linux-kernel - [PATCH V2] soc: qcom: geni: Fix NULL pointer dereference

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Message-Id: <1595237762-6776-1-git-send-email-akashast@codeaurora.org>
Date:   Mon, 20 Jul 2020 15:06:02 +0530
From:   Akash Asthana <akashast@...eaurora.org>
To:     bjorn.andersson@...aro.org
Cc:     mka@...omium.org, linux-kernel@...r.kernel.org,
        saipraka@...eaurora.org, msavaliy@...eaurora.org,
        linux-arm-msm@...r.kernel.org,
        Akash Asthana <akashast@...eaurora.org>
Subject: [PATCH V2] soc: qcom: geni: Fix NULL pointer dereference

pdev struct doesn't exists for the devices whose status are disabled
from DT node, in such cases NULL is returned from 'of_find_device_by_node'
Later when we try to get drvdata from pdev struct NULL pointer dereference
is triggered.

Add a NULL check for return values to fix the issue.

We were hitting this issue when one of QUP is disabled.

Fixes: 048eb908a1f2 ("soc: qcom-geni-se: Add interconnect support to fix earlycon crash")
Reported-by: Sai Prakash Ranjan <saipraka@...eaurora.org>
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>
Signed-off-by: Akash Asthana <akashast@...eaurora.org>
---
Changes in V2:
 - Change variable name 'wrapper_pdev' to 'pdev.

 drivers/soc/qcom/qcom-geni-se.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 355d503..996f20c 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -820,6 +820,7 @@ void geni_remove_earlycon_icc_vote(void)
 	struct geni_wrapper *wrapper;
 	struct device_node *parent;
 	struct device_node *child;
+	struct platform_device *pdev;
 
 	if (!earlycon_wrapper)
 		return;
@@ -829,7 +830,12 @@ void geni_remove_earlycon_icc_vote(void)
 	for_each_child_of_node(parent, child) {
 		if (!of_device_is_compatible(child, "qcom,geni-se-qup"))
 			continue;
-		wrapper = platform_get_drvdata(of_find_device_by_node(child));
+
+		pdev = of_find_device_by_node(child);
+		if (!pdev)
+			continue;
+
+		wrapper = platform_get_drvdata(pdev);
 		icc_put(wrapper->to_core.path);
 		wrapper->to_core.path = NULL;
 
-- 
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