1 /* This testcase is part of GDB, the GNU debugger. 2 3 Copyright 2014-2023 Free Software Foundation, Inc. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include <sys/mman.h> 20 #include <unistd.h> 21 #include <assert.h> 22 23 void *global_invalid_ptr = NULL; 24 25 void 26 func2 (void) 27 { 28 /* Replace the current stack pointer and frame pointer with the invalid 29 pointer. */ 30 asm ("mov %0, %%rsp\n\tmov %0, %%rbp" : : "r" (global_invalid_ptr)); 31 32 /* Create a label for a breakpoint. */ 33 asm (".global breakpt\nbreakpt:"); 34 } 35 36 void 37 func1 (void *ptr) 38 { 39 global_invalid_ptr = ptr; 40 func2 (); 41 } 42 43 /* Finds and returns an invalid pointer, mmaps in a page, grabs a pointer 44 to it then unmaps the page again. This is almost certainly "undefined" 45 behaviour, but should be good enough for this small test program. */ 46 47 static void * 48 make_invalid_ptr (void) 49 { 50 int page_size, ans; 51 void *ptr; 52 53 page_size = getpagesize (); 54 ptr = mmap (0, page_size, PROT_NONE, 55 MAP_PRIVATE | MAP_ANONYMOUS, 56 -1, 0); 57 assert (ptr != MAP_FAILED); 58 ans = munmap (ptr, page_size); 59 assert (ans == 0); 60 61 return ptr; 62 } 63 64 int 65 main (void) 66 { 67 void *invalid_ptr; 68 69 invalid_ptr = make_invalid_ptr (); 70 func1 (invalid_ptr); 71 72 return 0; 73 } 74