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 #include "dumpstack.h"
  22
  23 int panic_on_unrecovered_nmi;
  24 int panic_on_io_nmi;
  25 unsigned int code_bytes = 64;
  26 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
  27 static int die_counter;
  28
  29 void printk_address(unsigned long address, int reliable)
  30 {
  31         printk(" [<%p>] %s%pS\n", (void *) address,
  32                         reliable ? "" : "? ", (void *) address);
  33 }
  34
  35 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  36 static void
  37 print_ftrace_graph_addr(unsigned long addr, void *data,
  38                         const struct stacktrace_ops *ops,
  39                         struct thread_info *tinfo, int *graph)
  40 {
  41         struct task_struct *task = tinfo->task;
  42         unsigned long ret_addr;
  43         int index = task->curr_ret_stack;
  44
  45         if (addr != (unsigned long)return_to_handler)
  46                 return;
  47
  48         if (!task->ret_stack || index < *graph)
  49                 return;
  50
  51         index -= *graph;
  52         ret_addr = task->ret_stack[index].ret;
  53
  54         ops->address(data, ret_addr, 1);
  55
  56         (*graph)++;
  57 }
  58 #else
  59 static inline void
  60 print_ftrace_graph_addr(unsigned long addr, void *data,
  61                         const struct stacktrace_ops *ops,
  62                         struct thread_info *tinfo, int *graph)
  63 { }
  64 #endif
  65
  66 /*
  67  * x86-64 can have up to three kernel stacks:
  68  * process stack
  69  * interrupt stack
  70  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  71  */
  72
  73 static inline int valid_stack_ptr(struct thread_info *tinfo,
  74                         void *p, unsigned int size, void *end)
  75 {
  76         void *t = tinfo;
  77         if (end) {
  78                 if (p < end && p >= (end-THREAD_SIZE))
  79                         return 1;
  80                 else
  81                         return 0;
  82         }
  83         return p > t && p < t + THREAD_SIZE - size;
  84 }
  85
  86 unsigned long
  87 print_context_stack(struct thread_info *tinfo,
  88                 unsigned long *stack, unsigned long bp,
  89                 const struct stacktrace_ops *ops, void *data,
  90                 unsigned long *end, int *graph)
  91 {
  92         struct stack_frame *frame = (struct stack_frame *)bp;
  93
  94         while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
  95                 unsigned long addr;
  96
  97                 addr = *stack;
  98                 if (__kernel_text_address(addr)) {
  99                         if ((unsigned long) stack == bp + sizeof(long)) {
 100                                 ops->address(data, addr, 1);
 101                                 frame = frame->next_frame;
 102                                 bp = (unsigned long) frame;
 103                         } else {
 104                                 ops->address(data, addr, 0);
 105                         }
 106                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 107                 }
 108                 stack++;
 109         }
 110         return bp;
 111 }
 112 EXPORT_SYMBOL_GPL(print_context_stack);
 113
 114 unsigned long
 115 print_context_stack_bp(struct thread_info *tinfo,
 116                        unsigned long *stack, unsigned long bp,
 117                        const struct stacktrace_ops *ops, void *data,
 118                        unsigned long *end, int *graph)
 119 {
 120         struct stack_frame *frame = (struct stack_frame *)bp;
 121         unsigned long *ret_addr = &frame->return_address;
 122
 123         while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
 124                 unsigned long addr = *ret_addr;
 125
 126                 if (!__kernel_text_address(addr))
 127                         break;
 128
 129                 ops->address(data, addr, 1);
 130                 frame = frame->next_frame;
 131                 ret_addr = &frame->return_address;
 132                 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 133         }
 134
 135         return (unsigned long)frame;
 136 }
 137 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 138
 139
 140 static void
 141 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
 142 {
 143         printk(data);
 144         print_symbol(msg, symbol);
 145         printk("\n");
 146 }
 147
 148 static void print_trace_warning(void *data, char *msg)
 149 {
 150         printk("%s%s\n", (char *)data, msg);
 151 }
 152
 153 static int print_trace_stack(void *data, char *name)
 154 {
 155         printk("%s <%s> ", (char *)data, name);
 156         return 0;
 157 }
 158
 159 /*
 160  * Print one address/symbol entries per line.
 161  */
 162 static void print_trace_address(void *data, unsigned long addr, int reliable)
 163 {
 164         touch_nmi_watchdog();
 165         printk(data);
 166         printk_address(addr, reliable);
 167 }
 168
 169 static const struct stacktrace_ops print_trace_ops = {
 170         .warning                = print_trace_warning,
 171         .warning_symbol         = print_trace_warning_symbol,
 172         .stack                  = print_trace_stack,
 173         .address                = print_trace_address,
 174         .walk_stack             = print_context_stack,
 175 };
 176
 177 void
 178 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 179                 unsigned long *stack, unsigned long bp, char *log_lvl)
 180 {
 181         printk("%sCall Trace:\n", log_lvl);
 182         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 183 }
 184
 185 void show_trace(struct task_struct *task, struct pt_regs *regs,
 186                 unsigned long *stack, unsigned long bp)
 187 {
 188         show_trace_log_lvl(task, regs, stack, bp, "");
 189 }
 190
 191 void show_stack(struct task_struct *task, unsigned long *sp)
 192 {
 193         show_stack_log_lvl(task, NULL, sp, 0, "");
 194 }
 195
 196 /*
 197  * The architecture-independent dump_stack generator
 198  */
 199 void dump_stack(void)
 200 {
 201         unsigned long bp = 0;
 202         unsigned long stack;
 203
 204 #ifdef CONFIG_FRAME_POINTER
 205         if (!bp)
 206                 get_bp(bp);
 207 #endif
 208
 209         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 210                 current->pid, current->comm, print_tainted(),
 211                 init_utsname()->release,
 212                 (int)strcspn(init_utsname()->version, " "),
 213                 init_utsname()->version);
 214         show_trace(NULL, NULL, &stack, bp);
 215 }
 216 EXPORT_SYMBOL(dump_stack);
 217
 218 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 219 static int die_owner = -1;
 220 static unsigned int die_nest_count;
 221
 222 unsigned __kprobes long oops_begin(void)
 223 {
 224         int cpu;
 225         unsigned long flags;
 226
 227         /* notify the hw-branch tracer so it may disable tracing and
 228            add the last trace to the trace buffer -
 229            the earlier this happens, the more useful the trace. */
 230         trace_hw_branch_oops();
 231
 232         oops_enter();
 233
 234         /* racy, but better than risking deadlock. */
 235         raw_local_irq_save(flags);
 236         cpu = smp_processor_id();
 237         if (!arch_spin_trylock(&die_lock)) {
 238                 if (cpu == die_owner)
 239                         /* nested oops. should stop eventually */;
 240                 else
 241                         arch_spin_lock(&die_lock);
 242         }
 243         die_nest_count++;
 244         die_owner = cpu;
 245         console_verbose();
 246         bust_spinlocks(1);
 247         return flags;
 248 }
 249
 250 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 251 {
 252         if (regs && kexec_should_crash(current))
 253                 crash_kexec(regs);
 254
 255         bust_spinlocks(0);
 256         die_owner = -1;
 257         add_taint(TAINT_DIE);
 258         die_nest_count--;
 259         if (!die_nest_count)
 260                 /* Nest count reaches zero, release the lock. */
 261                 arch_spin_unlock(&die_lock);
 262         raw_local_irq_restore(flags);
 263         oops_exit();
 264
 265         if (!signr)
 266                 return;
 267         if (in_interrupt())
 268                 panic("Fatal exception in interrupt");
 269         if (panic_on_oops)
 270                 panic("Fatal exception");
 271         do_exit(signr);
 272 }
 273
 274 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 275 {
 276 #ifdef CONFIG_X86_32
 277         unsigned short ss;
 278         unsigned long sp;
 279 #endif
 280         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 281 #ifdef CONFIG_PREEMPT
 282         printk("PREEMPT ");
 283 #endif
 284 #ifdef CONFIG_SMP
 285         printk("SMP ");
 286 #endif
 287 #ifdef CONFIG_DEBUG_PAGEALLOC
 288         printk("DEBUG_PAGEALLOC");
 289 #endif
 290         printk("\n");
 291         sysfs_printk_last_file();
 292         if (notify_die(DIE_OOPS, str, regs, err,
 293                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
 294                 return 1;
 295
 296         show_registers(regs);
 297 #ifdef CONFIG_X86_32
 298         if (user_mode_vm(regs)) {
 299                 sp = regs->sp;
 300                 ss = regs->ss & 0xffff;
 301         } else {
 302                 sp = kernel_stack_pointer(regs);
 303                 savesegment(ss, ss);
 304         }
 305         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 306         print_symbol("%s", regs->ip);
 307         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 308 #else
 309         /* Executive summary in case the oops scrolled away */
 310         printk(KERN_ALERT "RIP ");
 311         printk_address(regs->ip, 1);
 312         printk(" RSP <%016lx>\n", regs->sp);
 313 #endif
 314         return 0;
 315 }
 316
 317 /*
 318  * This is gone through when something in the kernel has done something bad
 319  * and is about to be terminated:
 320  */
 321 void die(const char *str, struct pt_regs *regs, long err)
 322 {
 323         unsigned long flags = oops_begin();
 324         int sig = SIGSEGV;
 325
 326         if (!user_mode_vm(regs))
 327                 report_bug(regs->ip, regs);
 328
 329         if (__die(str, regs, err))
 330                 sig = 0;
 331         oops_end(flags, regs, sig);
 332 }
 333
 334 void notrace __kprobes
 335 die_nmi(char *str, struct pt_regs *regs, int do_panic)
 336 {
 337         unsigned long flags;
 338
 339         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
 340                 return;
 341
 342         /*
 343          * We are in trouble anyway, lets at least try
 344          * to get a message out.
 345          */
 346         flags = oops_begin();
 347         printk(KERN_EMERG "%s", str);
 348         printk(" on CPU%d, ip %08lx, registers:\n",
 349                 smp_processor_id(), regs->ip);
 350         show_registers(regs);
 351         oops_end(flags, regs, 0);
 352         if (do_panic || panic_on_oops)
 353                 panic("Non maskable interrupt");
 354         nmi_exit();
 355         local_irq_enable();
 356         do_exit(SIGBUS);
 357 }
 358
 359 static int __init oops_setup(char *s)
 360 {
 361         if (!s)
 362                 return -EINVAL;
 363         if (!strcmp(s, "panic"))
 364                 panic_on_oops = 1;
 365         return 0;
 366 }
 367 early_param("oops", oops_setup);
 368
 369 static int __init kstack_setup(char *s)
 370 {
 371         if (!s)
 372                 return -EINVAL;
 373         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
 374         return 0;
 375 }
 376 early_param("kstack", kstack_setup);
 377
 378 static int __init code_bytes_setup(char *s)
 379 {
 380         code_bytes = simple_strtoul(s, NULL, 0);
 381         if (code_bytes > 8192)
 382                 code_bytes = 8192;
 383
 384         return 1;
 385 }
 386 __setup("code_bytes=", code_bytes_setup);