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authorLinus Torvalds <torvalds@linux-foundation.org>2016-07-25 18:18:04 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-25 18:18:04 -0700
commit36e635cb21d96da0f30b91a39cc95ef4ed1bce26 (patch)
treec28397756f579bbd23f1570ca612772c02cfbab2
parentc265cc5c3cb2e950910437a846ef59e3a5c2df51 (diff)
parent81c2949f7fdcf8ff681326669afde24962232670 (diff)
downloadlinux-36e635cb21d96da0f30b91a39cc95ef4ed1bce26.tar.bz2
Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 stackdump update from Ingo Molnar: "A number of stackdump enhancements" * 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/dumpstack: Add show_stack_regs() and use it printk: Make the printk*once() variants return a value x86/dumpstack: Honor supplied @regs arg
-rw-r--r--arch/x86/include/asm/kdebug.h1
-rw-r--r--arch/x86/kernel/dumpstack.c5
-rw-r--r--arch/x86/kernel/dumpstack_32.c4
-rw-r--r--arch/x86/kernel/dumpstack_64.c4
-rw-r--r--arch/x86/mm/extable.c13
-rw-r--r--include/linux/printk.h17
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 de8242d8bb61..92e8f0a7159c 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -205,6 +205,11 @@ 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 2552a1eadfed..6dede08dd98b 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 0f90cc218d04..832b98f822be 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, ...) \