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[209.132.180.67]) by mx.google.com with ESMTP id d39si22853590pla.304.2019.04.15.12.26.53; Mon, 15 Apr 2019 12:26:53 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=u1PHUEMf; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729525AbfDOTEW (ORCPT + 30 others); Mon, 15 Apr 2019 15:04:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:37168 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729513AbfDOTET (ORCPT ); Mon, 15 Apr 2019 15:04:19 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 60E5421900; Mon, 15 Apr 2019 19:04:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1555355058; bh=5Et1N5ymEUid78bkME3Qf+QTEQkNLZk0kbPTYggib8M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u1PHUEMfFEVXhpci5qQS3yO/t3+B2/lAIJklmnv4NA27r6ID5zysbcPeigxdLSEzd 1isnHzWgncLMJ5DxBiFzFKw8ojdcl86gMkKgewHVhnrfYAP7Mwv9BwubSLfN4XgwTk PhNzj+DUvGXBSWJJhMiZasMtyg5YLr77pJVAzyHs= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kefeng Wang , Will Deacon Subject: [PATCH 4.14 59/69] arm64: backtrace: Dont bother trying to unwind the userspace stack Date: Mon, 15 Apr 2019 20:59:17 +0200 Message-Id: <20190415183735.551119463@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190415183726.036654568@linuxfoundation.org> References: <20190415183726.036654568@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Will Deacon commit 1e6f5440a6814d28c32d347f338bfef68bc3e69d upstream. Calling dump_backtrace() with a pt_regs argument corresponding to userspace doesn't make any sense and our unwinder will simply print "Call trace:" before unwinding the stack looking for user frames. Rather than go through this song and dance, just return early if we're passed a user register state. Cc: Fixes: 1149aad10b1e ("arm64: Add dump_backtrace() in show_regs") Reported-by: Kefeng Wang Signed-off-by: Will Deacon Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/traps.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -145,10 +145,16 @@ static void dump_instr(const char *lvl, void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) { struct stackframe frame; - int skip; + int skip = 0; pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); + if (regs) { + if (user_mode(regs)) + return; + skip = 1; + } + if (!tsk) tsk = current; @@ -169,7 +175,6 @@ void dump_backtrace(struct pt_regs *regs frame.graph = tsk->curr_ret_stack; #endif - skip = !!regs; printk("Call trace:\n"); while (1) { unsigned long stack; @@ -232,15 +237,13 @@ static int __die(const char *str, int er return ret; print_modules(); - __show_regs(regs); pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk)); + show_regs(regs); - if (!user_mode(regs)) { - dump_backtrace(regs, tsk); + if (!user_mode(regs)) dump_instr(KERN_EMERG, regs); - } return ret; }