arch/s390/kernel/stacktrace.c

   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 }