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         printk(" [<%p>] %s%pB\n", (void *) address,
  31                         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         show_stack_log_lvl(task, NULL, sp, 0, "");
 180 }
 181
 182 /*
 183  * The architecture-independent dump_stack generator
 184  */
 185 void dump_stack(void)
 186 {
 187         unsigned long bp;
 188         unsigned long stack;
 189
 190         bp = stack_frame(current, NULL);
 191         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 192                 current->pid, current->comm, print_tainted(),
 193                 init_utsname()->release,
 194                 (int)strcspn(init_utsname()->version, " "),
 195                 init_utsname()->version);
 196         show_trace(NULL, NULL, &stack, bp);
 197 }
 198 EXPORT_SYMBOL(dump_stack);
 199
 200 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 201 static int die_owner = -1;
 202 static unsigned int die_nest_count;
 203
 204 unsigned __kprobes long oops_begin(void)
 205 {
 206         int cpu;
 207         unsigned long flags;
 208
 209         oops_enter();
 210
 211         /* racy, but better than risking deadlock. */
 212         raw_local_irq_save(flags);
 213         cpu = smp_processor_id();
 214         if (!arch_spin_trylock(&die_lock)) {
 215                 if (cpu == die_owner)
 216                         /* nested oops. should stop eventually */;
 217                 else
 218                         arch_spin_lock(&die_lock);
 219         }
 220         die_nest_count++;
 221         die_owner = cpu;
 222         console_verbose();
 223         bust_spinlocks(1);
 224         return flags;
 225 }
 226 EXPORT_SYMBOL_GPL(oops_begin);
 227
 228 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 229 {
 230         if (regs && kexec_should_crash(current))
 231                 crash_kexec(regs);
 232
 233         bust_spinlocks(0);
 234         die_owner = -1;
 235         add_taint(TAINT_DIE);
 236         die_nest_count--;
 237         if (!die_nest_count)
 238                 /* Nest count reaches zero, release the lock. */
 239                 arch_spin_unlock(&die_lock);
 240         raw_local_irq_restore(flags);
 241         oops_exit();
 242
 243         if (!signr)
 244                 return;
 245         if (in_interrupt())
 246                 panic("Fatal exception in interrupt");
 247         if (panic_on_oops)
 248                 panic("Fatal exception");
 249         do_exit(signr);
 250 }
 251
 252 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 253 {
 254 #ifdef CONFIG_X86_32
 255         unsigned short ss;
 256         unsigned long sp;
 257 #endif
 258         printk(KERN_DEFAULT
 259                "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 260 #ifdef CONFIG_PREEMPT
 261         printk("PREEMPT ");
 262 #endif
 263 #ifdef CONFIG_SMP
 264         printk("SMP ");
 265 #endif
 266 #ifdef CONFIG_DEBUG_PAGEALLOC
 267         printk("DEBUG_PAGEALLOC");
 268 #endif
 269         printk("\n");
 270         if (notify_die(DIE_OOPS, str, regs, err,
 271                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 272                 return 1;
 273
 274         show_regs(regs);
 275 #ifdef CONFIG_X86_32
 276         if (user_mode_vm(regs)) {
 277                 sp = regs->sp;
 278                 ss = regs->ss & 0xffff;
 279         } else {
 280                 sp = kernel_stack_pointer(regs);
 281                 savesegment(ss, ss);
 282         }
 283         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 284         print_symbol("%s", regs->ip);
 285         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 286 #else
 287         /* Executive summary in case the oops scrolled away */
 288         printk(KERN_ALERT "RIP ");
 289         printk_address(regs->ip, 1);
 290         printk(" RSP <%016lx>\n", regs->sp);
 291 #endif
 292         return 0;
 293 }
 294
 295 /*
 296  * This is gone through when something in the kernel has done something bad
 297  * and is about to be terminated:
 298  */
 299 void die(const char *str, struct pt_regs *regs, long err)
 300 {
 301         unsigned long flags = oops_begin();
 302         int sig = SIGSEGV;
 303
 304         if (!user_mode_vm(regs))
 305                 report_bug(regs->ip, regs);
 306
 307         if (__die(str, regs, err))
 308                 sig = 0;
 309         oops_end(flags, regs, sig);
 310 }
 311
 312 static int __init kstack_setup(char *s)
 313 {
 314         ssize_t ret;
 315         unsigned long val;
 316
 317         if (!s)
 318                 return -EINVAL;
 319
 320         ret = kstrtoul(s, 0, &val);
 321         if (ret)
 322                 return ret;
 323         kstack_depth_to_print = val;
 324         return 0;
 325 }
 326 early_param("kstack", kstack_setup);
 327
 328 static int __init code_bytes_setup(char *s)
 329 {
 330         ssize_t ret;
 331         unsigned long val;
 332
 333         if (!s)
 334                 return -EINVAL;
 335
 336         ret = kstrtoul(s, 0, &val);
 337         if (ret)
 338                 return ret;
 339
 340         code_bytes = val;
 341         if (code_bytes > 8192)
 342                 code_bytes = 8192;
 343
 344         return 1;
 345 }
 346 __setup("code_bytes=", code_bytes_setup);