gdbserver/Windows: crash during connection establishment phase

On Windows, starting a new process with GDBserver seems to work,
in the sense that the program does get started, and GDBserver
confirms that it is listening for GDB to connect. However, as soon as
GDB establishes the connection with GDBserver, and starts discussing
with it, GDBserver crashes, with a SEGV.

This SEGV occurs in remote-utils.c::prepare_resume_reply...

  | regp = current_target_desc ()->expedite_regs;
  | [...]
  | while (*regp)

... because, in our case, REGP is NULL.

This patches fixes the issues by adding a parameter to init_target_desc,
in order to make sure that we always provide the list of registers when
we initialize a target description.

gdb/ChangeLog:

        PR server/23158:
        * regformats/regdat.sh: Adjust script, following the addition
        of the new expedite_regs parameter to init_target_desc.

gdb/gdbserver/ChangeLog:

        PR server/23158:
        * tdesc.h (init_target_desc) <expedite_regs>: New parameter.
        * tdesc.c (init_target_desc) <expedite_regs>: New parameter.
        Use it to set the expedite_regs field in the given tdesc.
        * x86-tdesc.h: New file.
        * linux-aarch64-tdesc.c (aarch64_linux_read_description):
        Adjust following the addition of the new expedite_regs parameter
        to init_target_desc.
        * linux-tic6x-low.c (tic6x_read_description): Likewise.
        * linux-x86-tdesc.c: #include "x86-tdesc.h".
        (i386_linux_read_description, amd64_linux_read_description):
        Adjust following the addition of the new expedite_regs parameter
        to init_target_desc.
        * lynx-i386-low.c: #include "x86-tdesc.h".
        (lynx_i386_arch_setup): Adjust following the addition of the new
        expedite_regs parameter to init_target_desc.
        * nto-x86-low.c: #include "x86-tdesc.h".
        (nto_x86_arch_setup): Adjust following the addition of the new
        expedite_regs parameter to init_target_desc.
        * win32-i386-low.c: #include "x86-tdesc.h".
        (i386_arch_setup): Adjust following the addition of the new
        expedite_regs parameter to init_target_desc.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 300e90cfecbd8741ee553df90018c0eb8f1ebc55..3467467383a834a8d31f4aac9d0a7664a542a1e3 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2018-05-10  Joel Brobecker  <brobecker@adacore.com>
+
+       PR server/23158:
+       * regformats/regdat.sh: Adjust script, following the addition
+       of the new expedite_regs parameter to init_target_desc.
+
 2018-05-10  Omair Javaid  <omair.javaid@linaro.org>
     
        PR gdb/23127

diff --git a/gdb/gdbserver/ChangeLog b/gdb/gdbserver/ChangeLog
index 6b6f8fc349a9a214eae7a1bc154f39aaf8bcf5e2..9ead1220a7c39fccc018df1066c827a8c073d454 100644 (file)
--- a/gdb/gdbserver/ChangeLog
+++ b/gdb/gdbserver/ChangeLog
@@ -1,3 +1,28 @@
+2018-05-10  Joel Brobecker  <brobecker@adacore.com>
+
+       PR server/23158:
+       * tdesc.h (init_target_desc) <expedite_regs>: New parameter.
+       * tdesc.c (init_target_desc) <expedite_regs>: New parameter.
+       Use it to set the expedite_regs field in the given tdesc.
+       * x86-tdesc.h: New file.
+       * linux-aarch64-tdesc.c (aarch64_linux_read_description):
+       Adjust following the addition of the new expedite_regs parameter
+       to init_target_desc.
+       * linux-tic6x-low.c (tic6x_read_description): Likewise.
+       * linux-x86-tdesc.c: #include "x86-tdesc.h".
+       (i386_linux_read_description, amd64_linux_read_description):
+       Adjust following the addition of the new expedite_regs parameter
+       to init_target_desc.
+       * lynx-i386-low.c: #include "x86-tdesc.h".
+       (lynx_i386_arch_setup): Adjust following the addition of the new
+       expedite_regs parameter to init_target_desc.
+       * nto-x86-low.c: #include "x86-tdesc.h".
+       (nto_x86_arch_setup): Adjust following the addition of the new
+       expedite_regs parameter to init_target_desc.
+       * win32-i386-low.c: #include "x86-tdesc.h".
+       (i386_arch_setup): Adjust following the addition of the new
+       expedite_regs parameter to init_target_desc.
+
 2018-05-10  Joel Brobecker  <brobecker@adacore.com>
 
        PR server/23158:

diff --git a/gdb/gdbserver/linux-aarch64-tdesc.c b/gdb/gdbserver/linux-aarch64-tdesc.c
index 9f7b9e5c854d4a4793058406f21cd02bc65e36d6..f433038351ec3d0ed06d210fdda8145b9f990008 100644 (file)
--- a/gdb/gdbserver/linux-aarch64-tdesc.c
+++ b/gdb/gdbserver/linux-aarch64-tdesc.c
@@ -34,12 +34,8 @@ aarch64_linux_read_description ()
     {
       *tdesc = aarch64_create_target_description ();
 
-      init_target_desc (*tdesc);
-
-#ifndef IN_PROCESS_AGENT
       static const char *expedite_regs_aarch64[] = { "x29", "sp", "pc", NULL };
-      (*tdesc)->expedite_regs = expedite_regs_aarch64;
-#endif
+      init_target_desc (*tdesc, expedite_regs_aarch64);
     }
 
   return *tdesc;

diff --git a/gdb/gdbserver/linux-tic6x-low.c b/gdb/gdbserver/linux-tic6x-low.c
index e1df59fefa8634fc2c921397af56e5381d3b76b7..d90bbcfe51fa35af428b7f1308916bd0cf9efeab 100644 (file)
--- a/gdb/gdbserver/linux-tic6x-low.c
+++ b/gdb/gdbserver/linux-tic6x-low.c
@@ -199,10 +199,8 @@ tic6x_read_description (enum c6x_feature feature)
   if (*tdesc == NULL)
     {
       *tdesc = tic6x_create_target_description (feature);
-      init_target_desc (*tdesc);
-
       static const char *expedite_regs[] = { "A15", "PC", NULL };
-      (*tdesc)->expedite_regs = expedite_regs;
+      init_target_desc (*tdesc, expedite_regs);
     }
 
   return *tdesc;

diff --git a/gdb/gdbserver/linux-x86-tdesc.c b/gdb/gdbserver/linux-x86-tdesc.c
index 47b847619e3173a97d249221194df4aaf3ac23d2..358659b29510bb6002307fe36a7c50ac2f8deb22 100644 (file)
--- a/gdb/gdbserver/linux-x86-tdesc.c
+++ b/gdb/gdbserver/linux-x86-tdesc.c
@@ -25,6 +25,7 @@
 #ifdef __x86_64__
 #include "arch/amd64.h"
 #endif
+#include "x86-tdesc.h"
 
 /* Return the right x86_linux_tdesc index for a given XCR0.  Return
    X86_TDESC_LAST if can't find a match.  */
@@ -88,12 +89,7 @@ i386_linux_read_description (uint64_t xcr0)
     {
       *tdesc = i386_create_target_description (xcr0, true);
 
-      init_target_desc (*tdesc);
-
-#ifndef IN_PROCESS_AGENT
-      static const char *expedite_regs_i386[] = { "ebp", "esp", "eip", NULL };
-      (*tdesc)->expedite_regs = expedite_regs_i386;
-#endif
+      init_target_desc (*tdesc, i386_expedite_regs);
     }
 
   return *tdesc;;
@@ -124,12 +120,7 @@ amd64_linux_read_description (uint64_t xcr0, bool is_x32)
     {
       *tdesc = amd64_create_target_description (xcr0, is_x32, true);
 
-      init_target_desc (*tdesc);
-
-#ifndef IN_PROCESS_AGENT
-      static const char *expedite_regs_amd64[] = { "rbp", "rsp", "rip", NULL };
-      (*tdesc)->expedite_regs = expedite_regs_amd64;
-#endif
+      init_target_desc (*tdesc, amd64_expedite_regs);
     }
   return *tdesc;
 }

diff --git a/gdb/gdbserver/lynx-i386-low.c b/gdb/gdbserver/lynx-i386-low.c
index c7b4fe44e67d82eb41bc49a22bb234422dd4207b..37c0dc97470c9dd305771e91e5c3c68287285cc4 100644 (file)
--- a/gdb/gdbserver/lynx-i386-low.c
+++ b/gdb/gdbserver/lynx-i386-low.c
@@ -21,6 +21,7 @@
 #include <sys/ptrace.h>
 #include "x86-xstate.h"
 #include "arch/i386.h"
+#include "x86-tdesc.h"
 
 /* The following two typedefs are defined in a .h file which is not
    in the standard include path (/sys/include/family/x86/ucontext.h),
@@ -296,7 +297,7 @@ lynx_i386_arch_setup (void)
   struct target_desc *tdesc
     = i386_create_target_description (X86_XSTATE_SSE_MASK, false);
 
-  init_target_desc (tdesc);
+  init_target_desc (tdesc, i386_expedite_regs);
 
   lynx_tdesc = tdesc;
 }

diff --git a/gdb/gdbserver/nto-x86-low.c b/gdb/gdbserver/nto-x86-low.c
index b15c208e7707d18ec3c05e5e4486c37527c6ccd4..81c3c6a7adbf41cf498a2f0e2fc6025178470df6 100644 (file)
--- a/gdb/gdbserver/nto-x86-low.c
+++ b/gdb/gdbserver/nto-x86-low.c
@@ -25,6 +25,7 @@
 #include <x86/context.h>
 #include "x86-xstate.h"
 #include "arch/i386.h"
+#include "x86-tdesc.h"
 
 const unsigned char x86_breakpoint[] = { 0xCC };
 #define x86_breakpoint_len 1
@@ -90,7 +91,7 @@ nto_x86_arch_setup (void)
   struct target_desc *tdesc
     = i386_create_target_description (X86_XSTATE_SSE_MASK, false);
 
-  init_target_desc (tdesc);
+  init_target_desc (tdesc, i386_expedite_regs);
 
   nto_tdesc = tdesc;
 }

diff --git a/gdb/gdbserver/tdesc.c b/gdb/gdbserver/tdesc.c
index 92524b3dec89b29a3a65f34de422faefd09da0b9..d03508373b3fe42822d7cea92564dcfea2356167 100644 (file)
--- a/gdb/gdbserver/tdesc.c
+++ b/gdb/gdbserver/tdesc.c
@@ -60,7 +60,8 @@ void target_desc::accept (tdesc_element_visitor &v) const
 }
 
 void
-init_target_desc (struct target_desc *tdesc)
+init_target_desc (struct target_desc *tdesc,
+                 const char **expedite_regs)
 {
   int offset = 0;
 
@@ -86,6 +87,10 @@ init_target_desc (struct target_desc *tdesc)
   /* Make sure PBUFSIZ is large enough to hold a full register
      packet.  */
   gdb_assert (2 * tdesc->registers_size + 32 <= PBUFSIZ);
+
+#ifndef IN_PROCESS_AGENT
+  tdesc->expedite_regs = expedite_regs;
+#endif
 }
 
 struct target_desc *

diff --git a/gdb/gdbserver/tdesc.h b/gdb/gdbserver/tdesc.h
index 61a3e4ecdd2ce5fbbca2e0f196bb3243c7d55b47..989c12896ef5ac36a816a413a260fb3a06a56c69 100644 (file)
--- a/gdb/gdbserver/tdesc.h
+++ b/gdb/gdbserver/tdesc.h
@@ -82,9 +82,11 @@ public:
 void copy_target_description (struct target_desc *dest,
                              const struct target_desc *src);
 
-/* Initialize TDESC.  */
+/* Initialize TDESC, and then set its expedite_regs field to
+   EXPEDITE_REGS.  */
 
-void init_target_desc (struct target_desc *tdesc);
+void init_target_desc (struct target_desc *tdesc,
+                      const char **expedite_regs);
 
 /* Return the current inferior's target description.  Never returns
    NULL.  */

diff --git a/gdb/gdbserver/win32-i386-low.c b/gdb/gdbserver/win32-i386-low.c
index a242f7258af194ac04ab09011100168ca0a70d83..16fe2c85b2a081d45112cf2225f653cf3dbc7fba 100644 (file)
--- a/gdb/gdbserver/win32-i386-low.c
+++ b/gdb/gdbserver/win32-i386-low.c
@@ -24,6 +24,7 @@
 #endif
 #include "arch/i386.h"
 #include "tdesc.h"
+#include "x86-tdesc.h"
 
 #ifndef CONTEXT_EXTENDED_REGISTERS
 #define CONTEXT_EXTENDED_REGISTERS 0
@@ -436,11 +437,13 @@ i386_arch_setup (void)
 #ifdef __x86_64__
   tdesc = amd64_create_target_description (X86_XSTATE_SSE_MASK, false,
                                                 false);
+  const char **expedite_regs = amd64_expedite_regs;
 #else
   tdesc = i386_create_target_description (X86_XSTATE_SSE_MASK, false);
+  const char **expedite_regs = i386_expedite_regs;
 #endif
 
-  init_target_desc (tdesc);
+  init_target_desc (tdesc, expedite_regs);
 
   win32_tdesc = tdesc;
 }

diff --git a/gdb/gdbserver/x86-tdesc.h b/gdb/gdbserver/x86-tdesc.h
new file mode 100755 (executable)
index 0000000..c1641b2
--- /dev/null
+++ b/gdb/gdbserver/x86-tdesc.h
@@ -0,0 +1,26 @@
+/* Copyright (C) 2018 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#ifndef X86_TDESC_H
+
+/* The "expedite" registers for x86 targets.  */
+static const char *i386_expedite_regs[] = {"ebp", "esp", "eip", NULL};
+
+/* The "expedite" registers for x86_64 targets.  */
+static const char *amd64_expedite_regs[] = {"rbp", "rsp", "rip", NULL};
+
+#endif /* X86_TDESC_H */

diff --git a/gdb/regformats/regdat.sh b/gdb/regformats/regdat.sh
index 8f546fe276961e87d29fcc08000f43def93b7de6..5a8564ac50c0ae69787437d61c740cde2772f996 100755 (executable)
--- a/gdb/regformats/regdat.sh
+++ b/gdb/regformats/regdat.sh
@@ -185,11 +185,10 @@ echo
 
 cat <<EOF
 #ifndef IN_PROCESS_AGENT
-  result->expedite_regs = expedite_regs_${name};
   result->xmltarget = xmltarget_${name};
 #endif
 
-  init_target_desc (result);
+  init_target_desc (result, expedite_regs_${name});
 
   tdesc_${name} = result;
 }