linux-kernel - Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <7111317.k6f7A38a4k@wuerfel>
Date:	Fri, 19 Feb 2016 15:41:26 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Murali Karicheri <m-karicheri2@...com>
Cc:	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	davem@...emloft.net
Subject: Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality

On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> 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.
> 
> 			!LAPE	LPAE
> sizeof(void*)		32bit	32bit
> sizeof(dma_addr_t) 	32bit	32bit
> sizeof(phys_addr_t) 	32bit	64bit

As this was never relevant or true, I don't think it needs to be
mentioned here, it just confuses things. Please just assume that
dma_addr_t can be 64-bit wide, but will only contain 32-bit
numbers on keystone.

> 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].

Have you been able to figure out why it actually broke? I'd still
like to know.

> 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 <w-kwok2@...com>
> Cc: Mugunthan V N <mugunthanvnm@...com>
> CC: David Laight <David.Laight@...LAB.COM>
> Reported-by: Franklin S Cooper Jr <fcooper@...com>
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
> Signed-off-by: Murali Karicheri <m-karicheri2@...com>

I don't think I sent this patch with a 'Signed-off-by', did I?
(I could be misremembering that).

	Arnd