From: Andreas Schwab <schwab@suse.de>
To: Johannes Weiner <hannes@saeurebad.de>
Cc: Roel Kluin <12o3l@tiscali.nl>,
linux-mm@kvack.org, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] pagewalk: don't pte_unmap(NULL) in walk_pte_range()
Date: Thu, 10 Apr 2008 14:09:00 +0200 [thread overview]
Message-ID: <jer6dd9ajn.fsf@sykes.suse.de> (raw)
In-Reply-To: <87zls3qhop.fsf@saeurebad.de> (Johannes Weiner's message of "Wed\, 09 Apr 2008 15\:30\:30 +0200")
Johannes Weiner <hannes@saeurebad.de> writes:
>> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
>> ---
>> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
>> index 1cf1417..6615f0b 100644
>> --- a/mm/pagewalk.c
>> +++ b/mm/pagewalk.c
>> @@ -15,7 +15,7 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>> break;
>> } while (pte++, addr += PAGE_SIZE, addr != end);
>>
>> - pte_unmap(pte);
>> + pte_unmap(pte - 1);
>> return err;
>> }
>
> This does not make any sense to me.
There is something fishy here. If the loop ends because addr == end
then pte has been incremented past the pmd page for addr, no?
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstraße 5, 90409 Nürnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
WARNING: multiple messages have this Message-ID (diff)
From: Andreas Schwab <schwab@suse.de>
To: Johannes Weiner <hannes@saeurebad.de>
Cc: Roel Kluin <12o3l@tiscali.nl>,
linux-mm@kvack.org, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] pagewalk: don't pte_unmap(NULL) in walk_pte_range()
Date: Thu, 10 Apr 2008 14:09:00 +0200 [thread overview]
Message-ID: <jer6dd9ajn.fsf@sykes.suse.de> (raw)
In-Reply-To: <87zls3qhop.fsf@saeurebad.de> (Johannes Weiner's message of "Wed\, 09 Apr 2008 15\:30\:30 +0200")
Johannes Weiner <hannes@saeurebad.de> writes:
>> Signed-off-by: Roel Kluin <12o3l@tiscali.nl>
>> ---
>> diff --git a/mm/pagewalk.c b/mm/pagewalk.c
>> index 1cf1417..6615f0b 100644
>> --- a/mm/pagewalk.c
>> +++ b/mm/pagewalk.c
>> @@ -15,7 +15,7 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
>> break;
>> } while (pte++, addr += PAGE_SIZE, addr != end);
>>
>> - pte_unmap(pte);
>> + pte_unmap(pte - 1);
>> return err;
>> }
>
> This does not make any sense to me.
There is something fishy here. If the loop ends because addr == end
then pte has been incremented past the pmd page for addr, no?
Andreas.
--
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux Products GmbH, Maxfeldstrasse 5, 90409 Nurnberg, Germany
PGP key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."
--
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next prev parent reply other threads:[~2008-04-10 12:09 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-09 10:08 [PATCH] pagewalk: don't pte_unmap(NULL) in walk_pte_range() Roel Kluin
2008-04-09 10:08 ` Roel Kluin
2008-04-09 13:30 ` Johannes Weiner
2008-04-09 13:30 ` Johannes Weiner
2008-04-10 11:42 ` Roel Kluin
2008-04-10 11:42 ` Roel Kluin
2008-04-10 12:09 ` Andreas Schwab [this message]
2008-04-10 12:09 ` Andreas Schwab
2008-04-10 14:01 ` [PATCH] Stay below upper pmd boundary on pte range walk Johannes Weiner
2008-04-10 14:01 ` Johannes Weiner
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