x86: disable X86_PTRACE_BTS for now

upstream commit: d45b41ae8da0f54aec0eebcc6f893ba5f22a1e8e

Oleg Nesterov found a couple of races in the ptrace-bts code
and fixes are queued up for it but they did not get ready in time
for the merge window. We'll merge them in v2.6.31 - until then
mark the feature as CONFIG_BROKEN. There's no user-space yet
making use of this so it's not a big issue.

Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[chrisw: trivial 2.6.29 backport]
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index c98d52e82966f9a965b4b2ddc2af2e1272bea7b2..6ed3aca7dd414bd97070c1e2dbe8e54d48d13d08 100644 (file)
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -523,6 +523,7 @@ config X86_PTRACE_BTS
        bool "Branch Trace Store"
        default y
        depends on X86_DEBUGCTLMSR
+       depends on BROKEN
        help
          This adds a ptrace interface to the hardware's branch trace store.