From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Alexander Shishkin To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel@vger.kernel.org, vince@deater.net, eranian@google.com, Arnaldo Carvalho de Melo , Alexander Shishkin , stable@vger.kernel.org#4.7 Subject: [PATCH 2/3] perf/x86: Tighten up the kernel_ip() check Date: Thu, 15 Sep 2016 16:29:43 +0300 Message-Id: <20160915132944.10331-3-alexander.shishkin@linux.intel.com> In-Reply-To: <20160915132944.10331-1-alexander.shishkin@linux.intel.com> References: <20160915132944.10331-1-alexander.shishkin@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: The kernel_ip() filter is used mostly by the DS/LBR code to look at the branch addresses, but Intel PT also uses it to validate the address filter offsets for kernel addresses, for which it is not sufficient: supplying something in bits 64:48 that's not a sign extension of the lower address bits (like 0xf00d000000000000) throws a #GP. In the interest of improving everybody's kernel address checks, this patch adds address validation to kernel_ip(). Cc: stable@vger.kernel.org # 4.7 Reported-by: Adrian Hunter Signed-off-by: Alexander Shishkin --- arch/x86/events/perf_event.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index 5874d8de1f..88fb389356 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -783,7 +783,7 @@ static inline bool kernel_ip(unsigned long ip) #ifdef CONFIG_X86_32 return ip > PAGE_OFFSET; #else - return (long)ip < 0; + return (long)ip < 0 && virt_addr_valid(ip); #endif } -- 2.9.3