src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c

@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.

@@ -101,11 +101,11 @@
     destroy_map_info(ph);
     free(ph->core);
   }
 }
 
-static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz) {
+static map_info* allocate_init_map(int fd, off_t offset, uintptr_t vaddr, size_t memsz, uint32_t flags) {
   map_info* map;
   if ( (map = (map_info*) calloc(1, sizeof(map_info))) == NULL) {
     print_debug("can't allocate memory for map_info\n");
     return NULL;
   }

@@ -113,18 +113,19 @@
   // initialize map
   map->fd     = fd;
   map->offset = offset;
   map->vaddr  = vaddr;
   map->memsz  = memsz;
+  map->flags  = flags;
   return map;
 }
 
 // add map info with given fd, offset, vaddr and memsz
 static map_info* add_map_info(struct ps_prochandle* ph, int fd, off_t offset,
-                             uintptr_t vaddr, size_t memsz) {
+                             uintptr_t vaddr, size_t memsz, uint32_t flags) {
   map_info* map;
-  if ((map = allocate_init_map(fd, offset, vaddr, memsz)) == NULL) {
+  if ((map = allocate_init_map(fd, offset, vaddr, memsz, flags)) == NULL) {
     return NULL;
   }
 
   // add this to map list
   map->next  = ph->core->maps;

@@ -137,11 +138,11 @@
 // Part of the class sharing workaround
 static map_info* add_class_share_map_info(struct ps_prochandle* ph, off_t offset,
                              uintptr_t vaddr, size_t memsz) {
   map_info* map;
   if ((map = allocate_init_map(ph->core->classes_jsa_fd,
-                               offset, vaddr, memsz)) == NULL) {
+                               offset, vaddr, memsz, PF_R)) == NULL) {
     return NULL;
   }
 
   map->next = ph->core->class_share_maps;
   ph->core->class_share_maps = map;

@@ -671,11 +672,11 @@
             break;
 
          case PT_LOAD: {
             if (core_php->p_filesz != 0) {
                if (add_map_info(ph, ph->core->core_fd, core_php->p_offset,
-                  core_php->p_vaddr, core_php->p_filesz) == NULL) goto err;
+                  core_php->p_vaddr, core_php->p_filesz, core_php->p_flags) == NULL) goto err;
             }
             break;
          }
       }
 

@@ -710,14 +711,25 @@
       uintptr_t target_vaddr = lib_php->p_vaddr + lib_base;
       map_info *existing_map = core_lookup(ph, target_vaddr);
 
       if (existing_map == NULL){
         if (add_map_info(ph, lib_fd, lib_php->p_offset,
-                          target_vaddr, lib_php->p_memsz) == NULL) {
+                          target_vaddr, lib_php->p_memsz, lib_php->p_flags) == NULL) {
           goto err;
         }
+      } else if (lib_php->p_flags != existing_map->flags) {
+        // Access flags for this memory region are different between the library
+        // and coredump. It might be caused by mprotect() call at runtime.
+        // We should respect the coredump.
+        continue;
       } else {
+        // Read only segments in ELF should not be any different from PT_LOAD segments
+        // in the coredump.
+        // Also the first page of the ELF header might be included
+        // in the coredump (See JDK-7133122).
+        // Thus we need to replace the PT_LOAD segment with the library version.
+        //
         // Coredump stores value of p_memsz elf field
         // rounded up to page boundary.
 
         if ((existing_map->memsz != page_size) &&
             (existing_map->fd != lib_fd) &&

@@ -780,11 +792,11 @@
 
       // add mappings for PT_LOAD segments
     case PT_LOAD: {
       // add only non-writable segments of non-zero filesz
       if (!(exec_php->p_flags & PF_W) && exec_php->p_filesz != 0) {
-        if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz) == NULL) goto err;
+        if (add_map_info(ph, ph->core->exec_fd, exec_php->p_offset, exec_php->p_vaddr, exec_php->p_filesz, exec_php->p_flags) == NULL) goto err;
       }
       break;
     }
 
     // read the interpreter and it's segments