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[130.117.225.111]) by mx.google.com with ESMTPS id ffacd0b85a97d-48e71bc8e76si15118956f8f.361.2026.11.01.15.52.21 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 01 Nov 2026 15:52:21 -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=Or0vUtlf; 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=cjRViWdutCX0Gs3cB8srGR7Yc3fYiH7aKybETpIMzwU=; b=Or0vUtlf4+lH FgTN84KTWUoXIqWe1LYw4mI5ar5VCBscTq0nmlhUgcHjgHlGTlatDBqlwM53AcRljSRSB8tz5IzAS IAHq0HkIDF8seYk6A/vOj51Ob7EQ9GpX5t6v6YiZMUV1RBTB0iUgHOxt3Uydy0zHVgNP68dD7Ag3Y FdCOAOCMcE1/53zlJnLer0iDqrlJMvqjAMnxpxdSysyhDACIiIlhLfZ9GaJiSEupXQbXDyOhvDHq9 PZHwAEPmLAE+pNvRdZIxDx+RoB9XuFUahw5wmYXqV42v0P0wIX2l8rXrk/UVvj467nkK8JOBSBzEY z4fdmIFHZ7ks8Q+PQKR1zw==; 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 1xNfHf-004e5A-39; Mon, 02 Nov 2026 00:52:13 +0100 From: Mirian Shilakadze To: khorenko@virtuozzo.com, ptikhomirov@virtuozzo.com Date: Mon, 2 Nov 2026 03:51:43 +0400 Message-ID: <20261101235155.124059-2-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 1/6] ms/cgroup/dmem: fix NULL pointer dereference when setting max 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 An issue was triggered: BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 15 UID: 0 PID: 658 Comm: bash Tainted: 6.19.0-rc6-next-2026012 Tainted: [O]=OOT_MODULE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), RIP: 0010:strcmp+0x10/0x30 RSP: 0018:ffffc900017f7dc0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888107cd4358 RDX: 0000000019f73907 RSI: ffffffff82cc381a RDI: 0000000000000000 RBP: ffff8881016bef0d R08: 000000006c0e7145 R09: 0000000056c0e714 R10: 0000000000000001 R11: ffff888107cd4358 R12: 0007ffffffffffff R13: ffff888101399200 R14: ffff888100fcb360 R15: 0007ffffffffffff CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000105c79000 CR4: 00000000000006f0 Call Trace: dmemcg_limit_write.constprop.0+0x16d/0x390 ? __pfx_set_resource_max+0x10/0x10 kernfs_fop_write_iter+0x14e/0x200 vfs_write+0x367/0x510 ksys_write+0x66/0xe0 do_syscall_64+0x6b/0x390 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f42697e1887 It was trriggered setting max without limitation, the command is like: "echo test/region0 > dmem.max". To fix this issue, add check whether options is valid after parsing the region_name. 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 43151f812886be1855d2cba059f9c93e4729460b) https://virtuozzo.atlassian.net/browse/VSTOR-152813 Signed-off-by: Mirian Shilakadze --- kernel/cgroup/dmem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/cgroup/dmem.c b/kernel/cgroup/dmem.c index 10b63433f057..eb4e4d3e0922 100644 --- a/kernel/cgroup/dmem.c +++ b/kernel/cgroup/dmem.c @@ -699,6 +699,9 @@ static ssize_t dmemcg_limit_write(struct kernfs_open_file *of, if (!region_name[0]) continue; + if (!options || !*options) + return -EINVAL; + rcu_read_lock(); region = dmemcg_get_region_by_name(region_name); rcu_read_unlock(); -- 2.43.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel