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 };
 149
 150 void
 151 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 152                 unsigned long *stack, unsigned long bp, char *log_lvl)
 153 {
 154         printk("%sCall Trace:\n", log_lvl);
 155         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 156 }
 157
 158 void show_trace(struct task_struct *task, struct pt_regs *regs,
 159                 unsigned long *stack, unsigned long bp)
 160 {
 161         show_trace_log_lvl(task, regs, stack, bp, "");
 162 }
 163
 164 void show_stack(struct task_struct *task, unsigned long *sp)
 165 {
 166         show_stack_log_lvl(task, NULL, sp, 0, "");
 167 }
 168
 169 /*
 170  * The architecture-independent dump_stack generator
 171  */
 172 void dump_stack(void)
 173 {
 174         unsigned long bp = 0;
 175         unsigned long stack;
 176
 177 #ifdef CONFIG_FRAME_POINTER
 178         if (!bp)
 179                 get_bp(bp);
 180 #endif
 181
 182         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 183                 current->pid, current->comm, print_tainted(),
 184                 init_utsname()->release,
 185                 (int)strcspn(init_utsname()->version, " "),
 186                 init_utsname()->version);
 187         show_trace(NULL, NULL, &stack, bp);
 188 }
 189 EXPORT_SYMBOL(dump_stack);
 190
 191 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 192 static int die_owner = -1;
 193 static unsigned int die_nest_count;
 194
 195 unsigned __kprobes long oops_begin(void)
 196 {
 197         int cpu;
 198         unsigned long flags;
 199
 200         /* notify the hw-branch tracer so it may disable tracing and
 201            add the last trace to the trace buffer -
 202            the earlier this happens, the more useful the trace. */
 203         trace_hw_branch_oops();
 204
 205         oops_enter();
 206
 207         /* racy, but better than risking deadlock. */
 208         raw_local_irq_save(flags);
 209         cpu = smp_processor_id();
 210         if (!arch_spin_trylock(&die_lock)) {
 211                 if (cpu == die_owner)
 212                         /* nested oops. should stop eventually */;
 213                 else
 214                         arch_spin_lock(&die_lock);
 215         }
 216         die_nest_count++;
 217         die_owner = cpu;
 218         console_verbose();
 219         bust_spinlocks(1);
 220         return flags;
 221 }
 222
 223 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 224 {
 225         if (regs && kexec_should_crash(current))
 226                 crash_kexec(regs);
 227
 228         bust_spinlocks(0);
 229         die_owner = -1;
 230         add_taint(TAINT_DIE);
 231         die_nest_count--;
 232         if (!die_nest_count)
 233                 /* Nest count reaches zero, release the lock. */
 234                 arch_spin_unlock(&die_lock);
 235         raw_local_irq_restore(flags);
 236         oops_exit();
 237
 238         if (!signr)
 239                 return;
 240         if (in_interrupt())
 241                 panic("Fatal exception in interrupt");
 242         if (panic_on_oops)
 243                 panic("Fatal exception");
 244         do_exit(signr);
 245 }
 246
 247 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 248 {
 249 #ifdef CONFIG_X86_32
 250         unsigned short ss;
 251         unsigned long sp;
 252 #endif
 253         printk(KERN_EMERG "%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         sysfs_printk_last_file();
 265         if (notify_die(DIE_OOPS, str, regs, err,
 266                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
 267                 return 1;
 268
 269         show_registers(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 void notrace __kprobes
 308 die_nmi(char *str, struct pt_regs *regs, int do_panic)
 309 {
 310         unsigned long flags;
 311
 312         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
 313                 return;
 314
 315         /*
 316          * We are in trouble anyway, lets at least try
 317          * to get a message out.
 318          */
 319         flags = oops_begin();
 320         printk(KERN_EMERG "%s", str);
 321         printk(" on CPU%d, ip %08lx, registers:\n",
 322                 smp_processor_id(), regs->ip);
 323         show_registers(regs);
 324         oops_end(flags, regs, 0);
 325         if (do_panic || panic_on_oops)
 326                 panic("Non maskable interrupt");
 327         nmi_exit();
 328         local_irq_enable();
 329         do_exit(SIGBUS);
 330 }
 331
 332 static int __init oops_setup(char *s)
 333 {
 334         if (!s)
 335                 return -EINVAL;
 336         if (!strcmp(s, "panic"))
 337                 panic_on_oops = 1;
 338         return 0;
 339 }
 340 early_param("oops", oops_setup);
 341
 342 static int __init kstack_setup(char *s)
 343 {
 344         if (!s)
 345                 return -EINVAL;
 346         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
 347         return 0;
 348 }
 349 early_param("kstack", kstack_setup);
 350
 351 static int __init code_bytes_setup(char *s)
 352 {
 353         code_bytes = simple_strtoul(s, NULL, 0);
 354         if (code_bytes > 8192)
 355                 code_bytes = 8192;
 356
 357         return 1;
 358 }
 359 __setup("code_bytes=", code_bytes_setup);