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 {
  30         pr_cont(" [<%p>] %s%pB\n",
  31                 (void *)address, reliable ? "" : "? ", (void *)address);
  32 }
  33
  34 void printk_address(unsigned long address)
  35 {
  36         pr_cont(" [<%p>] %pS\n", (void *)address, (void *)address);
  37 }
  38
  39 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
  40 static void
  41 print_ftrace_graph_addr(unsigned long addr, void *data,
  42                         const struct stacktrace_ops *ops,
  43                         struct thread_info *tinfo, int *graph)
  44 {
  45         struct task_struct *task;
  46         unsigned long ret_addr;
  47         int index;
  48
  49         if (addr != (unsigned long)return_to_handler)
  50                 return;
  51
  52         task = tinfo->task;
  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 thread_info *tinfo, 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 thread_info *tinfo,
  81                         void *p, unsigned int size, void *end)
  82 {
  83         void *t = tinfo;
  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 thread_info *tinfo,
  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(tinfo, 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, tinfo, 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 thread_info *tinfo,
 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(tinfo, ret_addr, sizeof(*ret_addr), end)) {
 131                 unsigned long addr = *ret_addr;
 132
 133                 if (!__kernel_text_address(addr))
 134                         break;
 135
 136                 ops->address(data, addr, 1);
 137                 frame = frame->next_frame;
 138                 ret_addr = &frame->return_address;
 139                 print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
 140         }
 141
 142         return (unsigned long)frame;
 143 }
 144 EXPORT_SYMBOL_GPL(print_context_stack_bp);
 145
 146 static int print_trace_stack(void *data, char *name)
 147 {
 148         printk("%s <%s> ", (char *)data, name);
 149         return 0;
 150 }
 151
 152 /*
 153  * Print one address/symbol entries per line.
 154  */
 155 static void print_trace_address(void *data, unsigned long addr, int reliable)
 156 {
 157         touch_nmi_watchdog();
 158         printk(data);
 159         printk_stack_address(addr, reliable);
 160 }
 161
 162 static const struct stacktrace_ops print_trace_ops = {
 163         .stack                  = print_trace_stack,
 164         .address                = print_trace_address,
 165         .walk_stack             = print_context_stack,
 166 };
 167
 168 void
 169 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 170                 unsigned long *stack, unsigned long bp, char *log_lvl)
 171 {
 172         printk("%sCall Trace:\n", log_lvl);
 173         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 174 }
 175
 176 void show_trace(struct task_struct *task, struct pt_regs *regs,
 177                 unsigned long *stack, unsigned long bp)
 178 {
 179         show_trace_log_lvl(task, regs, stack, bp, "");
 180 }
 181
 182 void show_stack(struct task_struct *task, unsigned long *sp)
 183 {
 184         unsigned long bp = 0;
 185         unsigned long stack;
 186
 187         /*
 188          * Stack frames below this one aren't interesting.  Don't show them
 189          * if we're printing for %current.
 190          */
 191         if (!sp && (!task || task == current)) {
 192                 sp = &stack;
 193                 bp = stack_frame(current, NULL);
 194         }
 195
 196         show_stack_log_lvl(task, NULL, sp, bp, "");
 197 }
 198
 199 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
 200 static int die_owner = -1;
 201 static unsigned int die_nest_count;
 202
 203 unsigned long oops_begin(void)
 204 {
 205         int cpu;
 206         unsigned long flags;
 207
 208         oops_enter();
 209
 210         /* racy, but better than risking deadlock. */
 211         raw_local_irq_save(flags);
 212         cpu = smp_processor_id();
 213         if (!arch_spin_trylock(&die_lock)) {
 214                 if (cpu == die_owner)
 215                         /* nested oops. should stop eventually */;
 216                 else
 217                         arch_spin_lock(&die_lock);
 218         }
 219         die_nest_count++;
 220         die_owner = cpu;
 221         console_verbose();
 222         bust_spinlocks(1);
 223         return flags;
 224 }
 225 EXPORT_SYMBOL_GPL(oops_begin);
 226 NOKPROBE_SYMBOL(oops_begin);
 227
 228 void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 229 {
 230         if (regs && kexec_should_crash(current))
 231                 crash_kexec(regs);
 232
 233         bust_spinlocks(0);
 234         die_owner = -1;
 235         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 236         die_nest_count--;
 237         if (!die_nest_count)
 238                 /* Nest count reaches zero, release the lock. */
 239                 arch_spin_unlock(&die_lock);
 240         raw_local_irq_restore(flags);
 241         oops_exit();
 242
 243         if (!signr)
 244                 return;
 245         if (in_interrupt())
 246                 panic("Fatal exception in interrupt");
 247         if (panic_on_oops)
 248                 panic("Fatal exception");
 249         do_exit(signr);
 250 }
 251 NOKPROBE_SYMBOL(oops_end);
 252
 253 int __die(const char *str, struct pt_regs *regs, long err)
 254 {
 255 #ifdef CONFIG_X86_32
 256         unsigned short ss;
 257         unsigned long sp;
 258 #endif
 259         printk(KERN_DEFAULT
 260                "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 261 #ifdef CONFIG_PREEMPT
 262         printk("PREEMPT ");
 263 #endif
 264 #ifdef CONFIG_SMP
 265         printk("SMP ");
 266 #endif
 267 #ifdef CONFIG_DEBUG_PAGEALLOC
 268         printk("DEBUG_PAGEALLOC ");
 269 #endif
 270 #ifdef CONFIG_KASAN
 271         printk("KASAN");
 272 #endif
 273         printk("\n");
 274         if (notify_die(DIE_OOPS, str, regs, err,
 275                         current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)
 276                 return 1;
 277
 278         print_modules();
 279         show_regs(regs);
 280 #ifdef CONFIG_X86_32
 281         if (user_mode_vm(regs)) {
 282                 sp = regs->sp;
 283                 ss = regs->ss & 0xffff;
 284         } else {
 285                 sp = kernel_stack_pointer(regs);
 286                 savesegment(ss, ss);
 287         }
 288         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 289         print_symbol("%s", regs->ip);
 290         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 291 #else
 292         /* Executive summary in case the oops scrolled away */
 293         printk(KERN_ALERT "RIP ");
 294         printk_address(regs->ip);
 295         printk(" RSP <%016lx>\n", regs->sp);
 296 #endif
 297         return 0;
 298 }
 299 NOKPROBE_SYMBOL(__die);
 300
 301 /*
 302  * This is gone through when something in the kernel has done something bad
 303  * and is about to be terminated:
 304  */
 305 void die(const char *str, struct pt_regs *regs, long err)
 306 {
 307         unsigned long flags = oops_begin();
 308         int sig = SIGSEGV;
 309
 310         if (!user_mode_vm(regs))
 311                 report_bug(regs->ip, regs);
 312
 313         if (__die(str, regs, err))
 314                 sig = 0;
 315         oops_end(flags, regs, sig);
 316 }
 317
 318 static int __init kstack_setup(char *s)
 319 {
 320         ssize_t ret;
 321         unsigned long val;
 322
 323         if (!s)
 324                 return -EINVAL;
 325
 326         ret = kstrtoul(s, 0, &val);
 327         if (ret)
 328                 return ret;
 329         kstack_depth_to_print = val;
 330         return 0;
 331 }
 332 early_param("kstack", kstack_setup);
 333
 334 static int __init code_bytes_setup(char *s)
 335 {
 336         ssize_t ret;
 337         unsigned long val;
 338
 339         if (!s)
 340                 return -EINVAL;
 341
 342         ret = kstrtoul(s, 0, &val);
 343         if (ret)
 344                 return ret;
 345
 346         code_bytes = val;
 347         if (code_bytes > 8192)
 348                 code_bytes = 8192;
 349
 350         return 1;
 351 }
 352 __setup("code_bytes=", code_bytes_setup);