From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D464DC88E4A for ; Fri, 11 Sep 2026 10:53:07 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1x4ysN-000304-Cz; Fri, 11 Sep 2026 06:52:59 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x4ysL-0002zk-Ev; Fri, 11 Sep 2026 06:52:57 -0400 Received: from fanzine2.igalia.com ([213.97.179.56]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1x4ysJ-0001jK-A3; Fri, 11 Sep 2026 06:52:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Type:MIME-Version:Message-ID:Date:Subject:Cc:To:From: From:Reply-To; bh=vUacKBIksIh7vKNrhaLkEvFsF3e5tm/UIhGN4fzVIbk=; b=AGQatNP8EE3 UHKElVvBRa+EylM1zJtb3HDk9/LqCnrDLrpigc/GtZa4cmaYAuZ8OY0Txa4BfFQrhH4S0fUyxgHpp ceuESYZCqN8SlMAkvIKgmBn5VOeLZM28iUjrBJeaN1WyXaBChtctt20ZmWtvM6jcrMxMWOeV6Q9+r xj3hgDOQxXws3YrYkYw4pkKuv/bAZwH3mUl0F5T0Hqwj0nEbqaxunanIENXSFrlmnRRgI81BsUELm sjt2m0l4ewxj3paFJPrI+JP17y+Dp7uBcCP2xfUTtjnEaD+YHqcOw9xBuy8LeedtuhxeGsPdePFt7 EgS1dFGgRpD4632ZVWwcZ6w==; Received: from maestria.local.igalia.com ([192.168.10.14] helo=mail.igalia.com) by fanzine2.igalia.com with esmtps (Cipher TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim) id 1x4ysA-000dPd-AN; Fri, 11 Sep 2026 12:52:46 +0200 Received: from gate.service.igalia.com ([192.168.21.52]) by mail.igalia.com with esmtp (Exim) id 1x4ys9-001yys-8I; Fri, 11 Sep 2026 12:52:45 +0200 Received: from berto by gate.service.igalia.com with local (Exim 4.96) (envelope-from ) id 1x4ys9-000zCt-0H; Fri, 11 Sep 2026 10:52:45 +0000 From: Alberto Garcia To: "Denis V. Lunev" , qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, qemu-stable@nongnu.org, "Denis V. Lunev" , Kevin Wolf , Hanna Reitz Subject: Re: [PATCH] block/throttle-groups: fix crash when enabling I/O limits on a busy disk In-Reply-To: <20260908145554.3215221-2-den@openvz.org> References: <20260908145554.3215221-1-den@openvz.org> <20260908145554.3215221-2-den@openvz.org> Date: Fri, 11 Sep 2026 12:52:45 +0200 Message-ID: MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=213.97.179.56; envelope-from=berto@igalia.com; helo=fanzine2.igalia.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Tue 08 Sep 2026 04:55:53 PM +02, Denis V. Lunev wrote: > throttle_group_register_tgm() stores tgm->throttle_state before it takes > tg->lock, so the I/O path can see a member whose group still has NULL > tokens[] and an empty member list. A request in an iothread then reaches > throttle_group_co_io_limits_intercept(), wins tg->lock ahead of the > registering thread, and next_throttle_token() passes the NULL token to > throttle_group_next_tgm(), which dereferences it: Acked-by: Alberto Garcia Berto