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 static void printk_stack_address(unsigned long address, int reliable,
  29                 void *data)
  30 {
  31         printk("%s [<%p>] %s%pB\n",
  32                 (char *)data, (void *)address, reliable ? "" : "? ",
  33                 (void *)address);
  34 }
  35
  36 void printk_address(unsigned long address)
  37 {
  38         pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
  39 }
  40
  41 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  42 static void
  43 print_ftrace_graph_addr(unsigned long addr, void *data,
  44                         const struct stacktrace_ops *ops,
  45                         struct thread_info *tinfo, int *graph)
  46 {
  47         struct task_struct *task;
  48         unsigned long ret_addr;
  49         int index;
  50
  51         if (addr != (unsigned long)return_to_handler)
  52                 return;
  53
  54         task = tinfo->task;
  55         index = task->curr_ret_stack;
  56
  57         if (!task->ret_stack || index < *graph)
  58                 return;
  59
  60         index -= *graph;
  61         ret_addr = task->ret_stack[index].ret;
  62
  63         ops->address(data, ret_addr, 1);
  64
  65         (*graph)++;
  66 }
  67 #else
  68 static inline void
  69 print_ftrace_graph_addr(unsigned long addr, void *data,
  70                         const struct stacktrace_ops *ops,
  71                         struct thread_info *tinfo, int *graph)
  72 { }
  73 #endif
  74
  75 /*
  76  * x86-64 can have up to three kernel stacks:
  77  * process stack
  78  * interrupt stack
  79  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  80  */
  81
  82 static inline int valid_stack_ptr(struct thread_info *tinfo,
  83                         void *p, unsigned int size, void *end)
  84 {
  85         void *t = tinfo;
  86         if (end) {
  87                 if (p < end && p >= (end-THREAD_SIZE))
  88                         return 1;
  89                 else
  90                         return 0;
  91         }
  92         return p > t && p < t + THREAD_SIZE - size;
  93 }
  94
  95 unsigned long
  96 print_context_stack(struct thread_info *tinfo,
  97                 unsigned long *stack, unsigned long bp,
  98                 const struct stacktrace_ops *ops, void *data,
  99                 unsigned long *end, int *graph)
 100 {
 101         struct stack_frame *frame = (struct stack_frame *)bp;
 102
 103         while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
 104                 unsigned long addr;
 105
 106                 addr = *stack;
 107                 if (__kernel_text_address(addr)) {
 108                         if ((unsigned long) stack == bp + sizeof(long)) {
 109                                 ops->address(data, addr, 1);
 110                                 frame = frame->next_frame;
 111                                 bp = (unsigned long) frame;
 112                         } else {
 113                                 ops->address(data, addr, 0);
 114                         }
 115                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 116                 }
 117                 stack++;
 118         }
 119         return bp;
 120 }
 121 EXPORT_SYMBOL_GPL(print_context_stack);
 122
 123 unsigned long
 124 print_context_stack_bp(struct thread_info *tinfo,
 125                        unsigned long *stack, unsigned long bp,
 126                        const struct stacktrace_ops *ops, void *data,
 127                        unsigned long *end, int *graph)
 128 {
 129         struct stack_frame *frame = (struct stack_frame *)bp;
 130         unsigned long *ret_addr = &frame->return_address;
 131
 132         while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
 133                 unsigned long addr = *ret_addr;
 134
 135                 if (!__kernel_text_address(addr))
 136                         break;
 137
 138                 if (ops->address(data, addr, 1))
 139                         break;
 140                 frame = frame->next_frame;
 141                 ret_addr = &frame->return_address;
 142                 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 143         }
 144
 145         return (unsigned long)frame;
 146 }
 147 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 148
 149 static int print_trace_stack(void *data, char *name)
 150 {
 151         printk("%s <%s> ", (char *)data, name);
 152         return 0;
 153 }
 154
 155 /*
 156  * Print one address/symbol entries per line.
 157  */
 158 static int print_trace_address(void *data, unsigned long addr, int reliable)
 159 {
 160         touch_nmi_watchdog();
 161         printk_stack_address(addr, reliable, data);
 162         return 0;
 163 }
 164
 165 static const struct stacktrace_ops print_trace_ops = {
 166         .stack                  = print_trace_stack,
 167         .address                = print_trace_address,
 168         .walk_stack             = print_context_stack,
 169 };
 170
 171 void
 172 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 173                 unsigned long *stack, unsigned long bp, char *log_lvl)
 174 {
 175         printk("%sCall Trace:\n", log_lvl);
 176         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 177 }
 178
 179 void show_trace(struct task_struct *task, struct pt_regs *regs,
 180                 unsigned long *stack, unsigned long bp)
 181 {
 182         show_trace_log_lvl(task, regs, stack, bp, "");
 183 }
 184
 185 void show_stack(struct task_struct *task, unsigned long *sp)
 186 {
 187         unsigned long bp = 0;
 188         unsigned long stack;
 189
 190         /*
 191          * Stack frames below this one aren't interesting.  Don't show them
 192          * if we're printing for %current.
 193          */
 194         if (!sp && (!task || task == current)) {
 195                 sp = &stack;
 196                 bp = stack_frame(current, NULL);
 197         }
 198
 199         show_stack_log_lvl(task, NULL, sp, bp, "");
 200 }
 201
 202 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 203 static int die_owner = -1;
 204 static unsigned int die_nest_count;
 205
 206 unsigned long oops_begin(void)
 207 {
 208         int cpu;
 209         unsigned long flags;
 210
 211         oops_enter();
 212
 213         /* racy, but better than risking deadlock. */
 214         raw_local_irq_save(flags);
 215         cpu = smp_processor_id();
 216         if (!arch_spin_trylock(&die_lock)) {
 217                 if (cpu == die_owner)
 218                         /* nested oops. should stop eventually */;
 219                 else
 220                         arch_spin_lock(&die_lock);
 221         }
 222         die_nest_count++;
 223         die_owner = cpu;
 224         console_verbose();
 225         bust_spinlocks(1);
 226         return flags;
 227 }
 228 EXPORT_SYMBOL_GPL(oops_begin);
 229 NOKPROBE_SYMBOL(oops_begin);
 230
 231 void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 232 {
 233         if (regs && kexec_should_crash(current))
 234                 crash_kexec(regs);
 235
 236         bust_spinlocks(0);
 237         die_owner = -1;
 238         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 239         die_nest_count--;
 240         if (!die_nest_count)
 241                 /* Nest count reaches zero, release the lock. */
 242                 arch_spin_unlock(&die_lock);
 243         raw_local_irq_restore(flags);
 244         oops_exit();
 245
 246         if (!signr)
 247                 return;
 248         if (in_interrupt())
 249                 panic("Fatal exception in interrupt");
 250         if (panic_on_oops)
 251                 panic("Fatal exception");
 252         do_exit(signr);
 253 }
 254 NOKPROBE_SYMBOL(oops_end);
 255
 256 int __die(const char *str, struct pt_regs *regs, long err)
 257 {
 258 #ifdef CONFIG_X86_32
 259         unsigned short ss;
 260         unsigned long sp;
 261 #endif
 262         printk(KERN_DEFAULT
 263                "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
 264                IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
 265                IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
 266                debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
 267                IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "");
 268
 269         if (notify_die(DIE_OOPS, str, regs, err,
 270                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 271                 return 1;
 272
 273         print_modules();
 274         show_regs(regs);
 275 #ifdef CONFIG_X86_32
 276         if (user_mode(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);
 290         printk(" RSP <%016lx>\n", regs->sp);
 291 #endif
 292         return 0;
 293 }
 294 NOKPROBE_SYMBOL(__die);
 295
 296 /*
 297  * This is gone through when something in the kernel has done something bad
 298  * and is about to be terminated:
 299  */
 300 void die(const char *str, struct pt_regs *regs, long err)
 301 {
 302         unsigned long flags = oops_begin();
 303         int sig = SIGSEGV;
 304
 305         if (!user_mode(regs))
 306                 report_bug(regs->ip, regs);
 307
 308         if (__die(str, regs, err))
 309                 sig = 0;
 310         oops_end(flags, regs, sig);
 311 }
 312
 313 static int __init kstack_setup(char *s)
 314 {
 315         ssize_t ret;
 316         unsigned long val;
 317
 318         if (!s)
 319                 return -EINVAL;
 320
 321         ret = kstrtoul(s, 0, &val);
 322         if (ret)
 323                 return ret;
 324         kstack_depth_to_print = val;
 325         return 0;
 326 }
 327 early_param("kstack", kstack_setup);
 328
 329 static int __init code_bytes_setup(char *s)
 330 {
 331         ssize_t ret;
 332         unsigned long val;
 333
 334         if (!s)
 335                 return -EINVAL;
 336
 337         ret = kstrtoul(s, 0, &val);
 338         if (ret)
 339                 return ret;
 340
 341         code_bytes = val;
 342         if (code_bytes > 8192)
 343                 code_bytes = 8192;
 344
 345         return 1;
 346 }
 347 __setup("code_bytes=", code_bytes_setup);