Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755744Ab3CRVHI (ORCPT ); Mon, 18 Mar 2013 17:07:08 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:45638 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753713Ab3CRVHB (ORCPT ); Mon, 18 Mar 2013 17:07:01 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds Subject: [ 43/75] perf,x86: fix wrmsr_on_cpu() warning on suspend/resume Date: Mon, 18 Mar 2013 14:07:06 -0700 Message-Id: <20130318210513.351864601@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.2.434.g9a6c84e.dirty In-Reply-To: <20130318210510.203500214@linuxfoundation.org> References: <20130318210510.203500214@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1946 Lines: 52 3.8-stable review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 2a6e06b2aed6995af401dcd4feb5e79a0c7ea554 upstream. Commit 1d9d8639c063 ("perf,x86: fix kernel crash with PEBS/BTS after suspend/resume") fixed a crash when doing PEBS performance profiling after resuming, but in using init_debug_store_on_cpu() to restore the DS_AREA mtrr it also resulted in a new WARN_ON() triggering. init_debug_store_on_cpu() uses "wrmsr_on_cpu()", which in turn uses CPU cross-calls to do the MSR update. Which is not really valid at the early resume stage, and the warning is quite reasonable. Now, it all happens to _work_, for the simple reason that smp_call_function_single() ends up just doing the call directly on the CPU when the CPU number matches, but we really should just do the wrmsr() directly instead. This duplicates the wrmsr() logic, but hopefully we can just remove the wrmsr_on_cpu() version eventually. Reported-and-tested-by: Parag Warudkar Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/perf_event_intel_ds.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -732,8 +732,10 @@ void intel_ds_init(void) void perf_restore_debug_store(void) { + struct debug_store *ds = __this_cpu_read(cpu_hw_events.ds); + if (!x86_pmu.bts && !x86_pmu.pebs) return; - init_debug_store_on_cpu(smp_processor_id()); + wrmsrl(MSR_IA32_DS_AREA, (unsigned long)ds); } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/