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Date: Sat, 5 Sep 2026 16:49:46 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: David Stevens <stevensd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>,
 Roman Gushchin <roman.gushchin@linux.dev>, Shakeel Butt
 <shakeel.butt@linux.dev>, Muchun Song <muchun.song@linux.dev>, Lorenzo
 Stoakes <ljs@kernel.org>, cgroups@vger.kernel.org, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH v2] memcg: Don't call schedule_work when no spinning is
 allowed
Message-Id: <20260905164946.ff22c7cf24445057dadc89a6@linux-foundation.org>
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On Fri,  4 Sep 2026 10:31:45 -0700 David Stevens <stevensd@google.com> wrote:

> Memcg charging can be done from any context, but calling schedule_work()
> isn't safe from an NMI. If memory.high is breached from a context where
> spinning isn't allowed, use irq_work to schedule the reclaim work.
> 
> Fixes: 3ac4638a734a ("memcg: make memcg_rstat_updated nmi safe")

Thanks.

To fill in the desirable statement of user impact, I pasted this from
the v1 thread:

: Found this via code inspection.  I spent a little bit trying to trigger it
: for real, but the only way I managed was by writing a hacky driver absuing
: alloc_pages_nolock().