arch/x86/kernel/dumpstack.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   4  */
   5 #include <linux/kallsyms.h>
   6 #include <linux/kprobes.h>
   7 #include <linux/uaccess.h>
   8 #include <linux/utsname.h>
   9 #include <linux/hardirq.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/module.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/ftrace.h>
  14 #include <linux/kexec.h>
  15 #include <linux/bug.h>
  16 #include <linux/nmi.h>
  17 #include <linux/sysfs.h>
  18
  19 #include <asm/stacktrace.h>
  20
  21
  22 int panic_on_unrecovered_nmi;
  23 int panic_on_io_nmi;
  24 unsigned int code_bytes = 64;
  25 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
  26 static int die_counter;
  27
  28 void printk_address(unsigned long address, int reliable)
  29 {
  30         pr_cont(" [<%p>] %s%pB\n",
  31                 (void *)address, reliable ? "" : "? ", (void *)address);
  32 }
  33
  34 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  35 static void
  36 print_ftrace_graph_addr(unsigned long addr, void *data,
  37                         const struct stacktrace_ops *ops,
  38                         struct thread_info *tinfo, int *graph)
  39 {
  40         struct task_struct *task;
  41         unsigned long ret_addr;
  42         int index;
  43
  44         if (addr != (unsigned long)return_to_handler)
  45                 return;
  46
  47         task = tinfo->task;
  48         index = task->curr_ret_stack;
  49
  50         if (!task->ret_stack || index < *graph)
  51                 return;
  52
  53         index -= *graph;
  54         ret_addr = task->ret_stack[index].ret;
  55
  56         ops->address(data, ret_addr, 1);
  57
  58         (*graph)++;
  59 }
  60 #else
  61 static inline void
  62 print_ftrace_graph_addr(unsigned long addr, void *data,
  63                         const struct stacktrace_ops *ops,
  64                         struct thread_info *tinfo, int *graph)
  65 { }
  66 #endif
  67
  68 /*
  69  * x86-64 can have up to three kernel stacks:
  70  * process stack
  71  * interrupt stack
  72  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  73  */
  74
  75 static inline int valid_stack_ptr(struct thread_info *tinfo,
  76                         void *p, unsigned int size, void *end)
  77 {
  78         void *t = tinfo;
  79         if (end) {
  80                 if (p < end && p >= (end-THREAD_SIZE))
  81                         return 1;
  82                 else
  83                         return 0;
  84         }
  85         return p > t && p < t + THREAD_SIZE - size;
  86 }
  87
  88 unsigned long
  89 print_context_stack(struct thread_info *tinfo,
  90                 unsigned long *stack, unsigned long bp,
  91                 const struct stacktrace_ops *ops, void *data,
  92                 unsigned long *end, int *graph)
  93 {
  94         struct stack_frame *frame = (struct stack_frame *)bp;
  95
  96         while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
  97                 unsigned long addr;
  98
  99                 addr = *stack;
 100                 if (__kernel_text_address(addr)) {
 101                         if ((unsigned long) stack == bp + sizeof(long)) {
 102                                 ops->address(data, addr, 1);
 103                                 frame = frame->next_frame;
 104                                 bp = (unsigned long) frame;
 105                         } else {
 106                                 ops->address(data, addr, 0);
 107                         }
 108                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 109                 }
 110                 stack++;
 111         }
 112         return bp;
 113 }
 114 EXPORT_SYMBOL_GPL(print_context_stack);
 115
 116 unsigned long
 117 print_context_stack_bp(struct thread_info *tinfo,
 118                        unsigned long *stack, unsigned long bp,
 119                        const struct stacktrace_ops *ops, void *data,
 120                        unsigned long *end, int *graph)
 121 {
 122         struct stack_frame *frame = (struct stack_frame *)bp;
 123         unsigned long *ret_addr = &frame->return_address;
 124
 125         while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
 126                 unsigned long addr = *ret_addr;
 127
 128                 if (!__kernel_text_address(addr))
 129                         break;
 130
 131                 ops->address(data, addr, 1);
 132                 frame = frame->next_frame;
 133                 ret_addr = &frame->return_address;
 134                 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 135         }
 136
 137         return (unsigned long)frame;
 138 }
 139 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 140
 141 static int print_trace_stack(void *data, char *name)
 142 {
 143         printk("%s <%s> ", (char *)data, name);
 144         return 0;
 145 }
 146
 147 /*
 148  * Print one address/symbol entries per line.
 149  */
 150 static void print_trace_address(void *data, unsigned long addr, int reliable)
 151 {
 152         touch_nmi_watchdog();
 153         printk(data);
 154         printk_address(addr, reliable);
 155 }
 156
 157 static const struct stacktrace_ops print_trace_ops = {
 158         .stack                  = print_trace_stack,
 159         .address                = print_trace_address,
 160         .walk_stack             = print_context_stack,
 161 };
 162
 163 void
 164 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 165                 unsigned long *stack, unsigned long bp, char *log_lvl)
 166 {
 167         printk("%sCall Trace:\n", log_lvl);
 168         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 169 }
 170
 171 void show_trace(struct task_struct *task, struct pt_regs *regs,
 172                 unsigned long *stack, unsigned long bp)
 173 {
 174         show_trace_log_lvl(task, regs, stack, bp, "");
 175 }
 176
 177 void show_stack(struct task_struct *task, unsigned long *sp)
 178 {
 179         unsigned long bp = 0;
 180         unsigned long stack;
 181
 182         /*
 183          * Stack frames below this one aren't interesting.  Don't show them
 184          * if we're printing for %current.
 185          */
 186         if (!sp && (!task || task == current)) {
 187                 sp = &stack;
 188                 bp = stack_frame(current, NULL);
 189         }
 190
 191         show_stack_log_lvl(task, NULL, sp, bp, "");
 192 }
 193
 194 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 195 static int die_owner = -1;
 196 static unsigned int die_nest_count;
 197
 198 unsigned __kprobes long oops_begin(void)
 199 {
 200         int cpu;
 201         unsigned long flags;
 202
 203         oops_enter();
 204
 205         /* racy, but better than risking deadlock. */
 206         raw_local_irq_save(flags);
 207         cpu = smp_processor_id();
 208         if (!arch_spin_trylock(&die_lock)) {
 209                 if (cpu == die_owner)
 210                         /* nested oops. should stop eventually */;
 211                 else
 212                         arch_spin_lock(&die_lock);
 213         }
 214         die_nest_count++;
 215         die_owner = cpu;
 216         console_verbose();
 217         bust_spinlocks(1);
 218         return flags;
 219 }
 220 EXPORT_SYMBOL_GPL(oops_begin);
 221
 222 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 223 {
 224         if (regs && kexec_should_crash(current))
 225                 crash_kexec(regs);
 226
 227         bust_spinlocks(0);
 228         die_owner = -1;
 229         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 230         die_nest_count--;
 231         if (!die_nest_count)
 232                 /* Nest count reaches zero, release the lock. */
 233                 arch_spin_unlock(&die_lock);
 234         raw_local_irq_restore(flags);
 235         oops_exit();
 236
 237         if (!signr)
 238                 return;
 239         if (in_interrupt())
 240                 panic("Fatal exception in interrupt");
 241         if (panic_on_oops)
 242                 panic("Fatal exception");
 243         do_exit(signr);
 244 }
 245
 246 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 247 {
 248 #ifdef CONFIG_X86_32
 249         unsigned short ss;
 250         unsigned long sp;
 251 #endif
 252         printk(KERN_DEFAULT
 253                "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 254 #ifdef CONFIG_PREEMPT
 255         printk("PREEMPT ");
 256 #endif
 257 #ifdef CONFIG_SMP
 258         printk("SMP ");
 259 #endif
 260 #ifdef CONFIG_DEBUG_PAGEALLOC
 261         printk("DEBUG_PAGEALLOC");
 262 #endif
 263         printk("\n");
 264         if (notify_die(DIE_OOPS, str, regs, err,
 265                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 266                 return 1;
 267
 268         print_modules();
 269         show_regs(regs);
 270 #ifdef CONFIG_X86_32
 271         if (user_mode_vm(regs)) {
 272                 sp = regs->sp;
 273                 ss = regs->ss & 0xffff;
 274         } else {
 275                 sp = kernel_stack_pointer(regs);
 276                 savesegment(ss, ss);
 277         }
 278         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 279         print_symbol("%s", regs->ip);
 280         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 281 #else
 282         /* Executive summary in case the oops scrolled away */
 283         printk(KERN_ALERT "RIP ");
 284         printk_address(regs->ip, 1);
 285         printk(" RSP <%016lx>\n", regs->sp);
 286 #endif
 287         return 0;
 288 }
 289
 290 /*
 291  * This is gone through when something in the kernel has done something bad
 292  * and is about to be terminated:
 293  */
 294 void die(const char *str, struct pt_regs *regs, long err)
 295 {
 296         unsigned long flags = oops_begin();
 297         int sig = SIGSEGV;
 298
 299         if (!user_mode_vm(regs))
 300                 report_bug(regs->ip, regs);
 301
 302         if (__die(str, regs, err))
 303                 sig = 0;
 304         oops_end(flags, regs, sig);
 305 }
 306
 307 static int __init kstack_setup(char *s)
 308 {
 309         ssize_t ret;
 310         unsigned long val;
 311
 312         if (!s)
 313                 return -EINVAL;
 314
 315         ret = kstrtoul(s, 0, &val);
 316         if (ret)
 317                 return ret;
 318         kstack_depth_to_print = val;
 319         return 0;
 320 }
 321 early_param("kstack", kstack_setup);
 322
 323 static int __init code_bytes_setup(char *s)
 324 {
 325         ssize_t ret;
 326         unsigned long val;
 327
 328         if (!s)
 329                 return -EINVAL;
 330
 331         ret = kstrtoul(s, 0, &val);
 332         if (ret)
 333                 return ret;
 334
 335         code_bytes = val;
 336         if (code_bytes > 8192)
 337                 code_bytes = 8192;
 338
 339         return 1;
 340 }
 341 __setup("code_bytes=", code_bytes_setup);