netdev - Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP

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Message-ID: <YzG3+vCO23P/1YYp@dhcp22.suse.cz>
Date:   Mon, 26 Sep 2022 16:32:26 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     Florian Westphal <fw@...len.de>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org, vbabka@...e.cz,
        akpm@...ux-foundation.org, urezki@...il.com,
        netdev@...r.kernel.org, netfilter-devel@...r.kernel.org,
        Martin Zaharinov <micron10@...il.com>
Subject: Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC

On Mon 26-09-22 16:20:13, Florian Westphal wrote:
> Michal Hocko <mhocko@...e.com> wrote:
> > On Mon 26-09-22 15:08:08, Florian Westphal wrote:
> > [...]
> > > To the best of my knowledge there are users of this interface that
> > > invoke it with rcu read lock held, and since those always nest, the
> > > rcu_read_unlock() won't move us to GFP_KERNEL territory.
> > 
> > Fiar point. I can see a comment above rhashtable_insert_fast which is
> > supposed to be used by drivers and explicitly documented to be
> > compatible with an atomic context. So the above is clearly a no-go
> > 
> > In that case I would propose to go with the patch going
> > http://lkml.kernel.org/r/YzFplwSxwwsLpzzX@dhcp22.suse.cz direction.
> 
> FWIW that patch works for me. Will you do a formal patch submission?

Feel free to use it and glue it to the actual bug report.

Thanks!

-- 
Michal Hocko
SUSE Labs