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[130.117.225.111]) by mx.google.com with ESMTPS id ffacd0b85a97d-48e71ba4841si14877518f8f.88.2026.11.01.15.52.23 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Nov 2026 15:52:23 -0800 (PST) Received-SPF: pass (google.com: domain of mirian.shilakadze@virtuozzo.com designates 130.117.225.111 as permitted sender) client-ip=130.117.225.111; Authentication-Results: mx.google.com; dkim=pass header.i=@virtuozzo.com header.s=relay header.b=ZpxtUZiV; spf=pass (google.com: domain of mirian.shilakadze@virtuozzo.com designates 130.117.225.111 as permitted sender) smtp.mailfrom=mirian.shilakadze@virtuozzo.com; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=virtuozzo.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=MIME-Version:Message-ID:Date:Subject:From: Content-Type; bh=09wlN4SUVtxy9Lx8+vJgtRnVOC15T/5YIKk6OA9VA1M=; b=ZpxtUZiVWhM5 6Vp4EhdMsEc1oyvilRe/f/d5z0HPhYHBF1IQ4624lKTbmCpD9X818sxDTP+H7rEkoTWOLKjXzxM/P BOdpiFM9aC6ySN5JZqM4j67VdGYevHVUoRuPRbS5s4Dn/r+Ojrd+kBHNIZtiYn+wEKcCg8TQQVoml djb2LJYIwdhxBXFvVdq5OzFR//vccqmBWodaqcnKDWpuNCstgc7Xz+QjU7p7Z8Nti4A1/BvP6udqA t1YPuJanePq0Eb+Oucf+MGVn3/Mvw6E3O635oMkDh+j62H0PBwHA+gSaKIl6c9yrZCZ5nftFlKumV 055lbI0l9YQ/JBI1f3uC0A==; Received: from ch-demo-asa.virtuozzo.com ([130.117.225.8] helo=localhost.localdomain) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1xNfHh-004e5A-3A; Mon, 02 Nov 2026 00:52:15 +0100 From: Mirian Shilakadze To: khorenko@virtuozzo.com, ptikhomirov@virtuozzo.com Date: Mon, 2 Nov 2026 03:51:44 +0400 Message-ID: <20261101235155.124059-3-mirian.shilakadze@virtuozzo.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261101235155.124059-1-mirian.shilakadze@virtuozzo.com> References: <20261101235155.124059-1-mirian.shilakadze@virtuozzo.com> MIME-Version: 1.0 X-OZ-Fwd: true Cc: devel@openvz.org Subject: [Devel] [PATCH hci-8.1 2/6] ms/cgroup/dmem: avoid rcu warning when unregister region X-BeenThere: devel@openvz.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: OpenVZ development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: devel-bounces@openvz.org Errors-To: devel-bounces@openvz.org From: Chen Ridong A warnning was detected: WARNING: suspicious RCU usage 6.19.0-rc7-next-20260129+ #1101 Tainted: G O kernel/cgroup/dmem.c:456 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 1 lock held by insmod/532: #0: ffffffff85e78b38 (dmemcg_lock){+.+.}-dmem_cgroup_unregister_region+ stack backtrace: CPU: 2 UID: 0 PID: 532 Comm: insmod Tainted: 6.19.0-rc7-next- Tainted: [O]=OOT_MODULE Call Trace: dump_stack_lvl+0xb0/0xd0 lockdep_rcu_suspicious+0x151/0x1c0 dmem_cgroup_unregister_region+0x1e2/0x380 ? __pfx_dmem_test_init+0x10/0x10 [dmem_uaf] dmem_test_init+0x65/0xff0 [dmem_uaf] do_one_initcall+0xbb/0x3a0 The macro list_for_each_rcu() must be used within an RCU read-side critical section (between rcu_read_lock() and rcu_read_unlock()). Using it outside that context, as seen in dmem_cgroup_unregister_region(), triggers the lockdep warning because the RCU protection is not guaranteed. Replace list_for_each_rcu() with list_for_each_entry_safe(), which is appropriate for traversal under spinlock protection where nodes may be deleted. Fixes: b168ed458dde ("kernel/cgroup: Add "dmem" memory accounting cgroup") Cc: stable@vger.kernel.org # v6.14+ Signed-off-by: Chen Ridong Signed-off-by: Tejun Heo (cherry picked from commit 592a68212c5664bcaa88f24ed80bf791282790fe) https://virtuozzo.atlassian.net/browse/VSTOR-152813 Signed-off-by: Mirian Shilakadze --- kernel/cgroup/dmem.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/cgroup/dmem.c b/kernel/cgroup/dmem.c index eb4e4d3e0922..d71092d2b6ed 100644 --- a/kernel/cgroup/dmem.c +++ b/kernel/cgroup/dmem.c @@ -422,7 +422,7 @@ static void dmemcg_free_region(struct kref *ref) */ void dmem_cgroup_unregister_region(struct dmem_cgroup_region *region) { - struct list_head *entry; + struct dmem_cgroup_pool_state *pool, *next; if (!region) return; @@ -432,10 +432,7 @@ void dmem_cgroup_unregister_region(struct dmem_cgroup_region *region) /* Remove from global region list */ list_del_rcu(®ion->region_node); - list_for_each_rcu(entry, ®ion->pools) { - struct dmem_cgroup_pool_state *pool = - container_of(entry, typeof(*pool), region_node); - + list_for_each_entry_safe(pool, next, ®ion->pools, region_node) { list_del_rcu(&pool->css_node); } -- 2.43.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel