All of lore.kernel.org
 help / color / mirror / Atom feed
From: Muchun Song <songmuchun@bytedance.com>
To: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com,
	akpm@linux-foundation.org, shakeelb@google.com, guro@fb.com,
	iamjoonsoo.kim@lge.com, laoar.shao@gmail.com,
	chris@chrisdown.name, christian.brauner@ubuntu.com,
	peterz@infradead.org, mingo@kernel.org, keescook@chromium.org,
	tglx@linutronix.de, esyr@redhat.com, surenb@google.com,
	areber@redhat.com, elver@google.com
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-mm@kvack.org, Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH 2/5] mm: memcg/slab: Fix use after free in obj_cgroup_charge
Date: Tue, 27 Oct 2020 16:02:53 +0800	[thread overview]
Message-ID: <20201027080256.76497-3-songmuchun@bytedance.com> (raw)
In-Reply-To: <20201027080256.76497-1-songmuchun@bytedance.com>

The rcu_read_lock/unlock only can guarantee that the memcg will
not be freed, but it cannot guarantee the success of css_get to
memcg. This can be happened when we reparent the memcg. So using
css_tryget instead of css_get.

Fixes: bf4f059954dc ("mm: memcg/slab: obj_cgroup API")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
 mm/memcontrol.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index fcbd79c5023e..c0c27bee23ad 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3223,8 +3223,10 @@ int obj_cgroup_charge(struct obj_cgroup *objcg, gfp_t gfp, size_t size)
 	 * independently later.
 	 */
 	rcu_read_lock();
+retry:
 	memcg = obj_cgroup_memcg(objcg);
-	css_get(&memcg->css);
+	if (!css_tryget(&memcg->css))
+		goto retry;
 	rcu_read_unlock();
 
 	nr_pages = size >> PAGE_SHIFT;
-- 
2.20.1


  parent reply	other threads:[~2020-10-27  8:07 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-27  8:02 [PATCH 0/5] Fix some bugs in memcg/slab Muchun Song
2020-10-27  8:02 ` Muchun Song
2020-10-27  8:02 ` [PATCH 1/5] mm: memcg/slab: Fix return child memcg objcg for root memcg Muchun Song
2020-10-27 17:42   ` Roman Gushchin
2020-10-27 17:42     ` Roman Gushchin
2020-10-27 19:05     ` Roman Gushchin
2020-10-27 19:05       ` Roman Gushchin
2020-10-27  8:02 ` Muchun Song [this message]
2020-10-27 18:31   ` [PATCH 2/5] mm: memcg/slab: Fix use after free in obj_cgroup_charge Roman Gushchin
2020-10-27 18:31     ` Roman Gushchin
2020-10-27  8:02 ` [PATCH 3/5] mm: memcg/slab: Rename *_lruvec_slab_state to *_lruvec_kmem_state Muchun Song
2020-10-27  8:02   ` Muchun Song
2020-10-27 18:37   ` Roman Gushchin
2020-10-27 18:37     ` Roman Gushchin
2020-10-27  8:02 ` [PATCH 4/5] mm: memcg/slab: Fix root memcg vmstats Muchun Song
2020-10-27  8:02   ` Muchun Song
2020-10-27 18:48   ` Roman Gushchin
2020-10-27 18:48     ` Roman Gushchin
2020-10-28  2:56     ` [External] " Muchun Song
2020-10-28  2:56       ` Muchun Song
2020-10-28  2:56       ` Muchun Song
2020-10-28  3:47       ` Muchun Song
2020-10-28  3:47         ` Muchun Song
2020-10-29  0:14       ` Roman Gushchin
2020-10-29  0:14         ` Roman Gushchin
2020-10-29  6:15         ` Muchun Song
2020-10-29  6:15           ` Muchun Song
2020-11-10  1:32           ` Roman Gushchin
2020-11-10  1:32             ` Roman Gushchin
2020-11-10  2:57             ` Muchun Song
2020-11-10  2:57               ` Muchun Song
2020-11-10  2:57               ` Muchun Song
2020-10-27  8:02 ` [PATCH 5/5] mm: memcontrol: Simplify the mem_cgroup_page_lruvec Muchun Song
2020-10-27  8:02   ` Muchun Song
2020-10-27 13:36   ` Michal Hocko
2020-10-27 13:36     ` Michal Hocko
2020-10-27 14:15     ` [External] " Muchun Song
2020-10-27 14:15       ` Muchun Song
2020-10-27 14:15       ` Muchun Song
2020-10-27 14:31       ` Michal Hocko
2020-10-27 14:31         ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201027080256.76497-3-songmuchun@bytedance.com \
    --to=songmuchun@bytedance.com \
    --cc=akpm@linux-foundation.org \
    --cc=areber@redhat.com \
    --cc=cgroups@vger.kernel.org \
    --cc=chris@chrisdown.name \
    --cc=christian.brauner@ubuntu.com \
    --cc=elver@google.com \
    --cc=esyr@redhat.com \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=iamjoonsoo.kim@lge.com \
    --cc=keescook@chromium.org \
    --cc=laoar.shao@gmail.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=mingo@kernel.org \
    --cc=peterz@infradead.org \
    --cc=shakeelb@google.com \
    --cc=surenb@google.com \
    --cc=tglx@linutronix.de \
    --cc=vdavydov.dev@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.