| /* |
| * Stack trace management functions |
| * |
| * Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| */ |
| #include <linux/sched.h> |
| #include <linux/stacktrace.h> |
| #include <linux/export.h> |
| #include <linux/uaccess.h> |
| #include <asm/stacktrace.h> |
| |
| static int save_stack_stack(void *data, char *name) |
| { |
| return 0; |
| } |
| |
| static int |
| __save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched) |
| { |
| struct stack_trace *trace = data; |
| #ifdef CONFIG_FRAME_POINTER |
| if (!reliable) |
| return 0; |
| #endif |
| if (nosched && in_sched_functions(addr)) |
| return 0; |
| if (trace->skip > 0) { |
| trace->skip--; |
| return 0; |
| } |
| if (trace->nr_entries < trace->max_entries) { |
| trace->entries[trace->nr_entries++] = addr; |
| return 0; |
| } else { |
| return -1; /* no more room, stop walking the stack */ |
| } |
| } |
| |
| static int save_stack_address(void *data, unsigned long addr, int reliable) |
| { |
| return __save_stack_address(data, addr, reliable, false); |
| } |
| |
| static int |
| save_stack_address_nosched(void *data, unsigned long addr, int reliable) |
| { |
| return __save_stack_address(data, addr, reliable, true); |
| } |
| |
| static const struct stacktrace_ops save_stack_ops = { |
| .stack = save_stack_stack, |
| .address = save_stack_address, |
| .walk_stack = print_context_stack, |
| }; |
| |
| static const struct stacktrace_ops save_stack_ops_nosched = { |
| .stack = save_stack_stack, |
| .address = save_stack_address_nosched, |
| .walk_stack = print_context_stack, |
| }; |
| |
| /* |
| * Save stack-backtrace addresses into a stack_trace buffer. |
| */ |
| void save_stack_trace(struct stack_trace *trace) |
| { |
| dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace); |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = ULONG_MAX; |
| } |
| EXPORT_SYMBOL_GPL(save_stack_trace); |
| |
| void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) |
| { |
| dump_trace(current, regs, NULL, 0, &save_stack_ops, trace); |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = ULONG_MAX; |
| } |
| |
| void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) |
| { |
| dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace); |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = ULONG_MAX; |
| } |
| EXPORT_SYMBOL_GPL(save_stack_trace_tsk); |
| |
| /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */ |
| |
| struct stack_frame_user { |
| const void __user *next_fp; |
| unsigned long ret_addr; |
| }; |
| |
| static int |
| copy_stack_frame(const void __user *fp, struct stack_frame_user *frame) |
| { |
| int ret; |
| |
| if (!access_ok(VERIFY_READ, fp, sizeof(*frame))) |
| return 0; |
| |
| ret = 1; |
| pagefault_disable(); |
| if (__copy_from_user_inatomic(frame, fp, sizeof(*frame))) |
| ret = 0; |
| pagefault_enable(); |
| |
| return ret; |
| } |
| |
| static inline void __save_stack_trace_user(struct stack_trace *trace) |
| { |
| const struct pt_regs *regs = task_pt_regs(current); |
| const void __user *fp = (const void __user *)regs->bp; |
| |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = regs->ip; |
| |
| while (trace->nr_entries < trace->max_entries) { |
| struct stack_frame_user frame; |
| |
| frame.next_fp = NULL; |
| frame.ret_addr = 0; |
| if (!copy_stack_frame(fp, &frame)) |
| break; |
| if ((unsigned long)fp < regs->sp) |
| break; |
| if (frame.ret_addr) { |
| trace->entries[trace->nr_entries++] = |
| frame.ret_addr; |
| } |
| if (fp == frame.next_fp) |
| break; |
| fp = frame.next_fp; |
| } |
| } |
| |
| void save_stack_trace_user(struct stack_trace *trace) |
| { |
| /* |
| * Trace user stack if we are not a kernel thread |
| */ |
| if (current->mm) { |
| __save_stack_trace_user(trace); |
| } |
| if (trace->nr_entries < trace->max_entries) |
| trace->entries[trace->nr_entries++] = ULONG_MAX; |
| } |
| |