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authorJeremy Fitzhardinge <jeremy@goop.org>2007-05-02 19:27:12 +0200
committerAndi Kleen <andi@basil.nowhere.org>2007-05-02 19:27:12 +0200
commit1dbf527c51c6c20c19869c8125cb5b87c3d09506 (patch)
treeab480b3eff886e54c6d3c881936f046599e7ea61 /Documentation
parentd4f7a2c18e59e0304a1c733589ce14fc02fec1bd (diff)
[PATCH] i386: Make COMPAT_VDSO runtime selectable.
Now that relocation of the VDSO for COMPAT_VDSO users is done at runtime rather than compile time, it is possible to enable/disable compat mode at runtime. This patch allows you to enable COMPAT_VDSO mode with "vdso=2" on the kernel command line, or via sysctl. (Switching on a running system shouldn't be done lightly; any process which was relying on the compat VDSO will be upset if it goes away.) The COMPAT_VDSO config option still exists, but if enabled it just makes vdso_enabled default to VDSO_COMPAT. +From: Hugh Dickins <hugh@veritas.com> Fix oops from i386-make-compat_vdso-runtime-selectable.patch. Even mingetty at system startup finds it easy to trigger an oops while reading /proc/PID/maps: though it has a good hold on the mm itself, that cannot stop exit_mm() from resetting tsk->mm to NULL. (It is usually show_map()'s call to get_gate_vma() which oopses, and I expect we could change that to check priv->tail_vma instead; but no matter, even m_start()'s call just after get_task_mm() is racy.) Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Zachary Amsden <zach@vmware.com> Cc: "Jan Beulich" <JBeulich@novell.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kernel-parameters.txt1
1 files changed, 1 insertions, 0 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 84c3bd05c63..4287696f18d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1820,6 +1820,7 @@ and is between 256 and 4096 characters. It is defined in the file
[USBHID] The interval which mice are to be polled at.
vdso= [IA-32,SH]
+ vdso=2: enable compat VDSO (default with COMPAT_VDSO)
vdso=1: enable VDSO (default)
vdso=0: disable VDSO mapping