* [PATCH 2/4] soc/fsl/qe: fix potential NULL pointer dereference in ucc_of_parse_tdm
@ 2018-11-21 7:41 Wen Yang
2018-11-21 10:45 ` Christophe LEROY
0 siblings, 1 reply; 2+ messages in thread
From: Wen Yang @ 2018-11-21 7:41 UTC (permalink / raw)
To: qiang.zhao
Cc: leoyang.li, linuxppc-dev, linux-arm-kernel, linux-kernel,
zhong.weidong, wang.yi59, wen.yang99, Julia Lawall
This patch fixes a possible null pointer dereference in
ucc_of_parse_tdm, detected by the semantic patch
deref_null.cocci, with the following warning:
./drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced.
The following code has potential null pointer references:
pdev = of_find_device_by_node(np2);
if (!pdev) {
ret = -EINVAL;
pr_err("%pOFn: failed to lookup pdev\n", np2);
of_node_put(np2);
goto err_miss_siram_property;
}
...
err_miss_siram_property:
devm_iounmap(&pdev->dev, utdm->si_regs);
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Reviewed-by: Tan Hu <tan.hu@zte.com.cn>
CC: Julia Lawall <julia.lawall@lip6.fr>
---
drivers/soc/fsl/qe/qe_tdm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
index f78c346..166378b 100644
--- a/drivers/soc/fsl/qe/qe_tdm.c
+++ b/drivers/soc/fsl/qe/qe_tdm.c
@@ -174,7 +174,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
return ret;
err_miss_siram_property:
- devm_iounmap(&pdev->dev, utdm->si_regs);
+ if (pdev)
+ devm_iounmap(&pdev->dev, utdm->si_regs);
return ret;
}
EXPORT_SYMBOL(ucc_of_parse_tdm);
--
2.9.5
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH 2/4] soc/fsl/qe: fix potential NULL pointer dereference in ucc_of_parse_tdm
2018-11-21 7:41 [PATCH 2/4] soc/fsl/qe: fix potential NULL pointer dereference in ucc_of_parse_tdm Wen Yang
@ 2018-11-21 10:45 ` Christophe LEROY
0 siblings, 0 replies; 2+ messages in thread
From: Christophe LEROY @ 2018-11-21 10:45 UTC (permalink / raw)
To: Wen Yang, qiang.zhao
Cc: wang.yi59, zhong.weidong, linux-kernel, leoyang.li, Julia Lawall,
linuxppc-dev, linux-arm-kernel
Le 21/11/2018 à 08:41, Wen Yang a écrit :
> This patch fixes a possible null pointer dereference in
> ucc_of_parse_tdm, detected by the semantic patch
> deref_null.cocci, with the following warning:
>
> ./drivers/soc/fsl/qe/qe_tdm.c:177:21-24: ERROR: pdev is NULL but dereferenced.
>
> The following code has potential null pointer references:
> pdev = of_find_device_by_node(np2);
> if (!pdev) {
> ret = -EINVAL;
> pr_err("%pOFn: failed to lookup pdev\n", np2);
> of_node_put(np2);
> goto err_miss_siram_property;
> }
> ...
> err_miss_siram_property:
> devm_iounmap(&pdev->dev, utdm->si_regs);
>
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Reviewed-by: Tan Hu <tan.hu@zte.com.cn>
> CC: Julia Lawall <julia.lawall@lip6.fr>
> ---
> drivers/soc/fsl/qe/qe_tdm.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/soc/fsl/qe/qe_tdm.c b/drivers/soc/fsl/qe/qe_tdm.c
> index f78c346..166378b 100644
> --- a/drivers/soc/fsl/qe/qe_tdm.c
> +++ b/drivers/soc/fsl/qe/qe_tdm.c
> @@ -174,7 +174,8 @@ int ucc_of_parse_tdm(struct device_node *np, struct ucc_tdm *utdm,
> return ret;
>
> err_miss_siram_property:
> - devm_iounmap(&pdev->dev, utdm->si_regs);
> + if (pdev)
> + devm_iounmap(&pdev->dev, utdm->si_regs);
You are just hiding the issue, not fixing it.
The problem is that pdev gets modified, so in any case that
devm_iounmap() will fail even when the new pdev is valid, because the
iomap was done with a different pdev.
Christophe
> return ret;
> }
> EXPORT_SYMBOL(ucc_of_parse_tdm);
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2018-11-21 10:45 ` Christophe LEROY
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