[tip:x86/debug] x86/dumpstack: Honor supplied @regs arg - tip-bot for Andy Lutomirski

From: tip-bot for Andy Lutomirski <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: keescook@chromium.org, brgerst@gmail.com, tglx@linutronix.de,
	mingo@kernel.org, bp@alien8.de, torvalds@linux-foundation.org,
	luto@kernel.org, dvlasenk@redhat.com, fweisbec@gmail.com,
	hpa@zytor.com, bp@suse.de, jpoimboe@redhat.com,
	luto@amacapital.net, linux-kernel@vger.kernel.org,
	peterz@infradead.org, akpm@linux-foundation.org
Subject: [tip:x86/debug] x86/dumpstack: Honor supplied @regs arg
Date: Fri, 8 Jul 2016 05:07:35 -0700	[thread overview]
Message-ID: <tip-ef16dd0c2a523d2e3975bb1bea9f5727e3e7146f@git.kernel.org> (raw)
In-Reply-To: <efcd79bf4106d61f1cd258c2caa87f3a0618eeac.1466036668.git.luto@kernel.org>

Commit-ID:  ef16dd0c2a523d2e3975bb1bea9f5727e3e7146f
Gitweb:     http://git.kernel.org/tip/ef16dd0c2a523d2e3975bb1bea9f5727e3e7146f
Author:     Andy Lutomirski <luto@kernel.org>
AuthorDate: Tue, 5 Jul 2016 00:31:25 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 8 Jul 2016 11:33:18 +0200

x86/dumpstack: Honor supplied @regs arg

The comment suggests that show_stack(NULL, NULL) should backtrace the
current context, but the code doesn't match the comment. If regs are
given, start the "Stack:" hexdump at regs->sp.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1467671487-10344-2-git-send-email-bp@alien8.de
Link: http://lkml.kernel.org/r/efcd79bf4106d61f1cd258c2caa87f3a0618eeac.1466036668.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/dumpstack_32.c | 4 +++-
 arch/x86/kernel/dumpstack_64.c | 4 +++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index fef917e..948d77d 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -96,7 +96,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	int i;
 
 	if (sp == NULL) {
-		if (task)
+		if (regs)
+			sp = (unsigned long *)regs->sp;
+		else if (task)
 			sp = (unsigned long *)task->thread.sp;
 		else
 			sp = (unsigned long *)&sp;
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index d558a8a..a81e1ef 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -264,7 +264,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	 * back trace for this cpu:
 	 */
 	if (sp == NULL) {
-		if (task)
+		if (regs)
+			sp = (unsigned long *)regs->sp;
+		else if (task)
 			sp = (unsigned long *)task->thread.sp;
 		else
 			sp = (unsigned long *)&sp;
