linux-kernel - Re: [PATCH] mm: fix incorrect behavior when process virtual address space limit is exceeded

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: <564B6605.8080808@ezchip.com>
Date:	Tue, 17 Nov 2015 12:38:13 -0500
From:	Chris Metcalf <cmetcalf@...hip.com>
To:	Oleg Nesterov <oleg@...hat.com>,
	Piotr Kwapulinski <kwapulinski.piotr@...il.com>
CC:	<akpm@...ux-foundation.org>, <mszeredi@...e.cz>,
	<viro@...iv.linux.org.uk>, <dave@...olabs.net>,
	<kirill.shutemov@...ux.intel.com>, <n-horiguchi@...jp.nec.com>,
	<aarcange@...hat.com>, <mhocko@...e.com>, <iamjoonsoo.kim@....com>,
	<jack@...e.cz>, <xiexiuqi@...wei.com>, <vbabka@...e.cz>,
	<Vineet.Gupta1@...opsys.com>, <riel@...hat.com>,
	<gang.chen.5i5j@...il.com>, <linux-kernel@...r.kernel.org>,
	<linux-mm@...ck.org>
Subject: Re: [PATCH] mm: fix incorrect behavior when process virtual address
 space limit is exceeded

On 11/17/2015 11:19 AM, Oleg Nesterov wrote:
> On 11/16, Piotr Kwapulinski wrote:
>> @@ -1551,7 +1552,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
>>   		 * MAP_FIXED may remove pages of mappings that intersects with
>>   		 * requested mapping. Account for the pages it would unmap.
>>   		 */
>> -		if (!(vm_flags & MAP_FIXED))
>> +		if (!(flags & MAP_FIXED))
>>   			return -ENOMEM;
> And afaics arch/tile/mm/elf.c can use do_mmap(MAP_FIXED ...) rather than
> mmap_region(), it can be changed by a separate patch. In this case we can
> unexport mmap_region().

The problem is that we are mapping a region of virtual address space that
the chip provides for setting up interrupt handlers (at 0xfc000000) but that
is above the TASK_SIZE cutoff, so do_mmap() would fail the call in
get_unmapped_area().

-- 
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/