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 task_struct *task, int *graph)
  46 {
  47         unsigned long ret_addr;
  48         int index;
  49
  50         if (addr != (unsigned long)return_to_handler)
  51                 return;
  52
  53         index = task->curr_ret_stack;
  54
  55         if (!task->ret_stack || index < *graph)
  56                 return;
  57
  58         index -= *graph;
  59         ret_addr = task->ret_stack[index].ret;
  60
  61         ops->address(data, ret_addr, 1);
  62
  63         (*graph)++;
  64 }
  65 #else
  66 static inline void
  67 print_ftrace_graph_addr(unsigned long addr, void *data,
  68                         const struct stacktrace_ops *ops,
  69                         struct task_struct *task, int *graph)
  70 { }
  71 #endif
  72
  73 /*
  74  * x86-64 can have up to three kernel stacks:
  75  * process stack
  76  * interrupt stack
  77  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  78  */
  79
  80 static inline int valid_stack_ptr(struct task_struct *task,
  81                         void *p, unsigned int size, void *end)
  82 {
  83         void *t = task_stack_page(task);
  84         if (end) {
  85                 if (p < end && p >= (end-THREAD_SIZE))
  86                         return 1;
  87                 else
  88                         return 0;
  89         }
  90         return p > t && p < t + THREAD_SIZE - size;
  91 }
  92
  93 unsigned long
  94 print_context_stack(struct task_struct *task,
  95                 unsigned long *stack, unsigned long bp,
  96                 const struct stacktrace_ops *ops, void *data,
  97                 unsigned long *end, int *graph)
  98 {
  99         struct stack_frame *frame = (struct stack_frame *)bp;
 100
 101         while (valid_stack_ptr(task, stack, sizeof(*stack), end)) {
 102                 unsigned long addr;
 103
 104                 addr = *stack;
 105                 if (__kernel_text_address(addr)) {
 106                         if ((unsigned long) stack == bp + sizeof(long)) {
 107                                 ops->address(data, addr, 1);
 108                                 frame = frame->next_frame;
 109                                 bp = (unsigned long) frame;
 110                         } else {
 111                                 ops->address(data, addr, 0);
 112                         }
 113                         print_ftrace_graph_addr(addr, data, ops, task, graph);
 114                 }
 115                 stack++;
 116         }
 117         return bp;
 118 }
 119 EXPORT_SYMBOL_GPL(print_context_stack);
 120
 121 unsigned long
 122 print_context_stack_bp(struct task_struct *task,
 123                        unsigned long *stack, unsigned long bp,
 124                        const struct stacktrace_ops *ops, void *data,
 125                        unsigned long *end, int *graph)
 126 {
 127         struct stack_frame *frame = (struct stack_frame *)bp;
 128         unsigned long *ret_addr = &frame->return_address;
 129
 130         while (valid_stack_ptr(task, ret_addr, sizeof(*ret_addr), end)) {
 131                 unsigned long addr = *ret_addr;
 132
 133                 if (!__kernel_text_address(addr))
 134                         break;
 135
 136                 if (ops->address(data, addr, 1))
 137                         break;
 138                 frame = frame->next_frame;
 139                 ret_addr = &frame->return_address;
 140                 print_ftrace_graph_addr(addr, data, ops, task, graph);
 141         }
 142
 143         return (unsigned long)frame;
 144 }
 145 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 146
 147 static int print_trace_stack(void *data, char *name)
 148 {
 149         printk("%s <%s> ", (char *)data, name);
 150         return 0;
 151 }
 152
 153 /*
 154  * Print one address/symbol entries per line.
 155  */
 156 static int print_trace_address(void *data, unsigned long addr, int reliable)
 157 {
 158         touch_nmi_watchdog();
 159         printk_stack_address(addr, reliable, data);
 160         return 0;
 161 }
 162
 163 static const struct stacktrace_ops print_trace_ops = {
 164         .stack                  = print_trace_stack,
 165         .address                = print_trace_address,
 166         .walk_stack             = print_context_stack,
 167 };
 168
 169 void
 170 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 171                 unsigned long *stack, unsigned long bp, char *log_lvl)
 172 {
 173         printk("%sCall Trace:\n", log_lvl);
 174         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 175 }
 176
 177 void show_trace(struct task_struct *task, struct pt_regs *regs,
 178                 unsigned long *stack, unsigned long bp)
 179 {
 180         show_trace_log_lvl(task, regs, stack, bp, "");
 181 }
 182
 183 void show_stack(struct task_struct *task, unsigned long *sp)
 184 {
 185         unsigned long bp = 0;
 186         unsigned long stack;
 187
 188         /*
 189          * Stack frames below this one aren't interesting.  Don't show them
 190          * if we're printing for %current.
 191          */
 192         if (!sp && (!task || task == current)) {
 193                 sp = &stack;
 194                 bp = stack_frame(current, NULL);
 195         }
 196
 197         show_stack_log_lvl(task, NULL, sp, bp, "");
 198 }
 199
 200 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 201 static int die_owner = -1;
 202 static unsigned int die_nest_count;
 203
 204 unsigned long oops_begin(void)
 205 {
 206         int cpu;
 207         unsigned long flags;
 208
 209         oops_enter();
 210
 211         /* racy, but better than risking deadlock. */
 212         raw_local_irq_save(flags);
 213         cpu = smp_processor_id();
 214         if (!arch_spin_trylock(&die_lock)) {
 215                 if (cpu == die_owner)
 216                         /* nested oops. should stop eventually */;
 217                 else
 218                         arch_spin_lock(&die_lock);
 219         }
 220         die_nest_count++;
 221         die_owner = cpu;
 222         console_verbose();
 223         bust_spinlocks(1);
 224         return flags;
 225 }
 226 EXPORT_SYMBOL_GPL(oops_begin);
 227 NOKPROBE_SYMBOL(oops_begin);
 228
 229 void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 230 {
 231         if (regs && kexec_should_crash(current))
 232                 crash_kexec(regs);
 233
 234         bust_spinlocks(0);
 235         die_owner = -1;
 236         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 237         die_nest_count--;
 238         if (!die_nest_count)
 239                 /* Nest count reaches zero, release the lock. */
 240                 arch_spin_unlock(&die_lock);
 241         raw_local_irq_restore(flags);
 242         oops_exit();
 243
 244         if (!signr)
 245                 return;
 246         if (in_interrupt())
 247                 panic("Fatal exception in interrupt");
 248         if (panic_on_oops)
 249                 panic("Fatal exception");
 250         do_exit(signr);
 251 }
 252 NOKPROBE_SYMBOL(oops_end);
 253
 254 int __die(const char *str, struct pt_regs *regs, long err)
 255 {
 256 #ifdef CONFIG_X86_32
 257         unsigned short ss;
 258         unsigned long sp;
 259 #endif
 260         printk(KERN_DEFAULT
 261                "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,
 262                IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",
 263                IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",
 264                debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",
 265                IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : "");
 266
 267         if (notify_die(DIE_OOPS, str, regs, err,
 268                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 269                 return 1;
 270
 271         print_modules();
 272         show_regs(regs);
 273 #ifdef CONFIG_X86_32
 274         if (user_mode(regs)) {
 275                 sp = regs->sp;
 276                 ss = regs->ss & 0xffff;
 277         } else {
 278                 sp = kernel_stack_pointer(regs);
 279                 savesegment(ss, ss);
 280         }
 281         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 282         print_symbol("%s", regs->ip);
 283         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 284 #else
 285         /* Executive summary in case the oops scrolled away */
 286         printk(KERN_ALERT "RIP ");
 287         printk_address(regs->ip);
 288         printk(" RSP <%016lx>\n", regs->sp);
 289 #endif
 290         return 0;
 291 }
 292 NOKPROBE_SYMBOL(__die);
 293
 294 /*
 295  * This is gone through when something in the kernel has done something bad
 296  * and is about to be terminated:
 297  */
 298 void die(const char *str, struct pt_regs *regs, long err)
 299 {
 300         unsigned long flags = oops_begin();
 301         int sig = SIGSEGV;
 302
 303         if (!user_mode(regs))
 304                 report_bug(regs->ip, regs);
 305
 306         if (__die(str, regs, err))
 307                 sig = 0;
 308         oops_end(flags, regs, sig);
 309 }
 310
 311 static int __init kstack_setup(char *s)
 312 {
 313         ssize_t ret;
 314         unsigned long val;
 315
 316         if (!s)
 317                 return -EINVAL;
 318
 319         ret = kstrtoul(s, 0, &val);
 320         if (ret)
 321                 return ret;
 322         kstack_depth_to_print = val;
 323         return 0;
 324 }
 325 early_param("kstack", kstack_setup);
 326
 327 static int __init code_bytes_setup(char *s)
 328 {
 329         ssize_t ret;
 330         unsigned long val;
 331
 332         if (!s)
 333                 return -EINVAL;
 334
 335         ret = kstrtoul(s, 0, &val);
 336         if (ret)
 337                 return ret;
 338
 339         code_bytes = val;
 340         if (code_bytes > 8192)
 341                 code_bytes = 8192;
 342
 343         return 1;
 344 }
 345 __setup("code_bytes=", code_bytes_setup);