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