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Date: Sat, 07 Apr 2007 13:54:30 +0200
From: Eric Dumazet <dada1@cosmosbay.com>
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To: Jakub Jelinek <jakub@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>, Dave Jones <davej@redhat.com>,
       Ulrich Drepper <drepper@gmail.com>,
       Nick Piggin <nickpiggin@yahoo.com.au>, Ingo Molnar <mingo@elte.hu>,
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Subject: Re: [PATCH, take4] FUTEX : new PRIVATE futexes
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Jakub Jelinek a écrit :
> On Sat, Apr 07, 2007 at 10:43:39AM +0200, Eric Dumazet wrote:
>> get_futex_key() does a check against sizeof(u32) regardless of futex being 64bits or not.
>> So it is possible a 64bit futex spans two pages of memory...
> 
> That would be a user bug.  32-bit futexes have to be 32-bit aligned, 64-bit
> futexes have to be 64-bit aligned.

I am not sure what you want to say.

User doing sys_futex64(0x......FFC, FUTEX_WAKE_OP, ...) and crashing kernel or 
corrupting data is ok because its a user bug ?


User is allowed to do anything, kernel must check and protect innocents.