Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Mon, 26 Sep 2022 16:32:26 +0200
From:   Michal Hocko <mhocko@suse.com>
To:     Florian Westphal <fw@strlen.de>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz,
        akpm@linux-foundation.org, urezki@gmail.com,
        netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
        Martin Zaharinov <micron10@gmail.com>
Subject: Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC
Message-ID: <YzG3+vCO23P/1YYp@dhcp22.suse.cz>
References: <20220923133512.GE22541@breakpoint.cc>
 <YzFZf0Onm6/UH7/I@dhcp22.suse.cz>
 <20220926075639.GA908@breakpoint.cc>
 <YzFplwSxwwsLpzzX@dhcp22.suse.cz>
 <YzFxHlYoncuDl2fM@dhcp22.suse.cz>
 <20220926100800.GB12777@breakpoint.cc>
 <YzGUyWlYd15uLu7G@dhcp22.suse.cz>
 <20220926130808.GD12777@breakpoint.cc>
 <YzGxuZ8jQ2sO4ZML@dhcp22.suse.cz>
 <20220926142013.GF12777@breakpoint.cc>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20220926142013.GF12777@breakpoint.cc>
Precedence: bulk

On Mon 26-09-22 16:20:13, Florian Westphal wrote:
> Michal Hocko <mhocko@suse.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