* [PATCH] btrace: do not return out of TRY/CATCH
@ 2015-12-23 14:30 Markus Metzger
2015-12-23 15:06 ` Joel Brobecker
0 siblings, 1 reply; 2+ messages in thread
From: Markus Metzger @ 2015-12-23 14:30 UTC (permalink / raw)
To: palves; +Cc: gdb-patches
In btrace_pt_readmem_callback, we read memory inside TRY/CATCH and return in
case of an error return value. This corrupts the cleanup chain, which
eventually results in a SEGV when doing or discarding cleanups later on.
2015-12-23 Markus Metzger <markus.t.metzger@intel.com>
gdb/
* btrace.c (btrace_pt_readmem_callback): Do not return in TRY/CATCH.
testsuite/
* gdb.btrace/dlopen.exp: New.
* gdb.btrace/dlopen.c: New.
* gdb.btrace/dlopen-dso.c: New.
---
gdb/btrace.c | 9 +++---
gdb/testsuite/gdb.btrace/dlopen-dso.c | 22 +++++++++++++++
gdb/testsuite/gdb.btrace/dlopen.c | 50 +++++++++++++++++++++++++++++++++
gdb/testsuite/gdb.btrace/dlopen.exp | 52 +++++++++++++++++++++++++++++++++++
4 files changed, 129 insertions(+), 4 deletions(-)
create mode 100644 gdb/testsuite/gdb.btrace/dlopen-dso.c
create mode 100644 gdb/testsuite/gdb.btrace/dlopen.c
create mode 100644 gdb/testsuite/gdb.btrace/dlopen.exp
diff --git a/gdb/btrace.c b/gdb/btrace.c
index 35431cb..152daa7 100644
--- a/gdb/btrace.c
+++ b/gdb/btrace.c
@@ -842,21 +842,22 @@ btrace_pt_readmem_callback (gdb_byte *buffer, size_t size,
const struct pt_asid *asid, uint64_t pc,
void *context)
{
- int errcode;
+ int result, errcode;
+ result = (int) size;
TRY
{
errcode = target_read_code ((CORE_ADDR) pc, buffer, size);
if (errcode != 0)
- return -pte_nomap;
+ result = -pte_nomap;
}
CATCH (error, RETURN_MASK_ERROR)
{
- return -pte_nomap;
+ result = -pte_nomap;
}
END_CATCH
- return size;
+ return result;
}
/* Translate the vendor from one enum to another. */
diff --git a/gdb/testsuite/gdb.btrace/dlopen-dso.c b/gdb/testsuite/gdb.btrace/dlopen-dso.c
new file mode 100644
index 0000000..1ea7657
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/dlopen-dso.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ 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/>. */
+
+int
+answer (void)
+{
+ return 42;
+}
diff --git a/gdb/testsuite/gdb.btrace/dlopen.c b/gdb/testsuite/gdb.btrace/dlopen.c
new file mode 100644
index 0000000..70df604
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/dlopen.c
@@ -0,0 +1,50 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2015 Free Software Foundation, Inc.
+
+ 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/>. */
+
+#include <dlfcn.h>
+#include <assert.h>
+#include <stdlib.h>
+
+static int
+test (void)
+{
+ void *dso;
+ int (*fun) (void);
+ int answer;
+
+ dso = dlopen (DSO_NAME, RTLD_NOW | RTLD_GLOBAL);
+ assert (dso != NULL);
+
+ fun = (int (*) (void)) dlsym (dso, "answer");
+ assert (fun != NULL);
+
+ answer = fun ();
+
+ dlclose (dso);
+
+ return answer;
+}
+
+int
+main (void)
+{
+ int answer;
+
+ answer = test ();
+
+ return answer;
+}
diff --git a/gdb/testsuite/gdb.btrace/dlopen.exp b/gdb/testsuite/gdb.btrace/dlopen.exp
new file mode 100644
index 0000000..48368ae
--- /dev/null
+++ b/gdb/testsuite/gdb.btrace/dlopen.exp
@@ -0,0 +1,52 @@
+# This testcase is part of GDB, the GNU debugger.
+#
+# Copyright 2015 Free Software Foundation, Inc.
+#
+# 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/>.
+
+if { [skip_btrace_tests] } { return -1 }
+if { [skip_shlib_tests] } { return -1 }
+
+standard_testfile
+
+set basename_lib dlopen-dso
+set srcfile_lib $srcdir/$subdir/$basename_lib.c
+set binfile_lib [standard_output_file $basename_lib.so]
+
+if { [gdb_compile_shlib $srcfile_lib $binfile_lib \
+ [list additional_flags=-fPIC]] != "" } {
+ untested "Could not compile $binfile_lib."
+ return -1
+}
+
+if { [prepare_for_testing $testfile.exp $testfile $srcfile \
+ [list additional_flags=-DDSO_NAME=\"$binfile_lib\" libs=-ldl]] } {
+ return -1
+}
+
+if ![runto_main] {
+ return 0
+}
+
+# Trace the test function
+#
+gdb_test_no_output "record btrace"
+gdb_test "next"
+
+# The memory containing the library call we traced is already gone.
+# Trace decode used to run into a SEGV after corrupting the cleanup chain.
+#
+# The test passes if we don't crash GDB.
+#
+gdb_test "info record"
--
1.8.3.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] btrace: do not return out of TRY/CATCH
2015-12-23 14:30 [PATCH] btrace: do not return out of TRY/CATCH Markus Metzger
@ 2015-12-23 15:06 ` Joel Brobecker
0 siblings, 0 replies; 2+ messages in thread
From: Joel Brobecker @ 2015-12-23 15:06 UTC (permalink / raw)
To: Markus Metzger; +Cc: palves, gdb-patches
> 2015-12-23 Markus Metzger <markus.t.metzger@intel.com>
>
> gdb/
> * btrace.c (btrace_pt_readmem_callback): Do not return in TRY/CATCH.
>
> testsuite/
> * gdb.btrace/dlopen.exp: New.
> * gdb.btrace/dlopen.c: New.
> * gdb.btrace/dlopen-dso.c: New.
Looks good to me (and I verified that the TRY/CATCH documentation
mentions that we should not goto or return out of it).
Thanks!
--
Joel
^ permalink raw reply [flat|nested] 2+ messages in thread
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