On 9/30/20 3:06 PM, Eric Farman wrote:
>
>
> On 9/30/20 7:37 AM, Vlastimil Babka wrote:
>> On 9/30/20 1:26 PM, Eric Farman wrote:
>>> The routine that applies debug flags to the kmem_cache slabs
>>> inadvertantly prevents non-debug flags from being applied to
>>> those same objects. That is, if slub_debug=<flag>,<slab> is
>>> specified, non-debugged slabs will end up having flags of zero,
>>> and the slabs will be unusable. Fix this by returning the input
>>> flags for non-matching slabs as was done previously.
>>
>> Thanks a lot for debugging this and sorry for the trouble!
>
> You're welcome. Just glad I wasn't losing my mind!
>
>>
>>> Fixes: e17f1dfba37b ("mm, slub: extend slub_debug syntax for multiple blocks")
>>> Signed-off-by: Eric Farman <farman@xxxxxxxxxxxxx>
>>
>> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
>>
>> But with a small adjustment below:
>>
>>> ---
>>> mm/slub.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/mm/slub.c b/mm/slub.c
>>> index d4177aecedf6..3d7c95fd6a08 100644
>>> --- a/mm/slub.c
>>> +++ b/mm/slub.c
>>> @@ -1450,7 +1450,7 @@ slab_flags_t kmem_cache_flags(unsigned int object_size,
>>> }
>>> }
>>>
>>> - return slub_debug;
>>> + return flags;
>>
>> To keep supporting the case of "debug flags set for all caches, with exceptions
>> for listed caches", i.e. "slub_debug=FZ;-,zs_handle,zspage", we should return
>> here this:
>>
>> return flags | slub_debug;
>
> Ah, cool... I wondered about that, but didn't go far enough down the
> combinations. Does it then make sense to strip out the "if
> (!slub_debug_string)" check at the beginning of the function? As in:
Yeah, that makes sense.
Thanks!
