[PATCH 3/4] Optionally allow unknown symbols in the backtrace tests
Ulf Hermann
ulf.hermann@qt.io
Fri Feb 10 14:19:00 GMT 2017
This is useful to test unwinding without debug information. The
binaries being examined might still have frame pointers that allow
us to bridge the unknown symbols.
Signed-off-by: Ulf Hermann <ulf.hermann@qt.io>
---
tests/ChangeLog | 6 ++++++
tests/backtrace-subr.sh | 14 ++++++++++----
tests/backtrace.c | 30 ++++++++++++++++++++++--------
3 files changed, 38 insertions(+), 12 deletions(-)
diff --git a/tests/ChangeLog b/tests/ChangeLog
index 7040ac8..bca47be 100644
--- a/tests/ChangeLog
+++ b/tests/ChangeLog
@@ -1,5 +1,11 @@
2017-02-09 Ulf Hermann <ulf.hermann@qt.io>
+ * backtrace.c: Add an option to allow unknown symbols in the trace
+ * backtrace-substr.sh: Add an option to allow unknown symbols
+ to check_core() and allow failed symbol lookups in check_err()
+
+2017-02-09 Ulf Hermann <ulf.hermann@qt.io>
+
* backtrace-data.c: Don't assert that symbols are found.
The unwinder is allowed to ask for invalid addresses. We deny
such requests, rather than make the test fail.
diff --git a/tests/backtrace-subr.sh b/tests/backtrace-subr.sh
index 790b4f4..5d3937c 100644
--- a/tests/backtrace-subr.sh
+++ b/tests/backtrace-subr.sh
@@ -44,9 +44,12 @@ check_gsignal()
# In some cases we cannot reliably find out we got behind _start as some
# operating system do not properly terminate CFI by undefined PC.
# Ignore it here as it is a bug of OS, not a bug of elfutils.
+# If the CFI is not terminated correctly, we might find another frame by
+# checking for frame pointers. This is still not our problem, but only
+# gives an error message when trying to look up the function name.
check_err()
{
- if [ $(egrep -v <$1 'dwfl_thread_getframes: (No DWARF information found|no matching address range)$' \
+ if [ $(egrep -v <$1 'dwfl_thread_getframes: (No DWARF information found|no matching address range|address out of range)$' \
| wc -c) \
-eq 0 ]
then
@@ -61,7 +64,9 @@ check_all()
bt=$1
err=$2
testname=$3
- check_main $bt $testname
+ if [ "x$4" != "x--allow-unknown" ]; then
+ check_main $bt $testname
+ fi
check_gsignal $bt $testname
check_err $err $testname
}
@@ -98,13 +103,14 @@ check_native_unsupported()
check_core()
{
arch=$1
+ args=$2
testfiles backtrace.$arch.{exec,core}
tempfiles backtrace.$arch.{bt,err}
echo ./backtrace ./backtrace.$arch.{exec,core}
- testrun ${abs_builddir}/backtrace -e ./backtrace.$arch.exec --core=./backtrace.$arch.core 1>backtrace.$arch.bt 2>backtrace.$arch.err || true
+ testrun ${abs_builddir}/backtrace $args -e ./backtrace.$arch.exec --core=./backtrace.$arch.core 1>backtrace.$arch.bt 2>backtrace.$arch.err || true
cat backtrace.$arch.{bt,err}
check_unsupported backtrace.$arch.err backtrace.$arch.core
- check_all backtrace.$arch.{bt,err} backtrace.$arch.core
+ check_all backtrace.$arch.{bt,err} backtrace.$arch.core $args
}
# Backtrace live process.
diff --git a/tests/backtrace.c b/tests/backtrace.c
index 1ff6353..34a2ab0 100644
--- a/tests/backtrace.c
+++ b/tests/backtrace.c
@@ -64,6 +64,7 @@ dump_modules (Dwfl_Module *mod, void **userdata __attribute__ ((unused)),
return DWARF_CB_OK;
}
+static bool allow_unknown;
static bool use_raise_jmp_patching;
static pid_t check_tid;
@@ -78,7 +79,8 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
seen_main = true;
if (pc == 0)
{
- assert (seen_main);
+ if (!allow_unknown)
+ assert (seen_main);
return;
}
if (check_tid == 0)
@@ -103,11 +105,12 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
&& (strcmp (symname, "__kernel_vsyscall") == 0
|| strcmp (symname, "__libc_do_syscall") == 0))
reduce_frameno = true;
- else
+ else if (!allow_unknown || symname)
assert (symname && strcmp (symname, "raise") == 0);
break;
case 1:
- assert (symname != NULL && strcmp (symname, "sigusr2") == 0);
+ if (!allow_unknown || symname)
+ assert (symname != NULL && strcmp (symname, "sigusr2") == 0);
break;
case 2: // x86_64 only
/* __restore_rt - glibc maybe does not have to have this symbol. */
@@ -116,20 +119,24 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
if (use_raise_jmp_patching)
{
/* Verify we trapped on the very first instruction of jmp. */
- assert (symname != NULL && strcmp (symname, "jmp") == 0);
+ if (!allow_unknown || symname)
+ assert (symname != NULL && strcmp (symname, "jmp") == 0);
mod = dwfl_addrmodule (dwfl, pc - 1);
if (mod)
symname2 = dwfl_module_addrname (mod, pc - 1);
- assert (symname2 == NULL || strcmp (symname2, "jmp") != 0);
+ if (!allow_unknown || symname2)
+ assert (symname2 == NULL || strcmp (symname2, "jmp") != 0);
break;
}
/* FALLTHRU */
case 4:
- assert (symname != NULL && strcmp (symname, "stdarg") == 0);
+ if (!allow_unknown || symname)
+ assert (symname != NULL && strcmp (symname, "stdarg") == 0);
break;
case 5:
/* Verify we trapped on the very last instruction of child. */
- assert (symname != NULL && strcmp (symname, "backtracegen") == 0);
+ if (!allow_unknown || symname)
+ assert (symname != NULL && strcmp (symname, "backtracegen") == 0);
mod = dwfl_addrmodule (dwfl, pc);
if (mod)
symname2 = dwfl_module_addrname (mod, pc);
@@ -138,7 +145,7 @@ callback_verify (pid_t tid, unsigned frameno, Dwarf_Addr pc,
// there is no guarantee that the compiler doesn't reorder the
// instructions or even inserts some padding instructions at the end
// (which apparently happens on ppc64).
- if (use_raise_jmp_patching)
+ if (use_raise_jmp_patching && (!allow_unknown || symname2))
assert (symname2 == NULL || strcmp (symname2, "backtracegen") != 0);
break;
}
@@ -424,10 +431,12 @@ exec_dump (const char *exec)
}
#define OPT_BACKTRACE_EXEC 0x100
+#define OPT_ALLOW_UNKNOWN 0x200
static const struct argp_option options[] =
{
{ "backtrace-exec", OPT_BACKTRACE_EXEC, "EXEC", 0, N_("Run executable"), 0 },
+ { "allow-unknown", OPT_ALLOW_UNKNOWN, 0, 0, N_("Allow unknown symbols"), 0 },
{ NULL, 0, NULL, 0, NULL, 0 }
};
@@ -445,6 +454,10 @@ parse_opt (int key, char *arg, struct argp_state *state)
exec_dump (arg);
exit (0);
+ case OPT_ALLOW_UNKNOWN:
+ allow_unknown = true;
+ break;
+
default:
return ARGP_ERR_UNKNOWN;
}
@@ -463,6 +476,7 @@ main (int argc __attribute__ ((unused)), char **argv)
(void) setlocale (LC_ALL, "");
elf_version (EV_CURRENT);
+ allow_unknown = false;
Dwfl *dwfl = NULL;
const struct argp_child argp_children[] =
--
2.1.4
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