* [PATCH] cpufreq: mediatek: guard error paths to avoid kernel panic
@ 2023-03-23 11:04 Daniel Golle
2023-03-23 11:43 ` AngeloGioacchino Del Regno
0 siblings, 1 reply; 2+ messages in thread
From: Daniel Golle @ 2023-03-23 11:04 UTC (permalink / raw)
To: linux-pm, linux-mediatek, linux-arm-kernel, linux-kernel,
Rafael J. Wysocki, Viresh Kumar, Matthias Brugger,
AngeloGioacchino Del Regno
Cc: Sam Shih, John Crispin
Guard pointer access in error path of mtk_cpu_dvfs_info_init() to
make sure info->proc_reg and info->sram_reg are valid pointers before
accessing them, which would result in kernel panic e.g. in case of
them being set to -EPROBE_DEFER.
Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators")
Reported-by: Sam Shih <sam.shih@mediatek.com>
Suggested-by: Sam Shih <sam.shih@mediatek.com>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
drivers/cpufreq/mediatek-cpufreq.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 4466d0c91a6a..980a31ddd0f2 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -579,10 +579,12 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
dev_pm_opp_of_cpumask_remove_table(&info->cpus);
out_free_resources:
- if (regulator_is_enabled(info->proc_reg))
- regulator_disable(info->proc_reg);
- if (info->sram_reg && regulator_is_enabled(info->sram_reg))
- regulator_disable(info->sram_reg);
+ if (!IS_ERR(info->proc_reg))
+ if (regulator_is_enabled(info->proc_reg))
+ regulator_disable(info->proc_reg);
+ if (!IS_ERR(info->sram_reg))
+ if (info->sram_reg && regulator_is_enabled(info->sram_reg))
+ regulator_disable(info->sram_reg);
if (!IS_ERR(info->proc_reg))
regulator_put(info->proc_reg);
--
2.40.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cpufreq: mediatek: guard error paths to avoid kernel panic
2023-03-23 11:04 [PATCH] cpufreq: mediatek: guard error paths to avoid kernel panic Daniel Golle
@ 2023-03-23 11:43 ` AngeloGioacchino Del Regno
0 siblings, 0 replies; 2+ messages in thread
From: AngeloGioacchino Del Regno @ 2023-03-23 11:43 UTC (permalink / raw)
To: Daniel Golle, linux-pm, linux-mediatek, linux-arm-kernel,
linux-kernel, Rafael J. Wysocki, Viresh Kumar, Matthias Brugger
Cc: Sam Shih, John Crispin
Il 23/03/23 12:04, Daniel Golle ha scritto:
> Guard pointer access in error path of mtk_cpu_dvfs_info_init() to
> make sure info->proc_reg and info->sram_reg are valid pointers before
> accessing them, which would result in kernel panic e.g. in case of
> them being set to -EPROBE_DEFER.
>
> Fixes: 4b9ceb757bbb ("cpufreq: mediatek: Enable clocks and regulators")
> Reported-by: Sam Shih <sam.shih@mediatek.com>
> Suggested-by: Sam Shih <sam.shih@mediatek.com>
> Signed-off-by: Daniel Golle <daniel@makrotopia.org>
> ---
> drivers/cpufreq/mediatek-cpufreq.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index 4466d0c91a6a..980a31ddd0f2 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -579,10 +579,12 @@ static int mtk_cpu_dvfs_info_init(struct mtk_cpu_dvfs_info *info, int cpu)
> dev_pm_opp_of_cpumask_remove_table(&info->cpus);
>
> out_free_resources:
> - if (regulator_is_enabled(info->proc_reg))
> - regulator_disable(info->proc_reg);
> - if (info->sram_reg && regulator_is_enabled(info->sram_reg))
> - regulator_disable(info->sram_reg);
> + if (!IS_ERR(info->proc_reg))
> + if (regulator_is_enabled(info->proc_reg))
> + regulator_disable(info->proc_reg);
> + if (!IS_ERR(info->sram_reg))
For both, actually, if you suspect that (xxxx)_reg may be NULL, then you should
use IS_ERR_OR_NULL() instead...
> + if (info->sram_reg && regulator_is_enabled(info->sram_reg))
...otherwise, here it's useless to check if it's not NULL?
Regards,
Angelo
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-03-23 11:43 ` AngeloGioacchino Del Regno
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