diff --git a/debuggerd/arm/machine.c b/debuggerd/arm/machine.c
index d941684..ca45c9b 100644
--- a/debuggerd/arm/machine.c
+++ b/debuggerd/arm/machine.c
@@ -87,7 +87,7 @@
     }
 }
 
-void dump_registers(ptrace_context_t* context __attribute((unused)),
+void dump_registers(const ptrace_context_t* context __attribute((unused)),
         int tfd, pid_t tid, bool at_fault)
 {
     struct pt_regs r;
@@ -125,7 +125,7 @@
 #endif
 }
 
-void dump_thread(ptrace_context_t* context, int tfd, pid_t tid, bool at_fault) {
+void dump_thread(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault) {
     dump_registers(context, tfd, tid, at_fault);
 
     dump_backtrace_and_stack(context, tfd, tid, at_fault);
diff --git a/debuggerd/debuggerd.c b/debuggerd/debuggerd.c
index 5a180f1..20ffc13 100644
--- a/debuggerd/debuggerd.c
+++ b/debuggerd/debuggerd.c
@@ -114,12 +114,12 @@
     return "?";
 }
 
-static void dump_fault_addr(int tfd, pid_t pid, int sig)
+static void dump_fault_addr(int tfd, pid_t tid, int sig)
 {
     siginfo_t si;
 
     memset(&si, 0, sizeof(si));
-    if(ptrace(PTRACE_GETSIGINFO, pid, 0, &si)){
+    if(ptrace(PTRACE_GETSIGINFO, tid, 0, &si)){
         _LOG(tfd, false, "cannot get siginfo: %s\n", strerror(errno));
     } else if (signal_has_address(sig)) {
         _LOG(tfd, false, "signal %d (%s), code %d (%s), fault addr %08x\n",
@@ -157,7 +157,7 @@
 }
 
 /* Return true if some thread is not detached cleanly */
-static bool dump_sibling_thread_report(ptrace_context_t* context,
+static bool dump_sibling_thread_report(const ptrace_context_t* context,
         int tfd, pid_t pid, pid_t tid) {
     char task_path[64];
     snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
@@ -361,7 +361,7 @@
 
     dump_crash_banner(tfd, pid, tid, signal);
 
-    ptrace_context_t* context = load_ptrace_context(pid);
+    ptrace_context_t* context = load_ptrace_context(tid);
 
     dump_thread(context, tfd, tid, true);
 
diff --git a/debuggerd/machine.h b/debuggerd/machine.h
index f9ca6bd..6049b69 100644
--- a/debuggerd/machine.h
+++ b/debuggerd/machine.h
@@ -20,6 +20,6 @@
 #include <corkscrew/backtrace.h>
 #include <sys/types.h>
 
-void dump_thread(ptrace_context_t* context, int tfd, pid_t tid, bool at_fault);
+void dump_thread(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault);
 
 #endif // _DEBUGGERD_MACHINE_H
diff --git a/debuggerd/utility.c b/debuggerd/utility.c
index c0fb13a..64e5980 100644
--- a/debuggerd/utility.c
+++ b/debuggerd/utility.c
@@ -57,8 +57,8 @@
     }
 }
 
-static void dump_backtrace(ptrace_context_t* context __attribute((unused)),
-        int tfd, int pid __attribute((unused)), bool at_fault,
+static void dump_backtrace(const ptrace_context_t* context __attribute((unused)),
+        int tfd, pid_t tid __attribute((unused)), bool at_fault,
         const backtrace_frame_t* backtrace, size_t frames) {
     _LOG(tfd, !at_fault, "\nbacktrace:\n");
 
@@ -66,7 +66,7 @@
     get_backtrace_symbols_ptrace(context, backtrace, frames, backtrace_symbols);
     for (size_t i = 0; i < frames; i++) {
         const backtrace_symbol_t* symbol = &backtrace_symbols[i];
-        const char* map_name = symbol->map_info ? symbol->map_info->name : "<unknown>";
+        const char* map_name = symbol->map_name ? symbol->map_name : "<unknown>";
         const char* symbol_name = symbol->demangled_name ? symbol->demangled_name : symbol->name;
         if (symbol_name) {
             _LOG(tfd, !at_fault, "    #%02d  pc %08x  %s (%s)\n",
@@ -79,11 +79,11 @@
     free_backtrace_symbols(backtrace_symbols, frames);
 }
 
-static void dump_stack_segment(ptrace_context_t* context, int tfd, int pid,
+static void dump_stack_segment(const ptrace_context_t* context, int tfd, pid_t tid,
         bool only_in_tombstone, uintptr_t* sp, size_t words, int label) {
     for (size_t i = 0; i < words; i++) {
         uint32_t stack_content;
-        if (!try_get_word(pid, *sp, &stack_content)) {
+        if (!try_get_word_ptrace(tid, *sp, &stack_content)) {
             break;
         }
 
@@ -116,7 +116,7 @@
     }
 }
 
-static void dump_stack(ptrace_context_t* context, int tfd, int pid, bool at_fault,
+static void dump_stack(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault,
         const backtrace_frame_t* backtrace, size_t frames) {
     bool have_first = false;
     size_t first, last;
@@ -138,7 +138,7 @@
     // Dump a few words before the first frame.
     bool only_in_tombstone = !at_fault;
     uintptr_t sp = backtrace[first].stack_top - STACK_WORDS * sizeof(uint32_t);
-    dump_stack_segment(context, tfd, pid, only_in_tombstone, &sp, STACK_WORDS, -1);
+    dump_stack_segment(context, tfd, tid, only_in_tombstone, &sp, STACK_WORDS, -1);
 
     // Dump a few words from all successive frames.
     // Only log the first 3 frames, put the rest in the tombstone.
@@ -152,7 +152,7 @@
             only_in_tombstone = true;
         }
         if (i == last) {
-            dump_stack_segment(context, tfd, pid, only_in_tombstone, &sp, STACK_WORDS, i);
+            dump_stack_segment(context, tfd, tid, only_in_tombstone, &sp, STACK_WORDS, i);
             if (sp < frame->stack_top + frame->stack_size) {
                 _LOG(tfd, only_in_tombstone, "         ........  ........\n");
             }
@@ -163,12 +163,13 @@
             } else if (words > STACK_WORDS) {
                 words = STACK_WORDS;
             }
-            dump_stack_segment(context, tfd, pid, only_in_tombstone, &sp, words, i);
+            dump_stack_segment(context, tfd, tid, only_in_tombstone, &sp, words, i);
         }
     }
 }
 
-void dump_backtrace_and_stack(ptrace_context_t* context, int tfd, pid_t tid, bool at_fault) {
+void dump_backtrace_and_stack(const ptrace_context_t* context, int tfd, pid_t tid,
+        bool at_fault) {
     backtrace_frame_t backtrace[STACK_DEPTH];
     ssize_t frames = unwind_backtrace_ptrace(tid, context, backtrace, 0, STACK_DEPTH);
     if (frames > 0) {
@@ -237,7 +238,7 @@
     }
 }
 
-void dump_nearby_maps(ptrace_context_t* context, int tfd, pid_t tid) {
+void dump_nearby_maps(const ptrace_context_t* context, int tfd, pid_t tid) {
     siginfo_t si;
     memset(&si, 0, sizeof(si));
     if (ptrace(PTRACE_GETSIGINFO, tid, 0, &si)) {
diff --git a/debuggerd/utility.h b/debuggerd/utility.h
index 879c8b4..39f91cb 100644
--- a/debuggerd/utility.h
+++ b/debuggerd/utility.h
@@ -52,7 +52,7 @@
 /*
  * Dumps the backtrace and contents of the stack.
  */
-void dump_backtrace_and_stack(ptrace_context_t* context, int tfd, pid_t pid, bool at_fault);
+void dump_backtrace_and_stack(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault);
 
 /*
  * Dumps a few bytes of memory, starting a bit before and ending a bit
@@ -66,7 +66,7 @@
  *
  * This only makes sense to do on the thread that crashed.
  */
-void dump_nearby_maps(ptrace_context_t* context, int tfd, pid_t tid);
+void dump_nearby_maps(const ptrace_context_t* context, int tfd, pid_t tid);
 
 
 #endif // _DEBUGGERD_UTILITY_H
diff --git a/debuggerd/x86/machine.c b/debuggerd/x86/machine.c
index 57f51c8..2729c7e 100644
--- a/debuggerd/x86/machine.c
+++ b/debuggerd/x86/machine.c
@@ -39,12 +39,12 @@
 #include "../machine.h"
 #include "../utility.h"
 
-static void dump_registers(ptrace_context_t* context __attribute((unused)),
-        int tfd, pid_t pid, bool at_fault) {
+static void dump_registers(const ptrace_context_t* context __attribute((unused)),
+        int tfd, pid_t tid, bool at_fault) {
     struct pt_regs_x86 r;
     bool only_in_tombstone = !at_fault;
 
-    if(ptrace(PTRACE_GETREGS, pid, 0, &r)) {
+    if(ptrace(PTRACE_GETREGS, tid, 0, &r)) {
         _LOG(tfd, only_in_tombstone, "cannot get registers: %s\n", strerror(errno));
         return;
     }
@@ -61,7 +61,7 @@
          r.eip, r.ebp, r.esp, r.eflags);
 }
 
-void dump_thread(ptrace_context_t* context, int tfd, pid_t tid, bool at_fault) {
+void dump_thread(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault) {
     dump_registers(context, tfd, tid, at_fault);
 
     dump_backtrace_and_stack(context, tfd, tid, at_fault);