Christophe Leroy <christophe.le...@csgroup.eu> writes:
> Le 09/03/2022 à 04:24, Michael Ellerman a écrit :
>> Hangyu Hua <hbh...@gmail.com> writes:
>>> mpc8xx_pic_init() should return -ENOMEM instead of 0 when
>>> irq_domain_add_linear() return NULL. This cause mpc8xx_pics_init to continue
>>> executing even if mpc8xx_pic_host is NULL.
>>>
>>> Fixes: cc76404feaed ("powerpc/8xx: Fix possible device node reference leak")
>>> Signed-off-by: Hangyu Hua <hbh...@gmail.com>
>>> ---
>>> arch/powerpc/platforms/8xx/pic.c | 1 +
>>> 1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/powerpc/platforms/8xx/pic.c
>>> b/arch/powerpc/platforms/8xx/pic.c
>>> index f2ba837249d6..04a6abf14c29 100644
>>> --- a/arch/powerpc/platforms/8xx/pic.c
>>> +++ b/arch/powerpc/platforms/8xx/pic.c
>>> @@ -153,6 +153,7 @@ int __init mpc8xx_pic_init(void)
>>
>> Expanding the context:
>>
>> siu_reg = ioremap(res.start, resource_size(&res));
>> if (siu_reg == NULL) {
>> ret = -EINVAL;
>> goto out;
>> }
>>
>> mpc8xx_pic_host = irq_domain_add_linear(np, 64, &mpc8xx_pic_host_ops,
>> NULL);
>>> if (mpc8xx_pic_host == NULL) {
>>> printk(KERN_ERR "MPC8xx PIC: failed to allocate irq host!\n");
>>> ret = -ENOMEM;
>>> + goto out;
>>> }
>>>
>>> ret = 0;
>>>
>> out:
>> of_node_put(np);
>> return ret;
>> }
>>
>> Proper error cleanup should also undo the ioremap() if
>> irq_domain_add_linear() fails.
>
> Uh ...
>
> If siu_reg is NULL, you get a serious problem when __do_irq() calls
> mpc8xx_get_irq()
Arguably it shouldn't be assigned to ppc_md.get_irq unless
mpc8xx_pic_init() succeeds. See eg. xics_init().
> unsigned int mpc8xx_get_irq(void)
> {
> int irq;
>
> /* For MPC8xx, read the SIVEC register and shift the bits down
> * to get the irq number.
> */
> irq = in_be32(&siu_reg->sc_sivec) >> 26;
>
> if (irq == PIC_VEC_SPURRIOUS)
> return 0;
>
> return irq_linear_revmap(mpc8xx_pic_host, irq);
>
> }
>
>
> So I'll leave siu_reg as is even if irq_domain_add_linear() fails.
>
> Whatever, if we do something about that it should be done in another
> patch I think.
Yeah OK, that's becoming a bit of a larger cleanup. I'll take this patch
as-is.
cheers
