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x86/dumpstack: Add get_stack_info() interface 

valid_stack_ptr() is buggy: it assumes that all stacks are of size
THREAD_SIZE, which is not true for exception stacks.  So the
walk_stack() callbacks will need to know the location of the beginning
of the stack as well as the end.

Another issue is that in general the various features of a stack (type,
size, next stack pointer, description string) are scattered around in
various places throughout the stack dump code.

Encapsulate all that information in a single place with a new stack_info
struct and a get_stack_info() interface.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nilay Vaish <nilayvaish@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/8164dd0db96b7e6a279fa17ae5e6dc375eecb4a9.1473905218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Josh Poimboeuf 2016-09-14 21:07:42 -05:00 committed by Ingo Molnar
parent 9c00390757
commit cb76c93982
7 changed files with 238 additions and 132 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/events/core.c
View File

@ -2251,7 +2251,7 @@ void arch_perf_update_userpage(struct perf_event *event,
* callchain support
*/
static int backtrace_stack(void *data, char *name)
static int backtrace_stack(void *data, const char *name)
{
return 0;
}

41
arch/x86/include/asm/stacktrace.h
View File

@ -10,6 +10,39 @@
#include <linux/ptrace.h>
#include <asm/switch_to.h>
enum stack_type {
STACK_TYPE_UNKNOWN,
STACK_TYPE_TASK,
STACK_TYPE_IRQ,
STACK_TYPE_SOFTIRQ,
STACK_TYPE_EXCEPTION,
STACK_TYPE_EXCEPTION_LAST = STACK_TYPE_EXCEPTION + N_EXCEPTION_STACKS-1,
};
struct stack_info {
enum stack_type type;
unsigned long *begin, *end, *next_sp;
};
bool in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info);
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask);
void stack_type_str(enum stack_type type, const char **begin,
const char **end);
static inline bool on_stack(struct stack_info *info, void *addr, size_t len)
{
void *begin = info->begin;
void *end = info->end;
return (info->type != STACK_TYPE_UNKNOWN &&
addr >= begin && addr < end &&
addr + len > begin && addr + len <= end);
}
extern int kstack_depth_to_print;
struct thread_info;
@ -20,27 +53,27 @@ typedef unsigned long (*walk_stack_t)(struct task_struct *task,
unsigned long bp,
const struct stacktrace_ops *ops,
void *data,
unsigned long *end,
struct stack_info *info,
int *graph);
extern unsigned long
print_context_stack(struct task_struct *task,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data,
unsigned long *end, int *graph);
struct stack_info *info, int *graph);
extern unsigned long
print_context_stack_bp(struct task_struct *task,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data,
unsigned long *end, int *graph);
struct stack_info *info, int *graph);
/* Generic stack tracer with callbacks */
struct stacktrace_ops {
int (*address)(void *data, unsigned long address, int reliable);
/* On negative return stop dumping */
int (*stack)(void *data, char *name);
int (*stack)(void *data, const char *name);
walk_stack_t walk_stack;
};

40
arch/x86/kernel/dumpstack.c
View File

@ -25,6 +25,23 @@ unsigned int code_bytes = 64;
int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
static int die_counter;
bool in_task_stack(unsigned long *stack, struct task_struct *task,
struct stack_info *info)
{
unsigned long *begin = task_stack_page(task);
unsigned long *end = task_stack_page(task) + THREAD_SIZE;
if (stack < begin || stack >= end)
return false;
info->type = STACK_TYPE_TASK;
info->begin = begin;
info->end = end;
info->next_sp = NULL;
return true;
}
static void printk_stack_address(unsigned long address, int reliable,
char *log_lvl)
{
@ -46,24 +63,11 @@ void printk_address(unsigned long address)
* severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
*/
static inline int valid_stack_ptr(struct task_struct *task,
void *p, unsigned int size, void *end)
{
void *t = task_stack_page(task);
if (end) {
if (p < end && p >= (end-THREAD_SIZE))
return 1;
else
return 0;
}
return p >= t && p < t + THREAD_SIZE - size;
}
unsigned long
print_context_stack(struct task_struct *task,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data,
unsigned long *end, int *graph)
struct stack_info *info, int *graph)
{
struct stack_frame *frame = (struct stack_frame *)bp;
@ -75,7 +79,7 @@ print_context_stack(struct task_struct *task,
PAGE_SIZE)
stack = (unsigned long *)task_stack_page(task);
while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
while (on_stack(info, stack, sizeof(*stack))) {
unsigned long addr = *stack;
if (__kernel_text_address(addr)) {
@ -114,12 +118,12 @@ unsigned long
print_context_stack_bp(struct task_struct *task,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data,
unsigned long *end, int *graph)
struct stack_info *info, int *graph)
{
struct stack_frame *frame = (struct stack_frame *)bp;
unsigned long *retp = &frame->return_address;
while (valid_stack_ptr(task, retp, sizeof(*retp), end)) {
while (on_stack(info, stack, sizeof(*stack) * 2)) {
unsigned long addr = *retp;
unsigned long real_addr;
@ -138,7 +142,7 @@ print_context_stack_bp(struct task_struct *task,
}
EXPORT_SYMBOL_GPL(print_context_stack_bp);
static int print_trace_stack(void *data, char *name)
static int print_trace_stack(void *data, const char *name)
{
printk("%s <%s> ", (char *)data, name);
return 0;

110
arch/x86/kernel/dumpstack_32.c
View File

@ -16,61 +16,117 @@
#include <asm/stacktrace.h>
static void *is_irq_stack(void *p, void *irq)
void stack_type_str(enum stack_type type, const char **begin, const char **end)
{
if (p < irq || p >= (irq + THREAD_SIZE))
return NULL;
return irq + THREAD_SIZE;
switch (type) {
case STACK_TYPE_IRQ:
case STACK_TYPE_SOFTIRQ:
*begin = "IRQ";
*end = "EOI";
break;
default:
*begin = NULL;
*end = NULL;
}
}
static void *is_hardirq_stack(unsigned long *stack)
static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
{
void *irq = this_cpu_read(hardirq_stack);
unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
return is_irq_stack(stack, irq);
if (stack < begin || stack >= end)
return false;
info->type = STACK_TYPE_IRQ;
info->begin = begin;
info->end = end;
/*
* See irq_32.c -- the next stack pointer is stored at the beginning of
* the stack.
*/
info->next_sp = (unsigned long *)*begin;
return true;
}
static void *is_softirq_stack(unsigned long *stack)
static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
{
void *irq = this_cpu_read(softirq_stack);
unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
return is_irq_stack(stack, irq);
if (stack < begin || stack >= end)
return false;
info->type = STACK_TYPE_SOFTIRQ;
info->begin = begin;
info->end = end;
/*
* The next stack pointer is stored at the beginning of the stack.
* See irq_32.c.
*/
info->next_sp = (unsigned long *)*begin;
return true;
}
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask)
{
if (!stack)
goto unknown;
task = task ? : current;
if (in_task_stack(stack, task, info))
return 0;
if (task != current)
goto unknown;
if (in_hardirq_stack(stack, info))
return 0;
if (in_softirq_stack(stack, info))
return 0;
unknown:
info->type = STACK_TYPE_UNKNOWN;
return -EINVAL;
}
void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
unsigned long visit_mask = 0;
int graph = 0;
u32 *prev_esp;
task = task ? : current;
stack = stack ? : get_stack_pointer(task, regs);
bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
for (;;) {
void *end_stack;
const char *begin_str, *end_str;
struct stack_info info;
end_stack = is_hardirq_stack(stack);
if (!end_stack)
end_stack = is_softirq_stack(stack);
bp = ops->walk_stack(task, stack, bp, ops, data,
end_stack, &graph);
/* Stop if not on irq stack */
if (!end_stack)
if (get_stack_info(stack, task, &info, &visit_mask))
break;
/* The previous esp is saved on the bottom of the stack */
prev_esp = (u32 *)(end_stack - THREAD_SIZE);
stack = (unsigned long *)*prev_esp;
if (!stack)
stack_type_str(info.type, &begin_str, &end_str);
if (begin_str && ops->stack(data, begin_str) < 0)
break;
if (ops->stack(data, "IRQ") < 0)
bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
if (end_str && ops->stack(data, end_str) < 0)
break;
stack = info.next_sp;
touch_nmi_watchdog();
}
}

173
arch/x86/kernel/dumpstack_64.c
View File

@ -28,76 +28,109 @@ static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
[DEBUG_STACK - 1] = DEBUG_STKSZ
};
static unsigned long *in_exception_stack(unsigned long stack, unsigned *usedp,
char **idp)
void stack_type_str(enum stack_type type, const char **begin, const char **end)
{
unsigned long begin, end;
BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
switch (type) {
case STACK_TYPE_IRQ:
*begin = "IRQ";
*end = "EOI";
break;
case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
*begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
*end = "EOE";
break;
default:
*begin = NULL;
*end = NULL;
}
}
static bool in_exception_stack(unsigned long *stack, struct stack_info *info,
unsigned long *visit_mask)
{
unsigned long *begin, *end;
struct pt_regs *regs;
unsigned k;
BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
for (k = 0; k < N_EXCEPTION_STACKS; k++) {
end = raw_cpu_ptr(&orig_ist)->ist[k];
begin = end - exception_stack_sizes[k];
end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
begin = end - (exception_stack_sizes[k] / sizeof(long));
regs = (struct pt_regs *)end - 1;
if (stack < begin || stack >= end)
continue;
/*
* Make sure we only iterate through an exception stack once.
* If it comes up for the second time then there's something
* wrong going on - just break and return NULL:
* Make sure we don't iterate through an exception stack more
* than once. If it comes up a second time then there's
* something wrong going on - just break out and report an
* unknown stack type.
*/
if (*usedp & (1U << k))
if (*visit_mask & (1U << k))
break;
*usedp |= 1U << k;
*visit_mask |= 1U << k;
*idp = exception_stack_names[k];
return (unsigned long *)end;
info->type = STACK_TYPE_EXCEPTION + k;
info->begin = begin;
info->end = end;
info->next_sp = (unsigned long *)regs->sp;
return true;
}
return NULL;
return false;
}
static inline int
in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
unsigned long *irq_stack_end)
static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
return (stack >= irq_stack && stack < irq_stack_end);
unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
if (stack < begin || stack >= end)
return false;
info->type = STACK_TYPE_IRQ;
info->begin = begin;
info->end = end;
/*
* The next stack pointer is the first thing pushed by the entry code
* after switching to the irq stack.
*/
info->next_sp = (unsigned long *)*(end - 1);
return true;
}
enum stack_type {
STACK_IS_UNKNOWN,
STACK_IS_NORMAL,
STACK_IS_EXCEPTION,
STACK_IS_IRQ,
};
static enum stack_type
analyze_stack(struct task_struct *task, unsigned long *stack,
unsigned long **stack_end, unsigned long *irq_stack,
unsigned *used, char **id)
int get_stack_info(unsigned long *stack, struct task_struct *task,
struct stack_info *info, unsigned long *visit_mask)
{
unsigned long addr;
if (!stack)
goto unknown;
addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
if ((unsigned long)task_stack_page(task) == addr)
return STACK_IS_NORMAL;
task = task ? : current;
*stack_end = in_exception_stack((unsigned long)stack, used, id);
if (*stack_end)
return STACK_IS_EXCEPTION;
if (in_task_stack(stack, task, info))
return 0;
if (!irq_stack)
return STACK_IS_NORMAL;
if (task != current)
goto unknown;
*stack_end = irq_stack;
irq_stack -= (IRQ_STACK_SIZE / sizeof(long));
if (in_exception_stack(stack, info, visit_mask))
return 0;
if (in_irq_stack(stack, irq_stack, *stack_end))
return STACK_IS_IRQ;
if (in_irq_stack(stack, info))
return 0;
return STACK_IS_UNKNOWN;
return 0;
unknown:
info->type = STACK_TYPE_UNKNOWN;
return -EINVAL;
}
/*
@ -111,8 +144,8 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
unsigned long *irq_stack = (unsigned long *)this_cpu_read(irq_stack_ptr);
unsigned used = 0;
unsigned long visit_mask = 0;
struct stack_info info;
int graph = 0;
int done = 0;
@ -126,57 +159,37 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* exceptions
*/
while (!done) {
unsigned long *stack_end;
enum stack_type stype;
char *id;
const char *begin_str, *end_str;
stype = analyze_stack(task, stack, &stack_end, irq_stack, &used,
&id);
get_stack_info(stack, task, &info, &visit_mask);
/* Default finish unless specified to continue */
done = 1;
switch (stype) {
switch (info.type) {
/* Break out early if we are on the thread stack */
case STACK_IS_NORMAL:
case STACK_TYPE_TASK:
break;
case STACK_IS_EXCEPTION:
case STACK_TYPE_IRQ:
case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
if (ops->stack(data, id) < 0)
stack_type_str(info.type, &begin_str, &end_str);
if (ops->stack(data, begin_str) < 0)
break;
bp = ops->walk_stack(task, stack, bp, ops,
data, stack_end, &graph);
ops->stack(data, "EOE");
/*
* We link to the next stack via the
* second-to-last pointer (index -2 to end) in the
* exception stack:
*/
stack = (unsigned long *) stack_end[-2];
data, &info, &graph);
ops->stack(data, end_str);
stack = info.next_sp;
done = 0;
break;
case STACK_IS_IRQ:
if (ops->stack(data, "IRQ") < 0)
break;
bp = ops->walk_stack(task, stack, bp,
ops, data, stack_end, &graph);
/*
* We link to the next stack (which would be
* the process stack normally) the last
* pointer (index -1 to end) in the IRQ stack:
*/
stack = (unsigned long *) (stack_end[-1]);
irq_stack = NULL;
ops->stack(data, "EOI");
done = 0;
break;
case STACK_IS_UNKNOWN:
default:
ops->stack(data, "UNK");
break;
}
@ -185,7 +198,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
/*
* This handles the process stack:
*/
bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
}
EXPORT_SYMBOL(dump_trace);

2
arch/x86/kernel/stacktrace.c
View File

@ -9,7 +9,7 @@
#include <linux/uaccess.h>
#include <asm/stacktrace.h>
static int save_stack_stack(void *data, char *name)
static int save_stack_stack(void *data, const char *name)
{
return 0;
}

2
arch/x86/oprofile/backtrace.c
View File

@ -17,7 +17,7 @@
#include <asm/ptrace.h>
#include <asm/stacktrace.h>
static int backtrace_stack(void *data, char *name)
static int backtrace_stack(void *data, const char *name)
{
/* Yes, we want all stacks */
return 0;