Hello,

> On 18 Sep 2021, at 17:27, Peter Müller <peter.mueller(a)ipfire.org> wrote:
> 
> Hello Michael,
> hello *,
> 
> at the time of writing, I agree.
> 
> Cross-check hardening features of kernel 5.10.x is an item still open on my todo list, and
> I will hopefully have some spare time for this next month. I will reevaluate SLUB debugging
> then as well, since kernsec mentions this to be necessary for some page poisoning options
> (whyever that is...).

Err. No. Why?

We want the distribution to be stable. And that means that we want to make consistent and long-standing changes.

Changing something back and forth for no reason apart from not having enough time to look into things properly right now is not what I would consider “stable”.

We can either drop this patch (i.e. NACK by you), or we can accept it and leave it.

As far as I can see this debugging option didn’t add any other configuration options that would be otherwise unavailable; and it significantly decreases the size of the memory allocator which should result in performance gains on smaller hardware with smaller CPU caches:

https://cateee.net/lkddb/web-lkddb/SLUB_DEBUG.html

-Michael

> 
> Acked-by: Peter Müller <peter.mueller(a)ipfire.org>
> 
> Thanks, and best regards,
> Peter Müller
> 
> 
>> This is not necessary on our systems and according to the documentation
>> will reduce code size of the allocator which will result in better
>> performance.
>> Signed-off-by: Michael Tremer <michael.tremer(a)ipfire.org>
>> ---
>>  config/kernel/kernel.config.aarch64-ipfire | 3 +--
>>  config/kernel/kernel.config.armv6l-ipfire  | 3 +--
>>  config/kernel/kernel.config.i586-ipfire    | 3 +--
>>  config/kernel/kernel.config.x86_64-ipfire  | 3 +--
>>  4 files changed, 4 insertions(+), 8 deletions(-)
>> diff --git a/config/kernel/kernel.config.aarch64-ipfire b/config/kernel/kernel.config.aarch64-ipfire
>> index d0ec69ba9..b277a17b5 100644
>> --- a/config/kernel/kernel.config.aarch64-ipfire
>> +++ b/config/kernel/kernel.config.aarch64-ipfire
>> @@ -226,7 +226,7 @@ CONFIG_PERF_EVENTS=y
>>  # end of Kernel Performance Events And Counters
>>    CONFIG_VM_EVENT_COUNTERS=y
>> -CONFIG_SLUB_DEBUG=y
>> +# CONFIG_SLUB_DEBUG is not set
>>  # CONFIG_SLUB_MEMCG_SYSFS_ON is not set
>>  # CONFIG_COMPAT_BRK is not set
>>  # CONFIG_SLAB is not set
>> @@ -7751,7 +7751,6 @@ CONFIG_GENERIC_PTDUMP=y
>>  CONFIG_PTDUMP_CORE=y
>>  # CONFIG_PTDUMP_DEBUGFS is not set
>>  # CONFIG_DEBUG_OBJECTS is not set
>> -# CONFIG_SLUB_DEBUG_ON is not set
>>  # CONFIG_SLUB_STATS is not set
>>  CONFIG_HAVE_DEBUG_KMEMLEAK=y
>>  # CONFIG_DEBUG_KMEMLEAK is not set
>> diff --git a/config/kernel/kernel.config.armv6l-ipfire b/config/kernel/kernel.config.armv6l-ipfire
>> index a23906796..9d63b36ac 100644
>> --- a/config/kernel/kernel.config.armv6l-ipfire
>> +++ b/config/kernel/kernel.config.armv6l-ipfire
>> @@ -227,7 +227,7 @@ CONFIG_PERF_EVENTS=y
>>  # end of Kernel Performance Events And Counters
>>    CONFIG_VM_EVENT_COUNTERS=y
>> -CONFIG_SLUB_DEBUG=y
>> +# CONFIG_SLUB_DEBUG is not set
>>  # CONFIG_SLUB_MEMCG_SYSFS_ON is not set
>>  # CONFIG_COMPAT_BRK is not set
>>  # CONFIG_SLAB is not set
>> @@ -7826,7 +7826,6 @@ CONFIG_DEBUG_MISC=y
>>  # CONFIG_DEBUG_RODATA_TEST is not set
>>  # CONFIG_DEBUG_WX is not set
>>  # CONFIG_DEBUG_OBJECTS is not set
>> -# CONFIG_SLUB_DEBUG_ON is not set
>>  # CONFIG_SLUB_STATS is not set
>>  CONFIG_HAVE_DEBUG_KMEMLEAK=y
>>  # CONFIG_DEBUG_KMEMLEAK is not set
>> diff --git a/config/kernel/kernel.config.i586-ipfire b/config/kernel/kernel.config.i586-ipfire
>> index 9c49a90d8..56b40eac7 100644
>> --- a/config/kernel/kernel.config.i586-ipfire
>> +++ b/config/kernel/kernel.config.i586-ipfire
>> @@ -235,7 +235,7 @@ CONFIG_PERF_EVENTS=y
>>  # end of Kernel Performance Events And Counters
>>    CONFIG_VM_EVENT_COUNTERS=y
>> -CONFIG_SLUB_DEBUG=y
>> +# CONFIG_SLUB_DEBUG is not set
>>  # CONFIG_COMPAT_BRK is not set
>>  # CONFIG_SLAB is not set
>>  CONFIG_SLUB=y
>> @@ -7383,7 +7383,6 @@ CONFIG_GENERIC_PTDUMP=y
>>  CONFIG_PTDUMP_CORE=y
>>  # CONFIG_PTDUMP_DEBUGFS is not set
>>  # CONFIG_DEBUG_OBJECTS is not set
>> -# CONFIG_SLUB_DEBUG_ON is not set
>>  # CONFIG_SLUB_STATS is not set
>>  CONFIG_HAVE_DEBUG_KMEMLEAK=y
>>  # CONFIG_DEBUG_KMEMLEAK is not set
>> diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel.config.x86_64-ipfire
>> index 0a1f67074..8247e9b48 100644
>> --- a/config/kernel/kernel.config.x86_64-ipfire
>> +++ b/config/kernel/kernel.config.x86_64-ipfire
>> @@ -245,7 +245,7 @@ CONFIG_PERF_EVENTS=y
>>  # end of Kernel Performance Events And Counters
>>    CONFIG_VM_EVENT_COUNTERS=y
>> -CONFIG_SLUB_DEBUG=y
>> +# CONFIG_SLUB_DEBUG is not set
>>  # CONFIG_COMPAT_BRK is not set
>>  # CONFIG_SLAB is not set
>>  CONFIG_SLUB=y
>> @@ -7249,7 +7249,6 @@ CONFIG_GENERIC_PTDUMP=y
>>  CONFIG_PTDUMP_CORE=y
>>  # CONFIG_PTDUMP_DEBUGFS is not set
>>  # CONFIG_DEBUG_OBJECTS is not set
>> -# CONFIG_SLUB_DEBUG_ON is not set
>>  # CONFIG_SLUB_STATS is not set
>>  CONFIG_HAVE_DEBUG_KMEMLEAK=y
>>  # CONFIG_DEBUG_KMEMLEAK is not set