linux-kernel - Re: [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone

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: <87h9xeh5im.fsf@linux.vnet.ibm.com>
Date:	Tue, 02 Dec 2014 13:01:29 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Mel Gorman <mgorman@...e.de>
Cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>,
	LinuxPPC-dev <linuxppc-dev@...ts.ozlabs.org>,
	Hugh Dickins <hughd@...gle.com>, Dave Jones <davej@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Ingo Molnar <mingo@...hat.com>,
	Kirill Shutemov <kirill.shutemov@...ux.intel.com>,
	Sasha Levin <sasha.levin@...cle.com>,
	Paul Mackerras <paulus@...ba.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa

Benjamin Herrenschmidt <benh@...nel.crashing.org> writes:

> On Fri, 2014-11-21 at 13:57 +0000, Mel Gorman wrote:
>> void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
>>                 pte_t pte)
>>  {
>> -#ifdef CONFIG_DEBUG_VM
>> -       WARN_ON(pte_val(*ptep) & _PAGE_PRESENT);
>> -#endif
>> +       /*
>> +        * When handling numa faults, we already have the pte marked
>> +        * _PAGE_PRESENT, but we can be sure that it is not in hpte.
>> +        * Hence we can use set_pte_at for them.
>> +        */
>> +       VM_WARN_ON((pte_val(*ptep) & (_PAGE_PRESENT | _PAGE_USER)) ==
>> +               (_PAGE_PRESENT | _PAGE_USER));
>> +
>
> His is that going to fare with set_pte_at() called for kernel pages ?
>

Yes, we won't capture those errors now. But is there any other debug
check i could use to capture the wrong usage of set_pte_at ?

-aneesh

--
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/