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[130.117.225.111]) by mx.google.com with ESMTPS id ffacd0b85a97d-48fe9ea08c5si5800917f8f.18.2026.11.04.12.08.43 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Nov 2026 12:08:43 -0800 (PST) Received-SPF: pass (google.com: domain of khorenko@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=kSUzYnPD; spf=pass (google.com: domain of khorenko@virtuozzo.com designates 130.117.225.111 as permitted sender) smtp.mailfrom=khorenko@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=Message-Id:Date:From:Subject:Content-Type: MIME-Version; bh=mT3xPXP7DI+mH4BWGqbu4sR/ZrN/sSKRFWPDyhy8ZAU=; b=kSUzYnPDa6Mn U/UZ5s47K9eeUy0/vZfomrVvvhugvBuzwiqAG2fm2f0KJtXfAQrvCKC188EGnN1x8MDCdqEkfJQFB ELcHWKE3wjh8lBK7XWbp4AGS4fi00q2y+AwbTpFrxV+8tF5AIRjIw741QZXzEp3WMW8kNmRrhqERA 5RxiFa9Fu1WlRJACOKsllaK5Jf5nP/G6qf7kQTG1J2OZII5v4zPi8XY5eBzO4P5QfETHzw5ZLaANi mrPJXgdaOD3KhjW2B98Qb8nkgyabxRBdhl7tOvaE18BPf1wrmg6ZZvkkGJjAAQ4O5RGdtg2Qx3u22 Fdsyja5qr/sJjn1b9o+9dQ==; Received: from ch-demo-asa.virtuozzo.com ([130.117.225.8] helo=f0.sw.ru) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1xOhDq-000aSY-07; Wed, 04 Nov 2026 21:08:42 +0100 MIME-Version: 1.0 From: Konstantin Khorenko To: Andrey Drobyshev In-Reply-To: <20261030144933.944360-3-andrey.drobyshev@virtuozzo.com> References: <20261030144933.944360-1-andrey.drobyshev@virtuozzo.com> <20261030144933.944360-3-andrey.drobyshev@virtuozzo.com> Date: Wed, 04 Nov 2026 21:08:34 +0100 Message-Id: <179382291494.2764784.15864758999065794442.b4-review@b4> X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1615; i=khorenko@virtuozzo.com; h=from:subject:message-id; bh=zCESE0S05Fv6LQ4OONGETg1NnkhlxdHgegJ5LjAIG24=; b=owEBbQKS/ZANAwAKAVGWCkf5YVwqAcsmYgBq65DK76NYjc8c8i92FbCGoexMOE7MXbpI6JbLs 4IYWEIK+piJAjMEAAEKAB0WIQRWD23IPcXT0GO9CCxRlgpH+WFcKgUCauuQygAKCRBRlgpH+WFc KphDEACkfOgFdJE2pHFhUeKu7zjONAkGURy/OxV0iIIbgR4u9BsUBMQoXLpD2wV3H6Yx6xX44n6 dLyRbjzXf97F23oW1ge7I/NmvT8cx/w1mRfqq9PUIbNBqa7m3Gx+M6RlMjgJL2g9LnaKwQQbpg3 5IZTOso84M49vZmVVSDkGputxvQhVwXAhW2qgIeCIWmUgXjnLYpp2JdhXkvoM4S6NOSNamkD1tS P6CEmH0yP6kgW3rmoNnHeERzhwrzSmAmeQ0VdR6PUTzhKnZgRG0EZpUTVLG5piYQbQyffW/v6zX clzxi9gBVOYJ3VpxXja/ntNheYfMJzJhRzfBRqn1zUDwlcfbxXxPZOUH8IyhCU5Cyy2FJiatKSx J+/Q0MPMhZLEXW7mJHm3Wl3PX6mTd8VmBPVnXs33+HEOu1tulg0lqOq2YIlH2IuJPmE24orqIpi 6u0KfgFXLzv4jdkTEWqX0fDVaQifbFUBWktCAIFMZOR+zGuWrlxG24246pTLRpwRoHTU/jHCqMl WjhbagzkGIEsY5WlijB4iohPj46yIS//P69D4rp8i/UxWTLYF+sguuvJZYxnfga3bah26tnOd4y IZhksm1+rF2ZnvZndXCHDdhRTXTpCrnL2mV8FNrjRXSHftGzWWtEuWhQhrKwMiRQ3FvGtqHKGIP 9PNzjr9aLrzge8Q== X-Developer-Key: i=khorenko@virtuozzo.com; a=openpgp; fpr=560F6DC83DC5D3D063BD082C51960A47F9615C2A X-OZ-Fwd: true Cc: devel@openvz.org Subject: Re: [Devel] [PATCH hci-8.1 2/2] KVM: remove the VM's debugfs directory when its fd is released 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 I won't apply this version, please send v2 with the changes below. On Fri, 30 Oct 2026 16:49:33 +0200, Andrey Drobyshev wrote: > + /* The directory is named after this fd, which is free to reuse now */ > + kvm_destroy_vm_debugfs(kvm); Item 4 of the cover letter reply: at fd release remove only the directory. Keep freeing debugfs_stat_data in kvm_destroy_vm(), moved out from under the IS_ERR(kvm->debugfs_dentry) early return. Why: an open stats file holds a reference to the kvm, not to its stat data. kvm_debugfs_release() reads inode->i_private, the stat data, to find the kvm it has to put, and debugfs calls it even after the file was removed. Before this patch the stat data lived as long as the kvm, so that was safe. Now it is freed at fd release: open /sys/kernel/debug/kvm/-/exits, let QEMU exit, close the file, and the release reads freed memory and puts whatever kvm pointer it finds there. This hits any VM shutdown that races with a stats reader, not only a live update. > + kvm->debugfs_dentry = ERR_PTR(-ENOENT); Item 5 of the cover letter reply: say in the message that the destroy uevent no longer carries STATS_PATH, and that the stats go away for a VM that keeps running on its vcpu fds after the VM fd is closed. Why: kvm_destroy_vm() sends the destroy uevent, and the uevent adds STATS_PATH only for a valid dentry. Both changes look acceptable, but a reader of the message should know about them. Item 6 of the cover letter reply: single space after a period, and the Feature: line. -- Konstantin Khorenko, Virtuozzo Linux Kernel Team _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel