Re: [PATCH 5.4 000/168] 5.4.25-stable review

Holger Hoffstätte
2020-03-10T14:51:06Z

On 3/10/20 3:35 PM, Greg Kroah-Hartman wrote:
> On Tue, Mar 10, 2020 at 03:02:37PM +0100, Holger Hoffstätte wrote:
>> On 3/10/20 1:37 PM, Greg Kroah-Hartman wrote:
>>> This is the start of the stable review cycle for the 5.4.25 release.
>>
>> This fails to compile due to broken patch 001/168:
>> "block, bfq: get a ref to a group when adding it to a service tree":
>>
>> ..
>> block/bfq-wf2q.c: In function 'bfq_get_entity':
>> ./include/linux/kernel.h:994:51: error: 'struct bfq_group' has no member named 'entity'
>> ..
>>
>> The calls to bfq_get_entity::bfqg_and_blkg_get and bfq_forget_entity::bfqg_and_blkg_put
>> in bfq-wf2q.c need to be wrapped in #ifdef CONFIG_BFQ_GROUP_IOSCHED, otherwise
>> the build will fail when CONFIG_BFQ_GROUP_IOSCHED is not enabled.
>> This horribly error-prone #ifdef mess was finally removed in upstream commit
>> 4d8340d0d4d9. For 5.4 we'll either need that as well or add them back.
>
> Ick, that's a mess.
>
> I'll go drop that patch now, odd that it passed my build tests...

Uh, please no? It fixes a rather nasty UAF when cgroups are in use.
Please just add the other upstream commit as well, I confirmed it applies
cleanly and fixes the problem.

thanks,
Holger