Messages in this thread | | | Date | Fri, 14 Jun 2019 08:38:37 -0700 | From | Tejun Heo <> | Subject | Re: [BUG] lockdep splat with kernfs lockdep annotations and slab mutex from drm patch?? |
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Hello,
On Fri, Jun 14, 2019 at 04:08:33PM +0100, Chris Wilson wrote: > #ifdef CONFIG_MEMCG > if (slab_state >= FULL && err >= 0 && is_root_cache(s)) { > struct kmem_cache *c; > > mutex_lock(&slab_mutex); > > so it happens to hit the error + FULL case with the additional slabcaches? > > Anyway, according to lockdep, it is dangerous to use the slab_mutex inside > slab_attr_store().
Didn't really look into the code but it looks like slab_mutex is held while trying to remove sysfs files. sysfs file removal flushes on-going accesses, so if a file operation then tries to grab a mutex which is held during removal, it leads to a deadlock.
Thanks.
-- tejun
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