From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnd Bergmann Subject: Re: [PATCH v2 1/3] net: ti: netcp: restore get/set_pad_info() functionality Date: Fri, 19 Feb 2016 21:56:14 +0100 Message-ID: <8660259.RH6vgAvune@wuerfel> References: <1455904724-17952-1-git-send-email-m-karicheri2@ti.com> <1455904724-17952-2-git-send-email-m-karicheri2@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, davem@davemloft.net To: Murali Karicheri Return-path: In-Reply-To: <1455904724-17952-2-git-send-email-m-karicheri2@ti.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Friday 19 February 2016 12:58:42 Murali Karicheri wrote: > The commit 899077791403 ("netcp: try to reduce type confusion in > descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks > get/set_pad_info() functionality. > > The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to > store DMA/MEM buffer pointer and buffer size respectively. And in both > cases for Keystone 2 the pointer type size is 32 bit regardless of > LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally > is not expected to be defined. > > Unfortunately, above commit changed buffer's pointers save/restore > code (get/set_pad_info()) and added intermediate conversation to u64 > which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver > crash in RX/TX path due to "Unable to handle kernel NULL pointer" > exception. This issue was reported and discussed in [1]. > > Hence, fix it by partially reverting above commit and restoring > get/set_pad_info() functionality as it was before. > > [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html > Cc: Wingman Kwok > Cc: Mugunthan V N > CC: David Laight > CC: Arnd Bergmann > Reported-by: Franklin S Cooper Jr > Signed-off-by: Grygorii Strashko > Signed-off-by: Murali Karicheri > Acked-by: Arnd Bergmann