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[87.59.106.155]) by smtp.gmail.com with ESMTPSA id n21sm497430lfe.153.2022.01.22.00.31.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 22 Jan 2022 00:31:18 -0800 (PST) From: Jesper Dangaard Brouer X-Google-Original-From: Jesper Dangaard Brouer Message-ID: <5bd8f1bd-1a21-df1b-6d6f-9fe5657fdd7c@redhat.com> Date: Sat, 22 Jan 2022 09:31:17 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Cc: brouer@redhat.com, LKML , Network Development , =?UTF-8?Q?Toke_H=c3=b8iland-J=c3=b8rgensen?= , John Fastabend , Alexei Starovoitov , Jakub Kicinski , "David S. Miller" , Ilias Apalodimas , Jesper Dangaard Brouer Subject: Re: [net RFC v1 1/1] page_pool: fix NULL dereference crash Content-Language: en-US To: Colin Foster , Alexei Starovoitov References: <20220122005644.802352-1-colin.foster@in-advantage.com> <20220122005644.802352-2-colin.foster@in-advantage.com> <20220122024051.GA905413@euler> In-Reply-To: <20220122024051.GA905413@euler> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 22/01/2022 03.40, Colin Foster wrote: > On Fri, Jan 21, 2022 at 05:13:28PM -0800, Alexei Starovoitov wrote: >> On Fri, Jan 21, 2022 at 4:57 PM Colin Foster >> wrote: >>> >>> Check for the existence of page pool params before dereferencing. This can >>> cause crashes in certain conditions. >> >> In what conditions? >> Out of tree driver? >> >>> Fixes: 35b2e549894b ("page_pool: Add callback to init pages when they are >>> allocated") >>> >>> Signed-off-by: Colin Foster >>> --- >>> net/core/page_pool.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/net/core/page_pool.c b/net/core/page_pool.c >>> index bd62c01a2ec3..641f849c95e7 100644 >>> --- a/net/core/page_pool.c >>> +++ b/net/core/page_pool.c >>> @@ -213,7 +213,7 @@ static void page_pool_set_pp_info(struct page_pool *pool, >>> { >>> page->pp = pool; >>> page->pp_magic |= PP_SIGNATURE; >>> - if (pool->p.init_callback) >>> + if (pool->p && pool->p.init_callback) > > And my apologies - this should be if (pool... not if (pool->p. kernelbot > will be sure to tell me of this blunder soon Can you confirm if your crash is fixed by this change? >>> pool->p.init_callback(page, pool->p.init_arg); >>> }