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 AE22B144D34; Tue, 23 Apr 2024 21:43:37 +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=1713908617; cv=none; b=fu02S4ZNVs4rOLSdXnN7BS1Uu21JZj7EYF3l/zlu7qAagz3JhvqWvO84DKsSP8HazFiRR0WgCkKBpaWmhG7nHSZs2XUtSEJDNn7+sFri9R2lEjwHhYW93cmqUAOt/vF6k8dkDWTeD2ZsPfi5UcvpKz0mQ8q4OB5ku3wH3OUe+oY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1713908617; c=relaxed/simple; bh=+vaw1aOFdaP5F9H/cin+7MIpPGDPkx8IdMONAuIPqek=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kwSImzzMyFz2IXAZ5vEK/RKreYBqChVaCtzrySoypQDhLofGF1qWXe2Kyt1EXMjDOmEzPzW6Kq5Z79IMRqHHVDmGGghck6XSNAQmWzBwE34X5L5/CbCL5WeelRqrKaNNB77LZrs4UNHRWjeLGkSQ+H7mMDXGTJckAc+/eDsOvjY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=l1sKtoTd; 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="l1sKtoTd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2AB20C116B1; Tue, 23 Apr 2024 21:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1713908617; bh=+vaw1aOFdaP5F9H/cin+7MIpPGDPkx8IdMONAuIPqek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=l1sKtoTdaVxXPMdpyeS7Htb524ITD7S0VWcPPsNbQFSYP08HDuY2h3iAwGrbGdSkk BMaAa4cMxc7VNsH8cugK+KLKy96bhx6adaQrSpqAshjaxPNf+nfW/leOAp2rkll9uI H/crYsHNHI4v+RTdbImpWsoAYaJ2zRISkGV94a7k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mike Tipton , Rob Clark , Georgi Djakov , Sasha Levin Subject: [PATCH 6.6 090/158] interconnect: Dont access req_list while its being manipulated Date: Tue, 23 Apr 2024 14:38:47 -0700 Message-ID: <20240423213858.675063680@linuxfoundation.org> X-Mailer: git-send-email 2.44.0 In-Reply-To: <20240423213855.696477232@linuxfoundation.org> References: <20240423213855.696477232@linuxfoundation.org> User-Agent: quilt/0.67 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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mike Tipton [ Upstream commit de1bf25b6d771abdb52d43546cf57ad775fb68a1 ] The icc_lock mutex was split into separate icc_lock and icc_bw_lock mutexes in [1] to avoid lockdep splats. However, this didn't adequately protect access to icc_node::req_list. The icc_set_bw() function will eventually iterate over req_list while only holding icc_bw_lock, but req_list can be modified while only holding icc_lock. This causes races between icc_set_bw(), of_icc_get(), and icc_put(). Example A: CPU0 CPU1 ---- ---- icc_set_bw(path_a) mutex_lock(&icc_bw_lock); icc_put(path_b) mutex_lock(&icc_lock); aggregate_requests() hlist_for_each_entry(r, ... hlist_del(... Example B: CPU0 CPU1 ---- ---- icc_set_bw(path_a) mutex_lock(&icc_bw_lock); path_b = of_icc_get() of_icc_get_by_index() mutex_lock(&icc_lock); path_find() path_init() aggregate_requests() hlist_for_each_entry(r, ... hlist_add_head(... Fix this by ensuring icc_bw_lock is always held before manipulating icc_node::req_list. The additional places icc_bw_lock is held don't perform any memory allocations, so we should still be safe from the original lockdep splats that motivated the separate locks. [1] commit af42269c3523 ("interconnect: Fix locking for runpm vs reclaim") Signed-off-by: Mike Tipton Fixes: af42269c3523 ("interconnect: Fix locking for runpm vs reclaim") Reviewed-by: Rob Clark Link: https://lore.kernel.org/r/20240305225652.22872-1-quic_mdtipton@quicinc.com Signed-off-by: Georgi Djakov Signed-off-by: Sasha Levin --- drivers/interconnect/core.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c index 50bac2d79d9b5..68edb07d4443e 100644 --- a/drivers/interconnect/core.c +++ b/drivers/interconnect/core.c @@ -176,6 +176,8 @@ static struct icc_path *path_init(struct device *dev, struct icc_node *dst, path->num_nodes = num_nodes; + mutex_lock(&icc_bw_lock); + for (i = num_nodes - 1; i >= 0; i--) { node->provider->users++; hlist_add_head(&path->reqs[i].req_node, &node->req_list); @@ -186,6 +188,8 @@ static struct icc_path *path_init(struct device *dev, struct icc_node *dst, node = node->reverse; } + mutex_unlock(&icc_bw_lock); + return path; } @@ -792,12 +796,16 @@ void icc_put(struct icc_path *path) pr_err("%s: error (%d)\n", __func__, ret); mutex_lock(&icc_lock); + mutex_lock(&icc_bw_lock); + for (i = 0; i < path->num_nodes; i++) { node = path->reqs[i].node; hlist_del(&path->reqs[i].req_node); if (!WARN_ON(!node->provider->users)) node->provider->users--; } + + mutex_unlock(&icc_bw_lock); mutex_unlock(&icc_lock); kfree_const(path->name); -- 2.43.0