linux-kernel - [PATCH 5.8 444/633] pwm: img: Fix null pointer access in probe

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Message-Id: <20201027135543.549006220@linuxfoundation.org>
Date:   Tue, 27 Oct 2020 14:53:07 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hauke Mehrtens <hauke@...ke-m.de>,
        Lee Jones <lee.jones@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.8 444/633] pwm: img: Fix null pointer access in probe

From: Hauke Mehrtens <hauke@...ke-m.de>

[ Upstream commit b39c0615d0667b3a6f2f5c4bf99ffadf3b518bb1 ]

dev_get_drvdata() is called in img_pwm_runtime_resume() before the
driver data is set.
When pm_runtime_enabled() returns false in img_pwm_probe() it calls
img_pwm_runtime_resume() which results in a null pointer access.

This patch fixes the problem by setting the driver data earlier in the
img_pwm_probe() function.

This crash was seen when booting the Imagination Technologies Creator
Ci40 (Marduk) with kernel 5.4 in OpenWrt.

Fixes: e690ae526216 ("pwm: img: Add runtime PM")
Signed-off-by: Hauke Mehrtens <hauke@...ke-m.de>
Acked-by: Lee Jones <lee.jones@...aro.org>
Signed-off-by: Thierry Reding <thierry.reding@...il.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pwm/pwm-img.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-img.c b/drivers/pwm/pwm-img.c
index 599a0f66a3845..a34d95ed70b20 100644
--- a/drivers/pwm/pwm-img.c
+++ b/drivers/pwm/pwm-img.c
@@ -277,6 +277,8 @@ static int img_pwm_probe(struct platform_device *pdev)
 		return PTR_ERR(pwm->pwm_clk);
 	}
 
+	platform_set_drvdata(pdev, pwm);
+
 	pm_runtime_set_autosuspend_delay(&pdev->dev, IMG_PWM_PM_TIMEOUT);
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
@@ -313,7 +315,6 @@ static int img_pwm_probe(struct platform_device *pdev)
 		goto err_suspend;
 	}
 
-	platform_set_drvdata(pdev, pwm);
 	return 0;
 
 err_suspend:
-- 
2.25.1