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[PATCH] null ptr check to prevent gdbserver from crashing
- From: Sanimir Agovic <sanimir dot agovic at intel dot com>
- To: gdb-patches at sourceware dot org
- Date: Thu, 20 Dec 2012 10:09:02 +0100
- Subject: [PATCH] null ptr check to prevent gdbserver from crashing
Evaluating a thread local storage variable in a remote scenario crashes
gdbserver if libthread-db could not be loaded.
2012-12-18 Sanimir Agovic <sanimir.agovic@intel.com>
gdbserver/
* thread-db.c (thread_db_get_tls_address):
NULL pointer check thread_db.
testsuite/
* gdb.server/no-thread-db.exp: New file.
* gdb.server/no-thread-db.c: New file.
* gdb.server/Makefile.in (EXECUTABLES): Add no-thread-db.
---
gdb/gdbserver/thread-db.c | 2 +-
gdb/testsuite/gdb.server/Makefile.in | 3 +-
gdb/testsuite/gdb.server/no-thread-db.c | 28 ++++++++++++++++
gdb/testsuite/gdb.server/no-thread-db.exp | 56 +++++++++++++++++++++++++++++++
4 files changed, 87 insertions(+), 2 deletions(-)
create mode 100644 gdb/testsuite/gdb.server/no-thread-db.c
create mode 100644 gdb/testsuite/gdb.server/no-thread-db.exp
diff --git a/gdb/gdbserver/thread-db.c b/gdb/gdbserver/thread-db.c
index 9d2041d..fab8a2c 100644
--- a/gdb/gdbserver/thread-db.c
+++ b/gdb/gdbserver/thread-db.c
@@ -494,7 +494,7 @@ thread_db_get_tls_address (struct thread_info *thread, CORE_ADDR offset,
thread_db = proc->private->thread_db;
/* If the thread layer is not (yet) initialized, fail. */
- if (!thread_db->all_symbols_looked_up)
+ if (thread_db == NULL || !thread_db->all_symbols_looked_up)
return TD_ERR;
if (thread_db->td_thr_tls_get_addr_p == NULL)
diff --git a/gdb/testsuite/gdb.server/Makefile.in b/gdb/testsuite/gdb.server/Makefile.in
index 8d9a867..509fbd8 100644
--- a/gdb/testsuite/gdb.server/Makefile.in
+++ b/gdb/testsuite/gdb.server/Makefile.in
@@ -1,7 +1,8 @@
VPATH = @srcdir@
srcdir = @srcdir@
-EXECUTABLES = ext-attach ext-run file-transfer server-mon server-run
+EXECUTABLES = ext-attach ext-run file-transfer server-mon server-run \
+ no-thread-db
MISCELLANEOUS =
diff --git a/gdb/testsuite/gdb.server/no-thread-db.c b/gdb/testsuite/gdb.server/no-thread-db.c
new file mode 100644
index 0000000..25caabf
--- /dev/null
+++ b/gdb/testsuite/gdb.server/no-thread-db.c
@@ -0,0 +1,28 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012 Free Software Foundation, Inc.
+
+ Contributed by Intel Corporation.
+
+ 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/>. */
+
+__thread int foo;
+
+int
+main ()
+{
+ foo = 1;
+ /* after tls assignment */
+ return foo;
+}
diff --git a/gdb/testsuite/gdb.server/no-thread-db.exp b/gdb/testsuite/gdb.server/no-thread-db.exp
new file mode 100644
index 0000000..48fff6c
--- /dev/null
+++ b/gdb/testsuite/gdb.server/no-thread-db.exp
@@ -0,0 +1,56 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2012 Free Software Foundation, Inc.
+#
+# Contributed by Intel Corporation.
+#
+# 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/>.
+
+# Test gdbserver to handle qGetTLSAddr requests gracefully in case
+# libthread_db could not be loaded.
+
+load_lib gdbserver-support.exp
+
+standard_testfile
+set unresolvable_thread_db_path "/foo/bar"
+
+if {[skip_gdbserver_tests]} {
+ return 0
+}
+
+if {[gdb_compile_pthreads "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+ return -1
+}
+
+clean_restart ${testfile}
+
+# Make sure we're disconnected, in case we're testing with an
+# extended-remote board, therefore already connected.
+gdb_test "disconnect" ".*"
+
+gdbserver_run ""
+
+# Force gdbserver to fail to load libthread_db.
+gdb_test "monitor set libthread-db-search-path ${unresolvable_thread_db_path}" \
+ "libthread-db-search-path set to `${unresolvable_thread_db_path}'" \
+ "libthread-db is now unresolvable"
+
+# Continue past tls assignment to make sure tls storage is allocated.
+gdb_breakpoint [gdb_get_line_number "after tls assignment"]
+gdb_continue_to_breakpoint "after tls assignment"
+
+# Printing a tls variable should fail gracefully without a libthread_db.
+gdb_test "print foo" \
+ "Cannot find thread-local storage for Thread \[^,\]+, executable file ${binfile}:\[\r\n\]+Remote target failed to process qGetTLSAddr request" \
+ "print foo"
--
1.7.11.7