From: Ingo Molnar Date: Wed, 24 Dec 2008 09:49:51 +0000 (+0100) Subject: x86: disable X86_PTRACE_BTS X-Git-Tag: v2.6.28~2^2 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?p=linux-2.6-omap-h63xx.git;a=commitdiff_plain;h=40f15ad8aadff5ebb621b17a6f303ad2cd3f847d x86: disable X86_PTRACE_BTS there's a new ptrace arch level feature in .28: config X86_PTRACE_BTS bool "Branch Trace Store" it has broken fork() handling: the old DS area gets copied over into a new task without clearing it. Fixes exist but they came too late: c5dee61: x86, bts: memory accounting bf53de9: x86, bts: add fork and exit handling and are queued up for v2.6.29. This shows that the facility is still not tested well enough to release into a stable kernel - disable it for now and reactivate in .29. In .29 the hardware-branch-tracer will use the DS/BTS facilities too - hopefully resulting in better code. Signed-off-by: Ingo Molnar --- diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index b815664fe37..8e99073b9e0 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -520,6 +520,7 @@ 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.