From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756182Ab3KLUTD (ORCPT ); Tue, 12 Nov 2013 15:19:03 -0500 Received: from terminus.zytor.com ([198.137.202.10]:38259 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755541Ab3KLUSx (ORCPT ); Tue, 12 Nov 2013 15:18:53 -0500 Date: Tue, 12 Nov 2013 12:18:26 -0800 From: tip-bot for Jiri Slaby Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, namhyung@gmail.com, jslaby@suse.cz, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, jslaby@suse.cz, namhyung@gmail.com, fweisbec@gmail.com, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1382706418-8435-1-git-send-email-jslaby@suse.cz> References: <1382706418-8435-1-git-send-email-jslaby@suse.cz> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/urgent] x86/dumpstack: Fix printk_address for direct addresses Git-Commit-ID: 5f01c98859073cb512b01d4fad74b5f4e047be0b 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 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.1 (terminus.zytor.com [127.0.0.1]); Tue, 12 Nov 2013 12:18:33 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 5f01c98859073cb512b01d4fad74b5f4e047be0b Gitweb: http://git.kernel.org/tip/5f01c98859073cb512b01d4fad74b5f4e047be0b Author: Jiri Slaby AuthorDate: Fri, 25 Oct 2013 15:06:58 +0200 Committer: Ingo Molnar CommitDate: Tue, 12 Nov 2013 21:06:06 +0100 x86/dumpstack: Fix printk_address for direct addresses Consider a kernel crash in a module, simulated the following way: static int my_init(void) { char *map = (void *)0x5; *map = 3; return 0; } module_init(my_init); When we turn off FRAME_POINTERs, the very first instruction in that function causes a BUG. The problem is that we print IP in the BUG report using %pB (from printk_address). And %pB decrements the pointer by one to fix printing addresses of functions with tail calls. This was added in commit 71f9e59800e5ad4 ("x86, dumpstack: Use %pB format specifier for stack trace") to fix the call stack printouts. So instead of correct output: BUG: unable to handle kernel NULL pointer dereference at 0000000000000005 IP: [] my_init+0x0/0x10 [pb173] We get: BUG: unable to handle kernel NULL pointer dereference at 0000000000000005 IP: [] 0xffffffffa0151fff To fix that, we use %pS only for stack addresses printouts (via newly added printk_stack_address) and %pB for regs->ip (via printk_address). I.e. we revert to the old behaviour for all except call stacks. And since from all those reliable is 1, we remove that parameter from printk_address. Signed-off-by: Jiri Slaby Cc: Namhyung Kim Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: joe@perches.com Cc: jirislaby@gmail.com Link: http://lkml.kernel.org/r/1382706418-8435-1-git-send-email-jslaby@suse.cz Signed-off-by: Ingo Molnar --- arch/x86/include/asm/kdebug.h | 2 +- arch/x86/kernel/dumpstack.c | 11 ++++++++--- arch/x86/kernel/process_64.c | 2 +- arch/x86/mm/fault.c | 2 +- arch/x86/platform/uv/uv_nmi.c | 2 +- 5 files changed, 12 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h index 2c37aad..32ce713 100644 --- a/arch/x86/include/asm/kdebug.h +++ b/arch/x86/include/asm/kdebug.h @@ -21,7 +21,7 @@ enum die_val { DIE_NMIUNKNOWN, }; -extern void printk_address(unsigned long address, int reliable); +extern void printk_address(unsigned long address); extern void die(const char *, struct pt_regs *,long); extern int __must_check __die(const char *, struct pt_regs *, long); extern void show_trace(struct task_struct *t, struct pt_regs *regs, diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c index deb6421..d9c12d3 100644 --- a/arch/x86/kernel/dumpstack.c +++ b/arch/x86/kernel/dumpstack.c @@ -25,12 +25,17 @@ unsigned int code_bytes = 64; int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE; static int die_counter; -void printk_address(unsigned long address, int reliable) +static void printk_stack_address(unsigned long address, int reliable) { pr_cont(" [<%p>] %s%pB\n", (void *)address, reliable ? "" : "? ", (void *)address); } +void printk_address(unsigned long address) +{ + pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address); +} + #ifdef CONFIG_FUNCTION_GRAPH_TRACER static void print_ftrace_graph_addr(unsigned long addr, void *data, @@ -151,7 +156,7 @@ static void print_trace_address(void *data, unsigned long addr, int reliable) { touch_nmi_watchdog(); printk(data); - printk_address(addr, reliable); + printk_stack_address(addr, reliable); } static const struct stacktrace_ops print_trace_ops = { @@ -281,7 +286,7 @@ int __kprobes __die(const char *str, struct pt_regs *regs, long err) #else /* Executive summary in case the oops scrolled away */ printk(KERN_ALERT "RIP "); - printk_address(regs->ip, 1); + printk_address(regs->ip); printk(" RSP <%016lx>\n", regs->sp); #endif return 0; diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 45ab4d6..176ad94 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -63,7 +63,7 @@ void __show_regs(struct pt_regs *regs, int all) unsigned int ds, cs, es; printk(KERN_DEFAULT "RIP: %04lx:[<%016lx>] ", regs->cs & 0xffff, regs->ip); - printk_address(regs->ip, 1); + printk_address(regs->ip); printk(KERN_DEFAULT "RSP: %04lx:%016lx EFLAGS: %08lx\n", regs->ss, regs->sp, regs->flags); printk(KERN_DEFAULT "RAX: %016lx RBX: %016lx RCX: %016lx\n", diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 7a517bb..e7e1cac 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -596,7 +596,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long error_code, printk(KERN_CONT " at %p\n", (void *) address); printk(KERN_ALERT "IP:"); - printk_address(regs->ip, 1); + printk_address(regs->ip); dump_pagetable(address); } diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c index 2e863ad..8eeccba 100644 --- a/arch/x86/platform/uv/uv_nmi.c +++ b/arch/x86/platform/uv/uv_nmi.c @@ -399,7 +399,7 @@ static void uv_nmi_dump_cpu_ip(int cpu, struct pt_regs *regs) printk(KERN_DEFAULT "UV: %4d %6d %-32.32s ", cpu, current->pid, current->comm); - printk_address(regs->ip, 1); + printk_address(regs->ip); } /* Dump this cpu's state */