From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752063AbdKHJue (ORCPT ); Wed, 8 Nov 2017 04:50:34 -0500 Received: from terminus.zytor.com ([65.50.211.136]:53929 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbdKHJu3 (ORCPT ); Wed, 8 Nov 2017 04:50:29 -0500 Date: Wed, 8 Nov 2017 01:46:52 -0800 From: tip-bot for Josh Poimboeuf Message-ID: Cc: mingo@kernel.org, torvalds@linux-foundation.org, bauerman@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, peterz@infradead.org, hpa@zytor.com, jpoimboe@redhat.com, fengguang.wu@intel.com Reply-To: jpoimboe@redhat.com, fengguang.wu@intel.com, peterz@infradead.org, hpa@zytor.com, tglx@linutronix.de, bauerman@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, mingo@kernel.org In-Reply-To: <20171108021934.zbl6unh5hpugybc5@treble> References: <20171108021934.zbl6unh5hpugybc5@treble> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/unwind: Disable KASAN checking in the ORC unwinder Git-Commit-ID: 881125bfe65bb772f34f4fcb04a35dfe117e186a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 881125bfe65bb772f34f4fcb04a35dfe117e186a Gitweb: https://git.kernel.org/tip/881125bfe65bb772f34f4fcb04a35dfe117e186a Author: Josh Poimboeuf AuthorDate: Tue, 7 Nov 2017 20:19:34 -0600 Committer: Ingo Molnar CommitDate: Wed, 8 Nov 2017 10:21:49 +0100 x86/unwind: Disable KASAN checking in the ORC unwinder Fengguang reported a KASAN warning: Kprobe smoke test: started ================================================================== BUG: KASAN: stack-out-of-bounds in deref_stack_reg+0xb5/0x11a Read of size 8 at addr ffff8800001c7cd8 by task swapper/1 CPU: 0 PID: 1 Comm: swapper Not tainted 4.14.0-rc8 #26 Call Trace: <#DB> ... save_trace+0xd9/0x1d3 mark_lock+0x5f7/0xdc3 __lock_acquire+0x6b4/0x38ef lock_acquire+0x1a1/0x2aa _raw_spin_lock_irqsave+0x46/0x55 kretprobe_table_lock+0x1a/0x42 pre_handler_kretprobe+0x3f5/0x521 kprobe_int3_handler+0x19c/0x25f do_int3+0x61/0x142 int3+0x30/0x60 [...] The ORC unwinder got confused by some kprobes changes, which isn't surprising since the runtime code no longer matches vmlinux and the stack was modified for kretprobes. Until we have a way for generated code to register changes with the unwinder, these types of warnings are inevitable. So just disable KASAN checks for stack accesses in the ORC unwinder. Reported-by: Fengguang Wu Signed-off-by: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thiago Jung Bauermann Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20171108021934.zbl6unh5hpugybc5@treble Signed-off-by: Ingo Molnar --- arch/x86/kernel/unwind_orc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/unwind_orc.c b/arch/x86/kernel/unwind_orc.c index b95007e..a3f973b 100644 --- a/arch/x86/kernel/unwind_orc.c +++ b/arch/x86/kernel/unwind_orc.c @@ -279,7 +279,7 @@ static bool deref_stack_reg(struct unwind_state *state, unsigned long addr, if (!stack_access_ok(state, addr, sizeof(long))) return false; - *val = READ_ONCE_TASK_STACK(state->task, *(unsigned long *)addr); + *val = READ_ONCE_NOCHECK(*(unsigned long *)addr); return true; }