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 3DC191A5A7 for ; Mon, 16 Oct 2023 09:04:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RjcDv5u+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AD9E3C433C9; Mon, 16 Oct 2023 09:04:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1697447057; bh=J35BMIZV7Mw39lQfUSHXQ7qxPGE0T9hx7CGGKjOffE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RjcDv5u+Ajs4pXpdmwdABIP6zZBTbN/HsNwU0yfzmnyaXJ62c2Q3qVgu+mQFQ1+Zx Z1AT1QsBGmN7CKlTSHFySUiBS7CgdOGWXzyhQ/8BbjCvwU3C3QkTV5E3OqrBSX6VmP hrKJTNx8COGlwrfc1E7yC6aeRFcambAiOhOmPm5w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dmitry Torokhov , Linus Walleij Subject: [PATCH 6.1 117/131] pinctrl: avoid unsafe code pattern in find_pinctrl() Date: Mon, 16 Oct 2023 10:41:40 +0200 Message-ID: <20231016084002.974374011@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231016084000.050926073@linuxfoundation.org> References: <20231016084000.050926073@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Torokhov commit c153a4edff6ab01370fcac8e46f9c89cca1060c2 upstream. The code in find_pinctrl() takes a mutex and traverses a list of pinctrl structures. Later the caller bumps up reference count on the found structure. Such pattern is not safe as pinctrl that was found may get deleted before the caller gets around to increasing the reference count. Fix this by taking the reference count in find_pinctrl(), while it still holds the mutex. Cc: stable@vger.kernel.org Signed-off-by: Dmitry Torokhov Link: https://lore.kernel.org/r/ZQs1RgTKg6VJqmPs@google.com Signed-off-by: Linus Walleij Signed-off-by: Greg Kroah-Hartman --- drivers/pinctrl/core.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -1007,17 +1007,20 @@ static int add_setting(struct pinctrl *p static struct pinctrl *find_pinctrl(struct device *dev) { - struct pinctrl *p; + struct pinctrl *entry, *p = NULL; mutex_lock(&pinctrl_list_mutex); - list_for_each_entry(p, &pinctrl_list, node) - if (p->dev == dev) { - mutex_unlock(&pinctrl_list_mutex); - return p; + + list_for_each_entry(entry, &pinctrl_list, node) { + if (entry->dev == dev) { + p = entry; + kref_get(&p->users); + break; } + } mutex_unlock(&pinctrl_list_mutex); - return NULL; + return p; } static void pinctrl_free(struct pinctrl *p, bool inlist); @@ -1126,7 +1129,6 @@ struct pinctrl *pinctrl_get(struct devic p = find_pinctrl(dev); if (p) { dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n"); - kref_get(&p->users); return p; }