x460
06-03 13:29:12.999 1010315 31557 31557 W         : selinux_file_ioctl+0x320/0x3d0
06-03 13:29:12.999 1010315 31557 31557 W         : __arm64_sys_ioctl+0xec/0x1fc
06-03 13:29:12.999 1010315 31557 31557 W         : el0_svc_common+0xc0/0x24c
06-03 13:29:12.999 1010315 31557 31557 W         : el0_svc+0x28/0x88
06-03 13:29:12.999 1010315 31557 31557 W         : el0_sync_handler+0x8c/0xf0
06-03 13:29:12.999 1010315 31557 31557 W         : el0_sync+0x1a4/0x1c0
..
..
06-03 13:29:12.999 1010315 31557 31557 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:12.999 1010315 31557 31557 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:12.999 1010315 31557 31557 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:12.999 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:12.999 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:12.999 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:12.999 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:12.999 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:12.999 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:12.999 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:12.999 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:12.999 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:13.000 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:13.000 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:13.000 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:13.000 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:13.000 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:13.000 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:13.000 1010161 10686 10686 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:13.000 1010161 10686 10686 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:13.000 1010161 10686 10686 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:13.000 10230 30892 30892 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:13.000 10230 30892 30892 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0
06-03 13:29:13.000 10230 30892 30892 W node 0  : slabs: 57, objs: 2907, free: 0
06-03 13:29:13.000 10230 30892 30892 W SLUB    : Unable to allocate memory on node -1, gfp=0x900(GFP_NOWAIT|__GFP_ZERO)
06-03 13:29:13.000 10230 30892 30892 W cache   : avc_node, object size: 72, buffer size: 80, default order: 0, min order: 0

Based on [1], selinux is tolerate for failure of memory allocation.
Then, use __GFP_NOWARN together.

[1] 476accbe2f6e ("selinux: use GFP_NOWAIT in the AVC kmem_caches")

Signed-off-by: Minchan Kim <minchan@kernel.org>
[PM: subj fix, line wraps, normalized commit refs]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
index c90f45587a0c877b2248b9294daed3c45fc5c0a0..6417ed49661f0461402b094b27c893c79ae30055 100644 (file)
--- a/security/selinux/avc.c
+++ b/security/selinux/avc.c
@@ -297,26 +297,27 @@ 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_NOWAIT);
+       xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep,
+                                    GFP_NOWAIT | __GFP_NOWARN);
        if (!xpd_node)
                return NULL;
 
        xpd = &xpd_node->xpd;
        if (which & XPERMS_ALLOWED) {
                xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep,
-                                               GFP_NOWAIT);
+                                               GFP_NOWAIT | __GFP_NOWARN);
                if (!xpd->allowed)
                        goto error;
        }
        if (which & XPERMS_AUDITALLOW) {
                xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep,
-                                               GFP_NOWAIT);
+                                               GFP_NOWAIT | __GFP_NOWARN);
                if (!xpd->auditallow)
                        goto error;
        }
        if (which & XPERMS_DONTAUDIT) {
                xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep,
-                                               GFP_NOWAIT);
+                                               GFP_NOWAIT | __GFP_NOWARN);
                if (!xpd->dontaudit)
                        goto error;
        }
@@ -344,7 +345,7 @@ static struct avc_xperms_node *avc_xperms_alloc(void)
 {
        struct avc_xperms_node *xp_node;
 
-       xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT);
+       xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT | __GFP_NOWARN);
        if (!xp_node)
                return xp_node;
        INIT_LIST_HEAD(&xp_node->xpd_head);
@@ -500,7 +501,7 @@ static struct avc_node *avc_alloc_node(struct selinux_avc *avc)
 {
        struct avc_node *node;
 
-       node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT);
+       node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT | __GFP_NOWARN);
        if (!node)
                goto out;