linux-kernel - [PATCH v5 5/6] percpu: scoped objcg protection

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231019225346.1822282-6-roman.gushchin@linux.dev>
Date:   Thu, 19 Oct 2023 15:53:45 -0700
From:   Roman Gushchin <roman.gushchin@...ux.dev>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
        Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...nel.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Muchun Song <muchun.song@...ux.dev>,
        Dennis Zhou <dennis@...nel.org>,
        David Rientjes <rientjes@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Naresh Kamboju <naresh.kamboju@...aro.org>,
        Roman Gushchin <roman.gushchin@...ux.dev>
Subject: [PATCH v5 5/6] percpu: scoped objcg protection

Similar to slab and kmem, switch to a scope-based protection of the
objcg pointer to avoid.

Signed-off-by: Roman Gushchin (Cruise) <roman.gushchin@...ux.dev>
Tested-by: Naresh Kamboju <naresh.kamboju@...aro.org>
Acked-by: Shakeel Butt <shakeelb@...gle.com>
Reviewed-by: Vlastimil Babka <vbabka@...e.cz>
---
 mm/percpu.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index a7665de8485f..f53ba692d67a 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1628,14 +1628,12 @@ static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp,
 	if (!memcg_kmem_online() || !(gfp & __GFP_ACCOUNT))
 		return true;
 
-	objcg = get_obj_cgroup_from_current();
+	objcg = current_obj_cgroup();
 	if (!objcg)
 		return true;
 
-	if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size))) {
-		obj_cgroup_put(objcg);
+	if (obj_cgroup_charge(objcg, gfp, pcpu_obj_full_size(size)))
 		return false;
-	}
 
 	*objcgp = objcg;
 	return true;
@@ -1649,6 +1647,7 @@ static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
 		return;
 
 	if (likely(chunk && chunk->obj_cgroups)) {
+		obj_cgroup_get(objcg);
 		chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg;
 
 		rcu_read_lock();
@@ -1657,7 +1656,6 @@ static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
 		rcu_read_unlock();
 	} else {
 		obj_cgroup_uncharge(objcg, pcpu_obj_full_size(size));
-		obj_cgroup_put(objcg);
 	}
 }
 
-- 
2.42.0