Re: [PATCH 0/2 v8] oom: capture unreclaimable slab info in oom message

[Tetsuo Handa]

On 2017/09/28 6:46, Yang Shi wrote:
> Changelog v7 â> v8:
> * Adopted Michalâs suggestion to dump unreclaim slab info when unreclaimable slabs amount > total user memory. Not only in oom panic path.

Holding slab_mutex inside dump_unreclaimable_slab() was refrained since V2
because there are

	mutex_lock(&slab_mutex);
	kmalloc(GFP_KERNEL);
	mutex_unlock(&slab_mutex);

users. If we call dump_unreclaimable_slab() for non OOM panic path, aren't we
introducing a risk of crash (i.e. kernel panic) for regular OOM path?

We can try mutex_trylock() from dump_unreclaimable_slab() at best.
But it is still remaining unsafe, isn't it?