From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 41FA622D799; Mon, 10 Mar 2025 17:27:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741627642; cv=none; b=qBozOVprJQC4xm3xHS5thG/6sOF9NG+M48GPW7nJAv9+fhlI3IHYhEGTQwcxvZ/5eqdPm9glYejuAp2ghoy31+p+q/9n6wVevFtLaTajfkrS7XPT+DO3TQYXom9OM02PNFCTeBr4Q3i95KgDhxyhe2cZq4ek6xi2WW740kCfO7k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741627642; c=relaxed/simple; bh=i1dWifN11q5b6u/jYRS51kCOT3TbxBJJ9VimInFXbvw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MnKHjafs+bFQvH7mal7Q+zyYKZyfLXYXpym+3PVNi0XQErKglXUglJs1zhxYD6sgQwjQAfm7ruZk6EYDhK45cxYpsf75pbqjddloX0fEoiekhtzQcUnLJjwrL2XSgVpibl5I15pU4G0mbqC/yiVJ736RaK1hU3KQqW0sUzEbdaY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AY9pEbsU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="AY9pEbsU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C1973C4CEEC; Mon, 10 Mar 2025 17:27:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741627642; bh=i1dWifN11q5b6u/jYRS51kCOT3TbxBJJ9VimInFXbvw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AY9pEbsUwcl/bekb2KH68qcHf5sxt9H2yFVVKOVCGVFfBi90xiOO1Xv8mtKb9Ll+X 2zfglQ2wVZllZpeKtXksvkA6JXQAqaWbU+GefJhJVrpUl7Rqn1tjJaMeNZLwl8/xmo fv+gKj00d/DzW7Ux0FEfCLRiBhf2sCu0BTYEO3eM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Zecheng Li , "Peter Zijlstra (Intel)" , Vincent Guittot , Sasha Levin , K Prateek Nayak Subject: [PATCH 6.12 199/269] sched/fair: Fix potential memory corruption in child_cfs_rq_on_list Date: Mon, 10 Mar 2025 18:05:52 +0100 Message-ID: <20250310170505.629635852@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170457.700086763@linuxfoundation.org> References: <20250310170457.700086763@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Zecheng Li [ Upstream commit 3b4035ddbfc8e4521f85569998a7569668cccf51 ] child_cfs_rq_on_list attempts to convert a 'prev' pointer to a cfs_rq. This 'prev' pointer can originate from struct rq's leaf_cfs_rq_list, making the conversion invalid and potentially leading to memory corruption. Depending on the relative positions of leaf_cfs_rq_list and the task group (tg) pointer within the struct, this can cause a memory fault or access garbage data. The issue arises in list_add_leaf_cfs_rq, where both cfs_rq->leaf_cfs_rq_list and rq->leaf_cfs_rq_list are added to the same leaf list. Also, rq->tmp_alone_branch can be set to rq->leaf_cfs_rq_list. This adds a check `if (prev == &rq->leaf_cfs_rq_list)` after the main conditional in child_cfs_rq_on_list. This ensures that the container_of operation will convert a correct cfs_rq struct. This check is sufficient because only cfs_rqs on the same CPU are added to the list, so verifying the 'prev' pointer against the current rq's list head is enough. Fixes a potential memory corruption issue that due to current struct layout might not be manifesting as a crash but could lead to unpredictable behavior when the layout changes. Fixes: fdaba61ef8a2 ("sched/fair: Ensure that the CFS parent is added after unthrottling") Signed-off-by: Zecheng Li Reviewed-and-tested-by: K Prateek Nayak Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Link: https://lore.kernel.org/r/20250304214031.2882646-1-zecheng@google.com Signed-off-by: Sasha Levin --- kernel/sched/fair.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ddc096d6b0c20..58ba14ed8fbcb 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4155,15 +4155,17 @@ static inline bool child_cfs_rq_on_list(struct cfs_rq *cfs_rq) { struct cfs_rq *prev_cfs_rq; struct list_head *prev; + struct rq *rq = rq_of(cfs_rq); if (cfs_rq->on_list) { prev = cfs_rq->leaf_cfs_rq_list.prev; } else { - struct rq *rq = rq_of(cfs_rq); - prev = rq->tmp_alone_branch; } + if (prev == &rq->leaf_cfs_rq_list) + return false; + prev_cfs_rq = container_of(prev, struct cfs_rq, leaf_cfs_rq_list); return (prev_cfs_rq->tg->parent == cfs_rq->tg); -- 2.39.5