Re: [PATCH v3] powerpc/8xx: fix possible object reference leak

Re: [PATCH v3] powerpc/8xx: fix possible object reference leak

[Christophe Leroy]

Le 26/03/2019 à 11:29, Peng Hao a écrit :

Could you fix your clock or clock setup ?

This emails appears to have been sent today at 11:29 (Paris Time ie 
GMT+1) allthough it is only 7am at the time being.

Christophe

> From: Wen Yang <wen.yang99@zte.com.cn>
> 
> The call to of_find_compatible_node returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
> irq_domain_add_linear also calls of_node_get to increase refcount,
> so irq_domain will not be affected when it is released.
> 
> Detected by coccinelle with the following warnings:
> ./arch/powerpc/platforms/8xx/pic.c:158:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 136, but without a corresponding object release within this function.
> 
> Fixes: a8db8cf0d894 ("irq_domain: Replace irq_alloc_host() with
> revmap-specific initializers")
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Reviewed-by: Peng Hao <peng.hao2@zte.com.cn>
> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Vitaly Bordug <vitb@kernel.crashing.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-kernel@vger.kernel.org
> ---
> v3->v2: set ret to zero explicitly.
> v2->v1: add a Fixes tag.
> 
>   arch/powerpc/platforms/8xx/pic.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/8xx/pic.c b/arch/powerpc/platforms/8xx/pic.c
> index 8d5a25d..9993998 100644
> --- a/arch/powerpc/platforms/8xx/pic.c
> +++ b/arch/powerpc/platforms/8xx/pic.c
> @@ -153,9 +153,9 @@ int mpc8xx_pic_init(void)
>   	if (mpc8xx_pic_host == NULL) {
>   		printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");
>   		ret = -ENOMEM;
> -		goto out;
>   	}
> -	return 0;
> +
> +	ret = 0;
>   
>   out:
>   	of_node_put(np);
> 

[PATCH v3] powerpc/8xx: fix possible object reference leak

[Peng Hao]

From: Wen Yang <wen.yang99@zte.com.cn>

The call to of_find_compatible_node returns a node pointer with refcount
incremented thus it must be explicitly decremented after the last
usage.
irq_domain_add_linear also calls of_node_get to increase refcount,
so irq_domain will not be affected when it is released.

Detected by coccinelle with the following warnings:
./arch/powerpc/platforms/8xx/pic.c:158:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 136, but without a corresponding object release within this function.

Fixes: a8db8cf0d894 ("irq_domain: Replace irq_alloc_host() with
revmap-specific initializers")
Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Peng Hao <peng.hao2@zte.com.cn>
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Vitaly Bordug <vitb@kernel.crashing.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-kernel@vger.kernel.org
---
v3->v2: set ret to zero explicitly.
v2->v1: add a Fixes tag.  

 arch/powerpc/platforms/8xx/pic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/platforms/8xx/pic.c b/arch/powerpc/platforms/8xx/pic.c
index 8d5a25d..9993998 100644
--- a/arch/powerpc/platforms/8xx/pic.c
+++ b/arch/powerpc/platforms/8xx/pic.c
@@ -153,9 +153,9 @@ int mpc8xx_pic_init(void)
 	if (mpc8xx_pic_host == NULL) {
 		printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");
 		ret = -ENOMEM;
-		goto out;
 	}
-	return 0;
+
+	ret = 0;
 
 out:
 	of_node_put(np);
-- 
2.9.5

Re: [v3] powerpc/8xx: fix possible object reference leak

[Michael Ellerman]

On Tue, 2019-03-26 at 10:29:51 UTC, Peng Hao wrote:
> From: Wen Yang <wen.yang99@zte.com.cn>
> 
> The call to of_find_compatible_node returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
> irq_domain_add_linear also calls of_node_get to increase refcount,
> so irq_domain will not be affected when it is released.
> 
> Detected by coccinelle with the following warnings:
> ./arch/powerpc/platforms/8xx/pic.c:158:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 136, but without a corresponding object release within this function.
> 
> Fixes: a8db8cf0d894 ("irq_domain: Replace irq_alloc_host() with
> revmap-specific initializers")
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Suggested-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Reviewed-by: Peng Hao <peng.hao2@zte.com.cn>
> Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Vitaly Bordug <vitb@kernel.crashing.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: linuxppc-dev@lists.ozlabs.org
> Cc: linux-kernel@vger.kernel.org

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/cc76404feaed597bb4f5234d34d3f49e

cheers