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From:   John Garry <john.garry@huawei.com>
To:     <xuwei5@huawei.com>
CC:     <bhelgaas@google.com>, <linuxarm@huawei.com>, <arm@kernel.org>,
        <linux-kernel@vger.kernel.org>, <joe@perches.com>,
        John Garry <john.garry@huawei.com>
Subject: [PATCH v2] bus: hisi_lpc: Don't use devm_kzalloc() to allocate logical PIO range
Date:   Fri, 14 Jun 2019 18:24:53 +0800
Message-ID: <1560507893-42553-1-git-send-email-john.garry@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

If, after registering a logical PIO range, the driver probe later fails,
the logical PIO range memory will be released automatically.

This causes an issue, in that the logical PIO range is not unregistered
(that is not supported) and the released range memory may be later
referenced

Allocate the logical PIO range with kzalloc() to avoid this potential
issue.

Fixes: adf38bb0b5956 ("HISI LPC: Support the LPC host on Hip06/Hip07 with DT bindings")
Signed-off-by: John Garry <john.garry@huawei.com>
---

Change to v1:
- add comment, as advised by Joe Perches

diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
index 19d7b6ff2f17..5f0130a693fe 100644
--- a/drivers/bus/hisi_lpc.c
+++ b/drivers/bus/hisi_lpc.c
@@ -599,7 +599,8 @@ static int hisi_lpc_probe(struct platform_device *pdev)
 	if (IS_ERR(lpcdev->membase))
 		return PTR_ERR(lpcdev->membase);
 
-	range = devm_kzalloc(dev, sizeof(*range), GFP_KERNEL);
+	/* Logical PIO may reference 'range' memory even if the probe fails */
+	range = kzalloc(sizeof(*range), GFP_KERNEL);
 	if (!range)
 		return -ENOMEM;
 
@@ -610,6 +611,7 @@ static int hisi_lpc_probe(struct platform_device *pdev)
 	ret = logic_pio_register_range(range);
 	if (ret) {
 		dev_err(dev, "register IO range failed (%d)!\n", ret);
+		kfree(range);
 		return ret;
 	}
 	lpcdev->io_host = range;
-- 
2.17.1