From patchwork Thu Apr 2 19:13:29 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lee Jones X-Patchwork-Id: 228243 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CF37C2BA19 for ; Thu, 2 Apr 2020 19:13:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 149C72077D for ; Thu, 2 Apr 2020 19:13:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="y0yccAGl" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389214AbgDBTNL (ORCPT ); Thu, 2 Apr 2020 15:13:11 -0400 Received: from mail-wr1-f65.google.com ([209.85.221.65]:39037 "EHLO mail-wr1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389221AbgDBTNL (ORCPT ); Thu, 2 Apr 2020 15:13:11 -0400 Received: by mail-wr1-f65.google.com with SMTP id p10so5578621wrt.6 for ; Thu, 02 Apr 2020 12:13:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=EHjyrMQsUuQiUgFwWgDuTXyjroZXXjWL+Ehklr4usZQ=; b=y0yccAGlYmi6Gi2tDDZNJK+hdlPLjFTjyK7Gicaos7Uy8SclbzCA1ggfwUmwi6GKvf 1WyazXPVGAjnvrcl13yikAiF52t0CATVlBLfgVljpWzVx4ICqOBKTr3YW4+DzLVlT0yI 20VgIkqPlTOVmqMjuG16YqsN1MT/JFaWQ3r5Ui/Jn7nQlVt6DQbqTh063b7XYE7k4GAP R8SHrhvE6uwndALY+oj+RyDJYenggKDmljfgzXs2ay4eq+j+hH6c8Dq2zG/r9K8bCow7 OTAMQqozJ0T4g+yp5MaEY0z9fqGUfAzgo5cQFF81LOUIs14pYS3SiXZNPfVGsL6JRYU/ so2Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=EHjyrMQsUuQiUgFwWgDuTXyjroZXXjWL+Ehklr4usZQ=; b=FDW2OXR9X4BjrxaYK5uJm9BhEErGEXFwdTHFJxE0JWfeUOdW5AspWIWSSqITZbCDKC NFj75CfgD1lgZcm34VElUV3FM6HjrgrVOcsf00920UlHsQmA8XpzN02hTPl5mB7FAaTs frZ9WeTcd3fwOMO2RupJ0aH3zb7u56FmLZlb2FyXoR409j+ar5tbaYtw1PNvjJhUglbT PFMUGhd2yW+/xOYsHeGojZHlNCSwByVyLeznP8LB3srWlIh77MJFTdOi2T9fQZBwjnl7 JbAL9m6MxzIM1nfs6nxeei8reXgVdmlJAWZ10DXmrDAeZhXIh89tZ6ErNlvrwTxdXDJI sftg== X-Gm-Message-State: AGi0PubQbTLscWFEffPtMFNnxPjbeS12IZ+z3JUzkeOw9V3xY5THhrqy X960Hs18QJov1lBQibfNL+tnqMPp8rsQfQ== X-Google-Smtp-Source: APiQypLWh6M0XkTcXxzfX21ikP3NUPnNeaRcC5s5QCXKKvqe4a2C9dwVFC5dAMGvajDL4iCSkDbo1Q== X-Received: by 2002:a05:6000:1090:: with SMTP id y16mr4634087wrw.281.1585854788423; Thu, 02 Apr 2020 12:13:08 -0700 (PDT) Received: from localhost.localdomain ([95.149.164.95]) by smtp.gmail.com with ESMTPSA id y12sm5511514wrn.55.2020.04.02.12.13.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Apr 2020 12:13:07 -0700 (PDT) From: Lee Jones To: stable@vger.kernel.org Subject: [PATCH 4.14 09/33] arm64: traps: Don't print stack or raw PC/LR values in backtraces Date: Thu, 2 Apr 2020 20:13:29 +0100 Message-Id: <20200402191353.787836-9-lee.jones@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200402191353.787836-1-lee.jones@linaro.org> References: <20200402191353.787836-1-lee.jones@linaro.org> MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Will Deacon [ Upstream commit a25ffd3a6302a67814280274d8f1aa4ae2ea4b59 ] Printing raw pointer values in backtraces has potential security implications and are of questionable value anyway. This patch follows x86's lead and removes the "Exception stack:" dump from kernel backtraces, as well as converting PC/LR values to symbols such as "sysrq_handle_crash+0x20/0x30". Tested-by: Laura Abbott Signed-off-by: Will Deacon Signed-off-by: Lee Jones --- arch/arm64/kernel/process.c | 8 ++--- arch/arm64/kernel/traps.c | 65 ++----------------------------------- 2 files changed, 6 insertions(+), 67 deletions(-) diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 243fd247d04e0..4cbf571f428cd 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -186,11 +186,9 @@ void __show_regs(struct pt_regs *regs) } show_regs_print_info(KERN_DEFAULT); - print_symbol("PC is at %s\n", instruction_pointer(regs)); - print_symbol("LR is at %s\n", lr); - printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", - regs->pc, lr, regs->pstate); - printk("sp : %016llx\n", sp); + print_symbol("pc : %s\n", regs->pc); + print_symbol("lr : %s\n", lr); + printk("sp : %016llx pstate : %08llx\n", sp, regs->pstate); i = top_reg; diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5ae9c86c30d1d..b30d23431fe11 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -59,55 +59,9 @@ static const char *handler[]= { int show_unhandled_signals = 0; -/* - * Dump out the contents of some kernel memory nicely... - */ -static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top) -{ - unsigned long first; - mm_segment_t fs; - int i; - - /* - * We need to switch to kernel mode so that we can use __get_user - * to safely read from kernel space. - */ - fs = get_fs(); - set_fs(KERNEL_DS); - - printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); - - for (first = bottom & ~31; first < top; first += 32) { - unsigned long p; - char str[sizeof(" 12345678") * 8 + 1]; - - memset(str, ' ', sizeof(str)); - str[sizeof(str) - 1] = '\0'; - - for (p = first, i = 0; i < (32 / 8) - && p < top; i++, p += 8) { - if (p >= bottom && p < top) { - unsigned long val; - - if (__get_user(val, (unsigned long *)p) == 0) - sprintf(str + i * 17, " %016lx", val); - else - sprintf(str + i * 17, " ????????????????"); - } - } - printk("%s%04lx:%s\n", lvl, first & 0xffff, str); - } - - set_fs(fs); -} - static void dump_backtrace_entry(unsigned long where) { - /* - * Note that 'where' can have a physical address, but it's not handled. - */ - print_ip_sym(where); + printk(" %pS\n", (void *)where); } static void __dump_instr(const char *lvl, struct pt_regs *regs) @@ -177,10 +131,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) #endif printk("Call trace:\n"); - while (1) { - unsigned long stack; - int ret; - + do { /* skip until specified stack frame */ if (!skip) { dump_backtrace_entry(frame.pc); @@ -195,17 +146,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) */ dump_backtrace_entry(regs->pc); } - ret = unwind_frame(tsk, &frame); - if (ret < 0) - break; - if (in_entry_text(frame.pc)) { - stack = frame.fp - offsetof(struct pt_regs, stackframe); - - if (on_accessible_stack(tsk, stack)) - dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs)); - } - } + } while (!unwind_frame(tsk, &frame)); put_task_stack(tsk); }