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From: David Mosberger <davidm@napali.hpl.hp.com>
To: Mark Haverkamp <markh@osdl.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	davidm@hpl.hp.com, Linus Torvalds <torvalds@osdl.org>,
	Jakub Jelinek <jakub@redhat.com>,
	suresh.b.siddha@intel.com, jun.nakajima@intel.com,
	Andrew Morton <akpm@osdl.org>,
	linux-ia64@vger.kernel.org,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: serious performance regression due to NX patch
Date: Sat, 17 Jul 2004 00:06:10 +0000	[thread overview]
Message-ID: <16632.28018.130890.290832@napali.hpl.hp.com> (raw)
In-Reply-To: <1089734729.1356.79.camel@markh1.pdx.osdl.net>

>>>>> On Tue, 13 Jul 2004 09:05:29 -0700, Mark Haverkamp <markh@osdl.org> said:

  Mark> I think that there is  a problem with this piece of code in
  Mark> binfmt_elf.c:

  Mark> if (i = elf_ex.e_phnum)
  Mark>    def_flags |= VM_EXEC | VM_MAYEXEC;

I think there are other problems, too:

 - any fork() will reset mm->def_flags to zero so if you exec
   an old binary and it does a fork, future mmaps() won't
   have the execute-bit turned on any more; perhaps a rare problem,
   but it certainly seems an illogical behavior

 - likewise for do_mlockall(): it stomps on def_flags without preserving
   the old bits

Am I missing something?

	--david

WARNING: multiple messages have this Message-ID (diff)
From: David Mosberger <davidm@napali.hpl.hp.com>
To: Mark Haverkamp <markh@osdl.org>
Cc: Ingo Molnar <mingo@redhat.com>,
	davidm@hpl.hp.com, Linus Torvalds <torvalds@osdl.org>,
	Jakub Jelinek <jakub@redhat.com>,
	suresh.b.siddha@intel.com, jun.nakajima@intel.com,
	Andrew Morton <akpm@osdl.org>,
	linux-ia64@vger.kernel.org,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: serious performance regression due to NX patch
Date: Fri, 16 Jul 2004 17:06:10 -0700	[thread overview]
Message-ID: <16632.28018.130890.290832@napali.hpl.hp.com> (raw)
In-Reply-To: <1089734729.1356.79.camel@markh1.pdx.osdl.net>

>>>>> On Tue, 13 Jul 2004 09:05:29 -0700, Mark Haverkamp <markh@osdl.org> said:

  Mark> I think that there is  a problem with this piece of code in
  Mark> binfmt_elf.c:

  Mark> if (i == elf_ex.e_phnum)
  Mark>    def_flags |= VM_EXEC | VM_MAYEXEC;

I think there are other problems, too:

 - any fork() will reset mm->def_flags to zero so if you exec
   an old binary and it does a fork, future mmaps() won't
   have the execute-bit turned on any more; perhaps a rare problem,
   but it certainly seems an illogical behavior

 - likewise for do_mlockall(): it stomps on def_flags without preserving
   the old bits

Am I missing something?

	--david

  parent reply	other threads:[~2004-07-17  0:06 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-10  5:28 serious performance regression due to NX patch David Mosberger
2004-07-10  5:28 ` David Mosberger
2004-07-11  8:38 ` Ingo Molnar
2004-07-11  8:38   ` Ingo Molnar
2004-07-11  9:39   ` Ingo Molnar
2004-07-11  9:39     ` Ingo Molnar
2004-07-11  9:52     ` Ingo Molnar
2004-07-11  9:52       ` Ingo Molnar
2004-07-11 10:02       ` Andrew Morton
2004-07-11 10:02         ` Andrew Morton
2004-07-11 12:19         ` Matthew Wilcox
2004-07-11 12:19           ` Matthew Wilcox
2004-07-11 10:22       ` Christoph Hellwig
2004-07-11 10:22         ` Christoph Hellwig
2004-07-11 12:38       ` Jakub Jelinek
2004-07-11 12:38         ` Jakub Jelinek
2004-07-12 18:08         ` Ingo Molnar
2004-07-12 18:08           ` Ingo Molnar
2004-07-12 18:24           ` Christoph Hellwig
2004-07-12 18:24             ` Christoph Hellwig
2004-07-12 18:29             ` Ingo Molnar
2004-07-12 18:29               ` Ingo Molnar
2004-07-12 19:10               ` David Mosberger
2004-07-12 19:10                 ` David Mosberger
2004-07-12 19:54                 ` Ingo Molnar
2004-07-12 19:54                   ` Ingo Molnar
2004-07-12 20:08                   ` David Mosberger
2004-07-12 20:08                     ` David Mosberger
2004-07-12 20:17           ` Linus Torvalds
2004-07-12 20:17             ` Linus Torvalds
2004-07-12 20:21             ` David Mosberger
2004-07-12 20:21               ` David Mosberger
2004-07-12 20:24             ` David Mosberger
2004-07-12 20:24               ` David Mosberger
2004-07-13  4:23               ` Ingo Molnar
2004-07-13  4:23                 ` Ingo Molnar
2004-07-13  5:23                 ` David Mosberger
2004-07-13  5:23                   ` David Mosberger
2004-07-13 16:05                 ` Mark Haverkamp
2004-07-13 16:05                   ` Mark Haverkamp
2004-07-13 16:49                   ` Daniel McNeil
2004-07-13 16:49                     ` Daniel McNeil
2004-07-14 18:36                     ` [PATCH] mmap PROT_NONE fix (was Re: serious performance regression Daniel McNeil
2004-07-14 18:36                       ` [PATCH] mmap PROT_NONE fix (was Re: serious performance regression due to NX patch) Daniel McNeil
2004-07-17  0:06                   ` David Mosberger [this message]
2004-07-17  0:06                     ` serious performance regression due to NX patch David Mosberger
2004-07-17  1:39                     ` Linus Torvalds
2004-07-17  1:39                       ` Linus Torvalds
2004-07-17  4:37                       ` David Mosberger
2004-07-17  4:37                         ` David Mosberger
2004-07-13  3:58             ` Ingo Molnar
2004-07-13  3:58               ` Ingo Molnar
2004-07-17  0:35     ` David Mosberger
2004-07-17  0:35       ` David Mosberger
     [not found] <2giKE-67F-1@gated-at.bofh.it>
     [not found] ` <2gIc8-6pd-29@gated-at.bofh.it>
     [not found]   ` <2gJ8a-72b-11@gated-at.bofh.it>
     [not found]     ` <2gJhY-776-21@gated-at.bofh.it>
2004-07-11 10:09       ` Andi Kleen
2004-07-11 11:56         ` Ingo Molnar
2004-07-11 12:43           ` Andi Kleen
     [not found]       ` <2gJrv-7kp-5@gated-at.bofh.it>
     [not found]         ` <2gLD2-qn-3@gated-at.bofh.it>
2004-07-11 13:38           ` Andi Kleen
2004-07-11 14:04             ` Matthew Wilcox

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