Thanks for looking into this patch Andrew,
Andrew Donnellan <andrew.donnel...@au1.ibm.com> writes:
> On 08/03/18 21:05, Vaibhav Jain wrote:
>> It is possible for a CXL card to have a valid PSL but no valid
>> AFUs. When this happens we have a valid instance of 'struct cxl'
>> representing the adapter but with its member 'struct cxl_afu *cxl[]'
>> as empty. Unfortunately at many placed within cxl code (especially
>> during an EEH) the elements of this array are passed on to various
>> other cxl functions. Which may result in kernel oops/panic when this
>> 'struct cxl_afu *' is dereferenced.
>>
>> So this patch puts a NULL check at the beginning of various cxl
>> functions that accept 'struct cxl_afu *' as a formal argument and are
>> called from with a loop of the form:
>>
>> for (i = 0; i < adapter->slices; i++) {
>> afu = adapter->afu[i];
>> /* call some function with 'afu' */
>> }
>
> Surely in this case adapter->slices should be 0?
Not necessarily, as adapter->slice doesnt take into account AFUs that
fail to init. I saw this issue in one specific case were the only slice
on the card had issued with the AFU descriptor caused CXL init of that
AFU to fail.
>
> We might still need to harden for other cases...
Yes we may need some more hardening especially in our AFU descriptor
parsing code.
--
Vaibhav Jain <vaib...@linux.vnet.ibm.com>
Linux Technology Center, IBM India Pvt. Ltd.
