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
 113
 114 static void
 115 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
 116 {
 117         printk(data);
 118         print_symbol(msg, symbol);
 119         printk("\n");
 120 }
 121
 122 static void print_trace_warning(void *data, char *msg)
 123 {
 124         printk("%s%s\n", (char *)data, msg);
 125 }
 126
 127 static int print_trace_stack(void *data, char *name)
 128 {
 129         printk("%s <%s> ", (char *)data, name);
 130         return 0;
 131 }
 132
 133 /*
 134  * Print one address/symbol entries per line.
 135  */
 136 static void print_trace_address(void *data, unsigned long addr, int reliable)
 137 {
 138         touch_nmi_watchdog();
 139         printk(data);
 140         printk_address(addr, reliable);
 141 }
 142
 143 static const struct stacktrace_ops print_trace_ops = {
 144         .warning                = print_trace_warning,
 145         .warning_symbol         = print_trace_warning_symbol,
 146         .stack                  = print_trace_stack,
 147         .address                = print_trace_address,
 148         .walk_stack             = print_context_stack,
 149 };
 150
 151 void
 152 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 153                 unsigned long *stack, unsigned long bp, char *log_lvl)
 154 {
 155         printk("%sCall Trace:\n", log_lvl);
 156         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 157 }
 158
 159 void show_trace(struct task_struct *task, struct pt_regs *regs,
 160                 unsigned long *stack, unsigned long bp)
 161 {
 162         show_trace_log_lvl(task, regs, stack, bp, "");
 163 }
 164
 165 void show_stack(struct task_struct *task, unsigned long *sp)
 166 {
 167         show_stack_log_lvl(task, NULL, sp, 0, "");
 168 }
 169
 170 /*
 171  * The architecture-independent dump_stack generator
 172  */
 173 void dump_stack(void)
 174 {
 175         unsigned long bp = 0;
 176         unsigned long stack;
 177
 178 #ifdef CONFIG_FRAME_POINTER
 179         if (!bp)
 180                 get_bp(bp);
 181 #endif
 182
 183         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 184                 current->pid, current->comm, print_tainted(),
 185                 init_utsname()->release,
 186                 (int)strcspn(init_utsname()->version, " "),
 187                 init_utsname()->version);
 188         show_trace(NULL, NULL, &stack, bp);
 189 }
 190 EXPORT_SYMBOL(dump_stack);
 191
 192 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 193 static int die_owner = -1;
 194 static unsigned int die_nest_count;
 195
 196 unsigned __kprobes long oops_begin(void)
 197 {
 198         int cpu;
 199         unsigned long flags;
 200
 201         /* notify the hw-branch tracer so it may disable tracing and
 202            add the last trace to the trace buffer -
 203            the earlier this happens, the more useful the trace. */
 204         trace_hw_branch_oops();
 205
 206         oops_enter();
 207
 208         /* racy, but better than risking deadlock. */
 209         raw_local_irq_save(flags);
 210         cpu = smp_processor_id();
 211         if (!arch_spin_trylock(&die_lock)) {
 212                 if (cpu == die_owner)
 213                         /* nested oops. should stop eventually */;
 214                 else
 215                         arch_spin_lock(&die_lock);
 216         }
 217         die_nest_count++;
 218         die_owner = cpu;
 219         console_verbose();
 220         bust_spinlocks(1);
 221         return flags;
 222 }
 223
 224 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 225 {
 226         if (regs && kexec_should_crash(current))
 227                 crash_kexec(regs);
 228
 229         bust_spinlocks(0);
 230         die_owner = -1;
 231         add_taint(TAINT_DIE);
 232         die_nest_count--;
 233         if (!die_nest_count)
 234                 /* Nest count reaches zero, release the lock. */
 235                 arch_spin_unlock(&die_lock);
 236         raw_local_irq_restore(flags);
 237         oops_exit();
 238
 239         if (!signr)
 240                 return;
 241         if (in_interrupt())
 242                 panic("Fatal exception in interrupt");
 243         if (panic_on_oops)
 244                 panic("Fatal exception");
 245         do_exit(signr);
 246 }
 247
 248 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 249 {
 250 #ifdef CONFIG_X86_32
 251         unsigned short ss;
 252         unsigned long sp;
 253 #endif
 254         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 255 #ifdef CONFIG_PREEMPT
 256         printk("PREEMPT ");
 257 #endif
 258 #ifdef CONFIG_SMP
 259         printk("SMP ");
 260 #endif
 261 #ifdef CONFIG_DEBUG_PAGEALLOC
 262         printk("DEBUG_PAGEALLOC");
 263 #endif
 264         printk("\n");
 265         sysfs_printk_last_file();
 266         if (notify_die(DIE_OOPS, str, regs, err,
 267                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
 268                 return 1;
 269
 270         show_registers(regs);
 271 #ifdef CONFIG_X86_32
 272         if (user_mode_vm(regs)) {
 273                 sp = regs->sp;
 274                 ss = regs->ss & 0xffff;
 275         } else {
 276                 sp = kernel_stack_pointer(regs);
 277                 savesegment(ss, ss);
 278         }
 279         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 280         print_symbol("%s", regs->ip);
 281         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 282 #else
 283         /* Executive summary in case the oops scrolled away */
 284         printk(KERN_ALERT "RIP ");
 285         printk_address(regs->ip, 1);
 286         printk(" RSP <%016lx>\n", regs->sp);
 287 #endif
 288         return 0;
 289 }
 290
 291 /*
 292  * This is gone through when something in the kernel has done something bad
 293  * and is about to be terminated:
 294  */
 295 void die(const char *str, struct pt_regs *regs, long err)
 296 {
 297         unsigned long flags = oops_begin();
 298         int sig = SIGSEGV;
 299
 300         if (!user_mode_vm(regs))
 301                 report_bug(regs->ip, regs);
 302
 303         if (__die(str, regs, err))
 304                 sig = 0;
 305         oops_end(flags, regs, sig);
 306 }
 307
 308 void notrace __kprobes
 309 die_nmi(char *str, struct pt_regs *regs, int do_panic)
 310 {
 311         unsigned long flags;
 312
 313         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
 314                 return;
 315
 316         /*
 317          * We are in trouble anyway, lets at least try
 318          * to get a message out.
 319          */
 320         flags = oops_begin();
 321         printk(KERN_EMERG "%s", str);
 322         printk(" on CPU%d, ip %08lx, registers:\n",
 323                 smp_processor_id(), regs->ip);
 324         show_registers(regs);
 325         oops_end(flags, regs, 0);
 326         if (do_panic || panic_on_oops)
 327                 panic("Non maskable interrupt");
 328         nmi_exit();
 329         local_irq_enable();
 330         do_exit(SIGBUS);
 331 }
 332
 333 static int __init oops_setup(char *s)
 334 {
 335         if (!s)
 336                 return -EINVAL;
 337         if (!strcmp(s, "panic"))
 338                 panic_on_oops = 1;
 339         return 0;
 340 }
 341 early_param("oops", oops_setup);
 342
 343 static int __init kstack_setup(char *s)
 344 {
 345         if (!s)
 346                 return -EINVAL;
 347         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
 348         return 0;
 349 }
 350 early_param("kstack", kstack_setup);
 351
 352 static int __init code_bytes_setup(char *s)
 353 {
 354         code_bytes = simple_strtoul(s, NULL, 0);
 355         if (code_bytes > 8192)
 356                 code_bytes = 8192;
 357
 358         return 1;
 359 }
 360 __setup("code_bytes=", code_bytes_setup);