Subject: 答复: Re: [PATCH v2] powerpc/8xx: fix possible object reference leak

From: <[email-masked]>
Date: Tue, 26 Mar 2019 09:19:11 +0800 (CST)

>> 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 <[email-masked]>
>> Suggested-by: Christophe Leroy <[email-masked]>
>> Reviewed-by: Peng Hao <[email-masked]>
>> Cc: Vitaly Bordug <[email-masked]>
>> Cc: Benjamin Herrenschmidt <[email-masked]>
>> Cc: Paul Mackerras <[email-masked]>
>> Cc: Michael Ellerman <[email-masked]>
>> Cc: [email-masked]
>> Cc: [email-masked]
>> ---
>>  arch/powerpc/platforms/8xx/pic.c | 2 --
>>  1 file changed, 2 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/8xx/pic.c b/arch/powerpc/platforms/8xx/pic.c
>> index 8d5a25d..4453df6 100644
>> --- a/arch/powerpc/platforms/8xx/pic.c
>> +++ b/arch/powerpc/platforms/8xx/pic.c
>> @@ -153,9 +153,7 @@ 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;
> 
> It's fragile to rely on ret being equal to zero here. If the code
> further up is changed it's easy enough to miss that ret is expected to
> be zero.
> 
> Better to set it to zero here explicitly, this is the success path after
> all, eg:
> 
> ret = 0;
> 

Thank you for your comments.
I'll fix it soon.

Thanks and regards,
Wen