cpufreq: davinci: Fix clk use after free

Uwe Kleine-König · rafaeljw · commit 5d8f384a9b4f · 2023-02-09T20:26:42.000+01:00
The remove function first frees the clks and only then calls cpufreq_unregister_driver(). If one of the cpufreq callbacks is called just before cpufreq_unregister_driver() is run, the freed clks might be used. Fixes: 6601b80 ("davinci: add generic CPUFreq driver for DaVinci") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/davinci-cpufreq.c b/drivers/cpufreq/davinci-cpufreq.c
@@ -133,13 +133,13 @@ static int __init davinci_cpufreq_probe(struct platform_device *pdev)
 
 static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
 {
+	cpufreq_unregister_driver(&davinci_driver);
+
 	clk_put(cpufreq.armclk);
 
 	if (cpufreq.asyncclk)
 		clk_put(cpufreq.asyncclk);
 
-	cpufreq_unregister_driver(&davinci_driver);
-
 	return 0;
 }
 

Original file line number	Diff line number	Diff line change
`@@ -133,13 +133,13 @@ static int __init davinci_cpufreq_probe(struct platform_device *pdev)`
`133`	`133`
`134`	`134`	`static int __exit davinci_cpufreq_remove(struct platform_device *pdev)`
`135`	`135`	`{`
	`136`	`+ cpufreq_unregister_driver(&davinci_driver);`
	`137`	`+`
`136`	`138`	`clk_put(cpufreq.armclk);`
`137`	`139`
`138`	`140`	`if (cpufreq.asyncclk)`
`139`	`141`	`clk_put(cpufreq.asyncclk);`
`140`	`142`
`141`		`- cpufreq_unregister_driver(&davinci_driver);`
`142`		`-`
`143`	`143`	`return 0;`
`144`	`144`	`}`
`145`	`145`