From: David Howells <dhowells@redhat.com>
To: "Aubrey Li" <aubreylee@gmail.com>
Cc: vapier.adi@gmail.com, jie.zhang@analog.com, bryan.wu@analog.com,
"Andrew Morton" <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag
Date: Fri, 30 Mar 2007 12:24:22 +0100 [thread overview]
Message-ID: <15938.1175253862@redhat.com> (raw)
In-Reply-To: <6d6a94c50703300334w6b4787f3p144715de5166d7bc@mail.gmail.com>
Aubrey Li <aubreylee@gmail.com> wrote:
> malloc() allocates size bytes and returns a pointer to the allocated memory.
> ****The memory is not cleared.****
But this is *not* malloc(). It's mmap(). Are you prepared to guarantee that
there are no applications out there that don't rely on anon mmap() giving
zeroed memory?
The MMU-mode clearing is done for security reasons - there shouldn't be any
leakage between processes, and because the zero page can just be faulted in.
Personally, I'd prefer to maintain compatibility with MMU-mode wherever
possible, but I'm happy with overrides like the MAP_UNINITIALISED flag
suggested.
David
next prev parent reply other threads:[~2007-03-30 11:24 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-30 3:42 [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag Wu, Bryan
2007-03-30 3:53 ` Mike Frysinger
2007-03-30 9:39 ` David Howells
2007-03-30 10:34 ` Aubrey Li
2007-03-30 11:24 ` David Howells [this message]
2007-03-30 13:44 ` Aubrey Li
2007-03-30 14:56 ` Alan Cox
2007-03-30 14:38 ` Aubrey Li
2007-03-30 15:11 ` David Howells
2007-03-30 15:46 ` Aubrey Li
2009-10-13 7:44 ` [PATCH] NOMMU: fix malloc performance by adding uninitialized flag Mike Frysinger
2009-10-13 10:10 ` David Howells
2009-10-13 11:20 ` [PATCH v2] " Mike Frysinger
2009-10-13 13:03 ` Paul Mundt
2009-10-13 16:03 ` David Howells
2009-10-13 21:31 ` [PATCH v3] " Mike Frysinger
2009-10-13 23:04 ` David McCullough
2009-10-14 0:25 ` Greg Ungerer
2009-10-13 15:20 ` [uClinux-dev] [PATCH] NOMMU: fix malloc performance by addinguninitialized flag Robin Getz
2007-03-30 18:13 ` [PATCH] nommu arch dont zero the anonymous mapping by adding UNINITIALIZE flag Alan Cox
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