From:   Johan Hovold <johan+linaro@kernel.org>
To:     Georgi Djakov <djakov@kernel.org>
Cc:     Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Fabio Estevam <festevam@gmail.com>,
        NXP Linux Team <linux-imx@nxp.com>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Sylwester Nawrocki <s.nawrocki@samsung.com>,
        =?UTF-8?q?Artur=20=C5=9Awigo=C5=84?= <a.swigon@samsung.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-arm-msm@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
        linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org,
        Johan Hovold <johan+linaro@kernel.org>, stable@vger.kernel.org
Subject: [PATCH 02/23] interconnect: fix icc_provider_del() error handling
Date:   Wed,  1 Feb 2023 11:15:38 +0100
Message-Id: <20230201101559.15529-3-johan+linaro@kernel.org>
In-Reply-To: <20230201101559.15529-1-johan+linaro@kernel.org>
References: <20230201101559.15529-1-johan+linaro@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The interconnect framework currently expects that providers are only
removed when there are no users and after all nodes have been removed.

There is currently nothing that guarantees this to be the case and the
framework does not do any reference counting, but refusing to remove the
provider is never correct as that would leave a dangling pointer to a
resource that is about to be released in the global provider list (e.g.
accessible through debugfs).

Replace the current sanity checks with WARN_ON() so that the provider is
always removed.

Fixes: 11f1ceca7031 ("interconnect: Add generic on-chip interconnect API")
Cc: stable@vger.kernel.org      # 5.1: 680f8666baf6: interconnect: Make icc_provider_del() return void
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/interconnect/core.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c
index dc61620a0191..43c5c8503ee8 100644
--- a/drivers/interconnect/core.c
+++ b/drivers/interconnect/core.c
@@ -1062,18 +1062,8 @@ EXPORT_SYMBOL_GPL(icc_provider_add);
 void icc_provider_del(struct icc_provider *provider)
 {
 	mutex_lock(&icc_lock);
-	if (provider->users) {
-		pr_warn("interconnect provider still has %d users\n",
-			provider->users);
-		mutex_unlock(&icc_lock);
-		return;
-	}
-
-	if (!list_empty(&provider->nodes)) {
-		pr_warn("interconnect provider still has nodes\n");
-		mutex_unlock(&icc_lock);
-		return;
-	}
+	WARN_ON(provider->users);
+	WARN_ON(!list_empty(&provider->nodes));
 
 	list_del(&provider->provider_list);
 	mutex_unlock(&icc_lock);
-- 
2.39.1