This is a note to let you know that we have just queued up the patch titled
Subject: UML - host VDSO fix
to the 2.6.20-stable tree. Its filename is
uml-host-vdso-fix.patch
A git repo of this tree can be found at
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
>From [EMAIL PROTECTED] Fri Mar 23 12:41:21 2007
From: Jeff Dike <[EMAIL PROTECTED]>
Date: Fri, 23 Mar 2007 15:37:30 -0400
Subject: UML - host VDSO fix
To: [EMAIL PROTECTED]
Cc: uml-devel <user-mode-linux-devel@lists.sourceforge.net>
Message-ID: <[EMAIL PROTECTED]>
Content-Disposition: inline
From: Jeff Dike <[EMAIL PROTECTED]>
This fixes a problem seen by a number of people running UML on newer host
kernels. init would hang with an infinite segfault loop.
It turns out that the host kernel was providing a AT_SYSINFO_EHDR of
0xffffe000, which faked UML into believing that the host VDSO page could be
reused. However, AT_SYSINFO pointed into the middle of the address space, and
was unmapped as a result. Because UML was providing AT_SYSINFO_EHDR and
AT_SYSINFO to its own processes, these would branch to nowhere when trying to
use the VDSO.
The fix is to also check the location of AT_SYSINFO when deciding whether to
use the host's VDSO.
Signed-off-by: Jeff Dike <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
--- linux-2.6.17.orig/arch/um/os-Linux/elf_aux.c 2007-02-23
15:00:51.000000000 -0500
+++ linux-2.6.17/arch/um/os-Linux/elf_aux.c 2007-02-23 15:09:58.000000000
-0500
@@ -39,6 +39,9 @@ __init void scan_elf_aux( char **envp)
switch ( auxv->a_type ) {
case AT_SYSINFO:
__kernel_vsyscall = auxv->a_un.a_val;
+ /* See if the page is under TASK_SIZE */
+ if (__kernel_vsyscall < (unsigned long) envp)
+ __kernel_vsyscall = 0;
break;
case AT_SYSINFO_EHDR:
vsyscall_ehdr = auxv->a_un.a_val;
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Patches currently in stable-queue which might be from [EMAIL PROTECTED] are
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