1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Stack trace management functions 4 * 5 * Copyright IBM Corp. 2006 6 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> 7 */ 8 9 #include <linux/stacktrace.h> 10 #include <asm/stacktrace.h> 11 #include <asm/unwind.h> 12 #include <asm/kprobes.h> 13 14 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, 15 struct task_struct *task, struct pt_regs *regs) 16 { 17 struct unwind_state state; 18 unsigned long addr; 19 20 unwind_for_each_frame(&state, task, regs, 0) { 21 addr = unwind_get_return_address(&state); 22 if (!addr || !consume_entry(cookie, addr, false)) 23 break; 24 } 25 } 26 27 /* 28 * This function returns an error if it detects any unreliable features of the 29 * stack. Otherwise it guarantees that the stack trace is reliable. 30 * 31 * If the task is not 'current', the caller *must* ensure the task is inactive. 32 */ 33 int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, 34 void *cookie, struct task_struct *task) 35 { 36 struct unwind_state state; 37 unsigned long addr; 38 39 unwind_for_each_frame(&state, task, NULL, 0) { 40 if (state.stack_info.type != STACK_TYPE_TASK) 41 return -EINVAL; 42 43 if (state.regs) 44 return -EINVAL; 45 46 addr = unwind_get_return_address(&state); 47 if (!addr) 48 return -EINVAL; 49 50 #ifdef CONFIG_KPROBES 51 /* 52 * Mark stacktraces with kretprobed functions on them 53 * as unreliable. 54 */ 55 if (state.ip == (unsigned long)kretprobe_trampoline) 56 return -EINVAL; 57 #endif 58 59 if (!consume_entry(cookie, addr, false)) 60 return -EINVAL; 61 } 62 63 /* Check for stack corruption */ 64 if (unwind_error(&state)) 65 return -EINVAL; 66 return 0; 67 } 68