Le 09/03/2022 à 11:46, Michael Ellerman a écrit :
> 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().
I agree with that, but it's a huge work I guess. Most platforms set
.get_irq in ppc_md() at buildtime. See the generic mpic_get_irq() which
has a BUG_ON() in call mpic_primary is NULL. There are 50 platforms with
buildtime assignment.
That would however be a good opportunity to switch get_irq() to a static
call. I'll open a github issue to follow it.
Christophe
