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Message-ID: <20160725153032.GA5332@gmail.com>
Date: Mon, 25 Jul 2016 17:30:32 +0200
From: Ingo Molnar <mingo@...nel.org>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/debug changes for v4.8
Linus,
Please pull the latest x86-debug-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-debug-for-linus
# HEAD: 81c2949f7fdcf8ff681326669afde24962232670 x86/dumpstack: Add show_stack_regs() and use it
A number of stackdump enhancements.
out-of-topic modifications in x86-debug-for-linus:
----------------------------------------------------
include/linux/printk.h # 069f0cd00df0: printk: Make the printk*once
Thanks,
Ingo
------------------>
Andy Lutomirski (1):
x86/dumpstack: Honor supplied @regs arg
Borislav Petkov (2):
printk: Make the printk*once() variants return a value
x86/dumpstack: Add show_stack_regs() and use it
arch/x86/include/asm/kdebug.h | 1 +
arch/x86/kernel/dumpstack.c | 5 +++++
arch/x86/kernel/dumpstack_32.c | 4 +++-
arch/x86/kernel/dumpstack_64.c | 4 +++-
arch/x86/mm/extable.c | 13 ++++++++-----
include/linux/printk.h | 17 ++++++++++++-----
6 files changed, 32 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
index e5f5dc9787d5..1ef9d581b5d9 100644
--- a/arch/x86/include/asm/kdebug.h
+++ b/arch/x86/include/asm/kdebug.h
@@ -26,6 +26,7 @@ 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,
unsigned long *sp, unsigned long bp);
+extern void show_stack_regs(struct pt_regs *regs);
extern void __show_regs(struct pt_regs *regs, int all);
extern unsigned long oops_begin(void);
extern void oops_end(unsigned long, struct pt_regs *, int signr);
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ef8017ca5ba9..d66e5ac823b2 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -197,6 +197,11 @@ void show_stack(struct task_struct *task, unsigned long *sp)
show_stack_log_lvl(task, NULL, sp, bp, "");
}
+void show_stack_regs(struct pt_regs *regs)
+{
+ show_stack_log_lvl(current, regs, (unsigned long *)regs->sp, regs->bp, "");
+}
+
static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
static int die_owner = -1;
static unsigned int die_nest_count;
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index fef917e79b9d..948d77da3881 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 d558a8a49016..a81e1ef73bf2 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;
diff --git a/arch/x86/mm/extable.c b/arch/x86/mm/extable.c
index 4bb53b89f3c5..fafc771568c7 100644
--- a/arch/x86/mm/extable.c
+++ b/arch/x86/mm/extable.c
@@ -1,6 +1,7 @@
#include <linux/module.h>
#include <asm/uaccess.h>
#include <asm/traps.h>
+#include <asm/kdebug.h>
typedef bool (*ex_handler_t)(const struct exception_table_entry *,
struct pt_regs *, int);
@@ -46,8 +47,9 @@ EXPORT_SYMBOL(ex_handler_ext);
bool ex_handler_rdmsr_unsafe(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
- WARN_ONCE(1, "unchecked MSR access error: RDMSR from 0x%x\n",
- (unsigned int)regs->cx);
+ if (pr_warn_once("unchecked MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pF)\n",
+ (unsigned int)regs->cx, regs->ip, (void *)regs->ip))
+ show_stack_regs(regs);
/* Pretend that the read succeeded and returned 0. */
regs->ip = ex_fixup_addr(fixup);
@@ -60,9 +62,10 @@ EXPORT_SYMBOL(ex_handler_rdmsr_unsafe);
bool ex_handler_wrmsr_unsafe(const struct exception_table_entry *fixup,
struct pt_regs *regs, int trapnr)
{
- WARN_ONCE(1, "unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x)\n",
- (unsigned int)regs->cx,
- (unsigned int)regs->dx, (unsigned int)regs->ax);
+ if (pr_warn_once("unchecked MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pF)\n",
+ (unsigned int)regs->cx, (unsigned int)regs->dx,
+ (unsigned int)regs->ax, regs->ip, (void *)regs->ip))
+ show_stack_regs(regs);
/* Pretend that the write succeeded. */
regs->ip = ex_fixup_addr(fixup);
diff --git a/include/linux/printk.h b/include/linux/printk.h
index f4da695fd615..f136b22c7772 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -108,11 +108,14 @@ struct va_format {
* Dummy printk for disabled debugging statements to use whilst maintaining
* gcc's format checking.
*/
-#define no_printk(fmt, ...) \
-do { \
- if (0) \
- printk(fmt, ##__VA_ARGS__); \
-} while (0)
+#define no_printk(fmt, ...) \
+({ \
+ do { \
+ if (0) \
+ printk(fmt, ##__VA_ARGS__); \
+ } while (0); \
+ 0; \
+})
#ifdef CONFIG_EARLY_PRINTK
extern asmlinkage __printf(1, 2)
@@ -309,20 +312,24 @@ extern asmlinkage void dump_stack(void) __cold;
#define printk_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk(fmt, ##__VA_ARGS__); \
} \
+ unlikely(__ret_print_once); \
})
#define printk_deferred_once(fmt, ...) \
({ \
static bool __print_once __read_mostly; \
+ bool __ret_print_once = !__print_once; \
\
if (!__print_once) { \
__print_once = true; \
printk_deferred(fmt, ##__VA_ARGS__); \
} \
+ unlikely(__ret_print_once); \
})
#else
#define printk_once(fmt, ...) \
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