1 /* 2 * Stack trace management functions 3 * 4 * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> 5 */ 6 #include <linux/sched.h> 7 #include <linux/stacktrace.h> 8 #include <linux/module.h> 9 #include <linux/uaccess.h> 10 #include <asm/stacktrace.h> 11 12 static int save_stack_stack(void *data, char *name) 13 { 14 return 0; 15 } 16 17 static void 18 __save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched) 19 { 20 struct stack_trace *trace = data; 21 #ifdef CONFIG_FRAME_POINTER 22 if (!reliable) 23 return; 24 #endif 25 if (nosched && in_sched_functions(addr)) 26 return; 27 if (trace->skip > 0) { 28 trace->skip--; 29 return; 30 } 31 if (trace->nr_entries < trace->max_entries) 32 trace->entries[trace->nr_entries++] = addr; 33 } 34 35 static void save_stack_address(void *data, unsigned long addr, int reliable) 36 { 37 return __save_stack_address(data, addr, reliable, false); 38 } 39 40 static void 41 save_stack_address_nosched(void *data, unsigned long addr, int reliable) 42 { 43 return __save_stack_address(data, addr, reliable, true); 44 } 45 46 static const struct stacktrace_ops save_stack_ops = { 47 .stack = save_stack_stack, 48 .address = save_stack_address, 49 .walk_stack = print_context_stack, 50 }; 51 52 static const struct stacktrace_ops save_stack_ops_nosched = { 53 .stack = save_stack_stack, 54 .address = save_stack_address_nosched, 55 .walk_stack = print_context_stack, 56 }; 57 58 /* 59 * Save stack-backtrace addresses into a stack_trace buffer. 60 */ 61 void save_stack_trace(struct stack_trace *trace) 62 { 63 dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace); 64 if (trace->nr_entries < trace->max_entries) 65 trace->entries[trace->nr_entries++] = ULONG_MAX; 66 } 67 EXPORT_SYMBOL_GPL(save_stack_trace); 68 69 void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) 70 { 71 dump_trace(current, regs, NULL, 0, &save_stack_ops, trace); 72 if (trace->nr_entries < trace->max_entries) 73 trace->entries[trace->nr_entries++] = ULONG_MAX; 74 } 75 76 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 77 { 78 dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace); 79 if (trace->nr_entries < trace->max_entries) 80 trace->entries[trace->nr_entries++] = ULONG_MAX; 81 } 82 EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 83 84 /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */ 85 86 struct stack_frame_user { 87 const void __user *next_fp; 88 unsigned long ret_addr; 89 }; 90 91 static int 92 copy_stack_frame(const void __user *fp, struct stack_frame_user *frame) 93 { 94 int ret; 95 96 if (!access_ok(VERIFY_READ, fp, sizeof(*frame))) 97 return 0; 98 99 ret = 1; 100 pagefault_disable(); 101 if (__copy_from_user_inatomic(frame, fp, sizeof(*frame))) 102 ret = 0; 103 pagefault_enable(); 104 105 return ret; 106 } 107 108 static inline void __save_stack_trace_user(struct stack_trace *trace) 109 { 110 const struct pt_regs *regs = task_pt_regs(current); 111 const void __user *fp = (const void __user *)regs->bp; 112 113 if (trace->nr_entries < trace->max_entries) 114 trace->entries[trace->nr_entries++] = regs->ip; 115 116 while (trace->nr_entries < trace->max_entries) { 117 struct stack_frame_user frame; 118 119 frame.next_fp = NULL; 120 frame.ret_addr = 0; 121 if (!copy_stack_frame(fp, &frame)) 122 break; 123 if ((unsigned long)fp < regs->sp) 124 break; 125 if (frame.ret_addr) { 126 trace->entries[trace->nr_entries++] = 127 frame.ret_addr; 128 } 129 if (fp == frame.next_fp) 130 break; 131 fp = frame.next_fp; 132 } 133 } 134 135 void save_stack_trace_user(struct stack_trace *trace) 136 { 137 /* 138 * Trace user stack if we are not a kernel thread 139 */ 140 if (current->mm) { 141 __save_stack_trace_user(trace); 142 } 143 if (trace->nr_entries < trace->max_entries) 144 trace->entries[trace->nr_entries++] = ULONG_MAX; 145 } 146 147