Re: [PATCH] slab: fix an infinite loop in leaks_show()

[Qian Cai]

On 4/11/19 4:20 AM, Vlastimil Babka wrote:
> On 4/11/19 5:26 AM, Qian Cai wrote:
>> "cat /proc/slab_allocators" could hang forever on SMP machines with
>> kmemleak or object debugging enabled due to other CPUs running do_drain()
>> will keep making kmemleak_object or debug_objects_cache dirty and unable
>> to escape the first loop in leaks_show(),
> 
> So what if we don't remove SLAB (yet?) but start removing the debugging
> functionality that has been broken for years and nobody noticed. I think
> Linus already mentioned that we remove at least the
> /proc/slab_allocators file...

In my experience, 2-year isn't that long for debugging features to be silently
broken with SLAB where kmemleak is broken for more than 4-year there. See
92d1d07daad6 ("mm/slab.c: kmemleak no scan alien caches").