linux-kernel - [PATCH 5/6] x86/dumpstack: remove unnecessary stack pointer arguments

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Message-Id: <1694e2e955e3b9a73a3c3d5ba2634344014dd550.1472057064.git.jpoimboe@redhat.com>
Date:   Wed, 24 Aug 2016 11:50:18 -0500
From:   Josh Poimboeuf <jpoimboe@...hat.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        Andy Lutomirski <luto@...capital.net>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Brian Gerst <brgerst@...il.com>,
        Kees Cook <keescook@...omium.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Frederic Weisbecker <fweisbec@...il.com>,
        Byungchul Park <byungchul.park@....com>,
        Nilay Vaish <nilayvaish@...il.com>
Subject: [PATCH 5/6] x86/dumpstack: remove unnecessary stack pointer arguments

When calling show_stack_log_lvl() or dump_trace() with a regs argument,
providing a stack pointer or frame pointer is redundant.

Reviewed-by: Andy Lutomirski <luto@...nel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>d
---
 arch/x86/kernel/dumpstack.c    | 2 +-
 arch/x86/kernel/dumpstack_32.c | 2 +-
 arch/x86/kernel/dumpstack_64.c | 5 +----
 arch/x86/oprofile/backtrace.c  | 5 +----
 4 files changed, 4 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 6d6f468..c6c6c39 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -185,7 +185,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 
 void show_stack_regs(struct pt_regs *regs)
 {
-	show_stack_log_lvl(current, regs, (unsigned long *)regs->sp, regs->bp, "");
+	show_stack_log_lvl(current, regs, NULL, 0, "");
 }
 
 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 358fe1c..c533b8b 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -122,7 +122,7 @@ void show_regs(struct pt_regs *regs)
 		u8 *ip;
 
 		pr_emerg("Stack:\n");
-		show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
+		show_stack_log_lvl(NULL, regs, NULL, 0, KERN_EMERG);
 
 		pr_emerg("Code:");
 
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 7f3b806..b243352 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -283,9 +283,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 void show_regs(struct pt_regs *regs)
 {
 	int i;
-	unsigned long sp;
 
-	sp = regs->sp;
 	show_regs_print_info(KERN_DEFAULT);
 	__show_regs(regs, 1);
 
@@ -300,8 +298,7 @@ void show_regs(struct pt_regs *regs)
 		u8 *ip;
 
 		printk(KERN_DEFAULT "Stack:\n");
-		show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
-				   0, KERN_DEFAULT);
+		show_stack_log_lvl(NULL, regs, NULL, 0, KERN_DEFAULT);
 
 		printk(KERN_DEFAULT "Code: ");
 
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c
index 2ef6c8b..d950f9e 100644
--- a/arch/x86/oprofile/backtrace.c
+++ b/arch/x86/oprofile/backtrace.c
@@ -113,8 +113,6 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
 	struct stack_frame *head = (struct stack_frame *)frame_pointer(regs);
 
 	if (!user_mode(regs)) {
-		unsigned long stack = kernel_stack_pointer(regs);
-
 		if (!depth)
 			return;
 
@@ -122,8 +120,7 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth)
 		if (!--depth)
 			return;
 
-		dump_trace(NULL, regs, (unsigned long *)stack, 0,
-			   &backtrace_ops, &depth);
+		dump_trace(NULL, regs, NULL, 0, &backtrace_ops, &depth);
 		return;
 	}
 
-- 
2.7.4