Files
android_kernel_xiaomi_sm8450/arch/x86/kernel/dumpstack_32.c
Josh Poimboeuf 5fe599e02e x86/dumpstack: Add support for unwinding empty IRQ stacks
When an interrupt happens in entry code while running on a software IRQ
stack, and the IRQ stack was empty, regs->sp will contain the stack end
address (e.g., irq_stack_ptr).  If the regs are passed to dump_trace(),
get_stack_info() will report STACK_TYPE_UNKNOWN, causing dump_trace() to
return prematurely without trying to go to the next stack.

Update the bounds checking for software interrupt stacks so that the
ending address is now considered part of the stack.

This means that it's now possible for the 'walk_stack' callbacks --
print_context_stack() and print_context_stack_bp() -- to be called with
an empty stack.  But that's fine; they're already prepared to deal with
that due to their on_stack() checks.

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/5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-15 08:13:15 +02:00

223 lines
4.7 KiB
C

/*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
*/
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/kexec.h>
#include <linux/sysfs.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <asm/stacktrace.h>
void stack_type_str(enum stack_type type, const char **begin, const char **end)
{
switch (type) {
case STACK_TYPE_IRQ:
case STACK_TYPE_SOFTIRQ:
*begin = "IRQ";
*end = "EOI";
break;
default:
*begin = NULL;
*end = NULL;
}
}
static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
{
unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
/*
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
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 bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
{
unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack);
unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
/*
* This is a software stack, so 'end' can be a valid stack pointer.
* It just means the stack is empty.
*/
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;
task = task ? : current;
stack = stack ? : get_stack_pointer(task, regs);
bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
for (;;) {
const char *begin_str, *end_str;
struct stack_info info;
if (get_stack_info(stack, task, &info, &visit_mask))
break;
stack_type_str(info.type, &begin_str, &end_str);
if (begin_str && ops->stack(data, begin_str) < 0)
break;
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();
}
}
EXPORT_SYMBOL(dump_trace);
void
show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
unsigned long *sp, unsigned long bp, char *log_lvl)
{
unsigned long *stack;
int i;
sp = sp ? : get_stack_pointer(task, regs);
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
if (kstack_end(stack))
break;
if ((i % STACKSLOTS_PER_LINE) == 0) {
if (i != 0)
pr_cont("\n");
printk("%s %08lx", log_lvl, *stack++);
} else
pr_cont(" %08lx", *stack++);
touch_nmi_watchdog();
}
pr_cont("\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
}
void show_regs(struct pt_regs *regs)
{
int i;
show_regs_print_info(KERN_EMERG);
__show_regs(regs, !user_mode(regs));
/*
* When in-kernel, we also print out the stack and code at the
* time of the fault..
*/
if (!user_mode(regs)) {
unsigned int code_prologue = code_bytes * 43 / 64;
unsigned int code_len = code_bytes;
unsigned char c;
u8 *ip;
pr_emerg("Stack:\n");
show_stack_log_lvl(NULL, regs, NULL, 0, KERN_EMERG);
pr_emerg("Code:");
ip = (u8 *)regs->ip - code_prologue;
if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
/* try starting at IP */
ip = (u8 *)regs->ip;
code_len = code_len - code_prologue + 1;
}
for (i = 0; i < code_len; i++, ip++) {
if (ip < (u8 *)PAGE_OFFSET ||
probe_kernel_address(ip, c)) {
pr_cont(" Bad EIP value.");
break;
}
if (ip == (u8 *)regs->ip)
pr_cont(" <%02x>", c);
else
pr_cont(" %02x", c);
}
}
pr_cont("\n");
}
int is_valid_bugaddr(unsigned long ip)
{
unsigned short ud2;
if (ip < PAGE_OFFSET)
return 0;
if (probe_kernel_address((unsigned short *)ip, ud2))
return 0;
return ud2 == 0x0b0f;
}