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[2003:cb:c704:7c00:aaa9:2ce5:5aa0:f736]) by smtp.gmail.com with ESMTPSA id e9-20020adfe389000000b0020c5253d8fcsm9690559wrm.72.2022.05.29.23.56.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 29 May 2022 23:56:00 -0700 (PDT) Message-ID: <0563a019-09e3-a176-d4c1-c240f3cf62d0@redhat.com> Date: Mon, 30 May 2022 08:55:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.0 Subject: Re: [PATCH] mm: memory_hotplug: fix memory error handling Content-Language: en-US To: Muchun Song , gregkh@linuxfoundation.org, rafael@kernel.org, cheloha@linux.vnet.ibm.com, mhocko@suse.com, akpm@linux-foundation.org, nathanl@linux.ibm.com Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20220530053326.41682-1-songmuchun@bytedance.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20220530053326.41682-1-songmuchun@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 30.05.22 07:33, Muchun Song wrote: > The device_unregister() is supposed to be used to unregister devices if > device_register() has succeed. And device_unregister() will put device. > The caller should not do it again, otherwise, the first call of > put_device() will drop the last reference count, then the next call > of device_unregister() will UAF on device. > > Fixes: 4fb6eabf1037 ("drivers/base/memory.c: cache memory blocks in xarray to accelerate lookup") > Signed-off-by: Muchun Song > Cc: > --- > drivers/base/memory.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/base/memory.c b/drivers/base/memory.c > index 7222ff9b5e05..084d67fd55cc 100644 > --- a/drivers/base/memory.c > +++ b/drivers/base/memory.c > @@ -636,10 +636,9 @@ static int __add_memory_block(struct memory_block *memory) > } > ret = xa_err(xa_store(&memory_blocks, memory->dev.id, memory, > GFP_KERNEL)); > - if (ret) { > - put_device(&memory->dev); > + if (ret) > device_unregister(&memory->dev); > - } > + > return ret; > } > See https://lkml.kernel.org/r/d44c63d78affe844f020dc02ad6af29abc448fc4.1650611702.git.christophe.jaillet@wanadoo.fr -- Thanks, David / dhildenb