[ovs-dev] backtrace: Replace usage of libunwind with libc backtrace

diff --git a/include/openvswitch/vlog.h b/include/openvswitch/vlog.h
index e53ce6d81..98edc3452 100644
--- a/include/openvswitch/vlog.h
+++ b/include/openvswitch/vlog.h
@@ -145,8 +145,8 @@  void vlog_set_syslog_method(const char *method);
 /* Configure syslog target. */
 void vlog_set_syslog_target(const char *target);
 
-/* Write directly to log file. */
-void vlog_direct_write_to_log_file_unsafe(const char *s);
+/* Return the current vlog file descriptor. */
+int vlog_fd(void);
 
 /* Initialization. */
 void vlog_init(void);
diff --git a/lib/backtrace.c b/lib/backtrace.c
index 2853d5ff1..713b99e7b 100644
--- a/lib/backtrace.c
+++ b/lib/backtrace.c
@@ -32,13 +32,23 @@  VLOG_DEFINE_THIS_MODULE(backtrace);
 void
 backtrace_capture(struct backtrace *b)
 {
-    void *frames[BACKTRACE_MAX_FRAMES];
-    int i;
+    b->n_frames = backtrace(b->frames, BACKTRACE_MAX_FRAMES);
+}
+
+char *
+backtrace_format(const struct backtrace *bt, struct ds *ds)
+{
+    if (bt->n_frames) {
+        char **symbols = backtrace_symbols(bt->frames, bt->n_frames);
 
-    b->n_frames = backtrace(frames, BACKTRACE_MAX_FRAMES);
-    for (i = 0; i < b->n_frames; i++) {
-        b->frames[i] = (uintptr_t) frames[i];
+        for (int i = 0; i < bt->n_frames; i++) {
+            ds_put_format(ds, "%s\n", symbols[i]);
+        }
+
+        free(symbols);
     }
+
+    return ds_cstr(ds);
 }
 
 #else
@@ -47,23 +57,15 @@  backtrace_capture(struct backtrace *backtrace)
 {
     backtrace->n_frames = 0;
 }
-#endif
 
-static char *
-backtrace_format(const struct backtrace *b, struct ds *ds)
+char *
+backtrace_format(const struct backtrace *bt OVS_UNUSED, struct ds *ds)
 {
-    if (b->n_frames) {
-        int i;
-
-        ds_put_cstr(ds, " (backtrace:");
-        for (i = 0; i < b->n_frames; i++) {
-            ds_put_format(ds, " 0x%08"PRIxPTR, b->frames[i]);
-        }
-        ds_put_cstr(ds, ")");
-    }
+    ds_put_cstr(ds, BACKTRACE_UNSUPPORTED_MSG);
 
     return ds_cstr(ds);
 }
+#endif
 
 void
 log_backtrace_at(const char *msg, const char *where)
@@ -77,41 +79,8 @@  log_backtrace_at(const char *msg, const char *where)
     }
 
     ds_put_cstr(&ds, where);
+    ds_put_cstr(&ds, " backtrace:\n");
     VLOG_ERR("%s", backtrace_format(&b, &ds));
 
     ds_destroy(&ds);
 }
-
-#ifdef HAVE_UNWIND
-void
-log_received_backtrace(int fd) {
-    int byte_read;
-    struct unw_backtrace backtrace[UNW_MAX_DEPTH];
-
-    VLOG_WARN("%s fd %d", __func__, fd);
-    fcntl(fd, F_SETFL, O_NONBLOCK);
-    memset(backtrace, 0, UNW_MAX_BUF);
-
-    byte_read = read(fd, backtrace, UNW_MAX_BUF);
-    if (byte_read < 0) {
-        VLOG_ERR("Read fd %d failed: %s", fd,
-                 ovs_strerror(errno));
-    } else if (byte_read > 0) {
-        VLOG_WARN("SIGSEGV detected, backtrace:");
-        for (int i = 0; i < UNW_MAX_DEPTH; i++) {
-            if (backtrace[i].func[0] == 0) {
-                break;
-            }
-            VLOG_WARN("0x%016"PRIxPTR" <%s+0x%"PRIxPTR">\n",
-                      backtrace[i].ip,
-                      backtrace[i].func,
-                      backtrace[i].offset);
-        }
-    }
-}
-#else /* !HAVE_UNWIND */
-void
-log_received_backtrace(int daemonize_fd OVS_UNUSED) {
-    VLOG_WARN("Backtrace using libunwind not supported.");
-}
-#endif /* HAVE_UNWIND */
diff --git a/lib/backtrace.h b/lib/backtrace.h
index 5708bf9c6..55b25dca0 100644
--- a/lib/backtrace.h
+++ b/lib/backtrace.h
@@ -20,11 +20,6 @@ 
 #include <stdint.h>
 #include "openvswitch/dynamic-string.h"
 
-#ifdef HAVE_UNWIND
-#define UNW_LOCAL_ONLY
-#include <libunwind.h>
-#endif
-
 /* log_backtrace() will save the backtrace of a running program
  * into the log at the DEBUG level.
  *
@@ -36,58 +31,57 @@ 
  *       log_backtrace_msg("your message");         <-- with a message
  *
  *
- * A typical log will look like the following. The hex numbers listed after
- * "backtrace" are the addresses of the backtrace.
+ * A typical backtrace will look like the following example:
+ * /lib64/libopenvswitch-3.1.so.0(backtrace_capture+0x1e) [0x7fc5db298dfe]
+ * /lib64/libopenvswitch-3.1.so.0(log_backtrace_at+0x57) [0x7fc5db2999e7]
+ * /lib64/libovsdb-3.1.so.0(ovsdb_txn_complete+0x7b) [0x7fc5db56247b]
+ * /lib64/libovsdb-3.1.so.0(ovsdb_txn_propose_commit_block+0x8d) [0x7fc5db563a8d]
+ * ovsdb-server(+0xa661) [0x562cfce2e661]
+ * ovsdb-server(+0x7e39) [0x562cfce2be39]
+ * /lib64/libc.so.6(+0x27b4a) [0x7fc5db048b4a]
+ * /lib64/libc.so.6(__libc_start_main+0x8b) [0x7fc5db048c0b]
+ * ovsdb-server(+0x8c35) [0x562cfce2cc35]
  *
- * 2014-03-13T23:18:11.979Z|00002|backtrace(revalidator_6)|ERR|lib/dpif-netdev.c:1312: (backtrace: 0x00521f57 0x00460365 0x00463ea4 0x0046470b 0x0043b32d 0x0043bac3 0x0043bae2 0x0043943b 0x004c22b3 0x2b5b3ac94e9a 0x2b5b3b4a33fd)
+ * GDB can be used to view the exact line of the code for particular backtrace.
+ * One thing to keep in mind is that the lines in source files might not
+ * 100% correspond with the backtrace due to various optimizations as LTO etc.
+ * (The effect can be seen in this example).
  *
- * The following bash command can be used to  view backtrace in
- * a more readable form.
- * addr2line -p -e vswitchd/ovs-vswitchd <cut-and-paste back traces>
+ * Assuming that debuginfo for the library or binary is installed load it to
+ * GDB:
+ * $ gdb ovsdb-server
+ * (gdb) list *(+0x7e39)
+ * 0x7e39 is in main (ovsdb/ovsdb-server.c:278).
+ * (gdb) list *(+0xa661)
+ * 0xa661 is in commit_txn (ovsdb/ovsdb-server.c:1173)
  *
- * An typical run and output will look like:
- * addr2line -p -e vswitchd/ovs-vswitchd  0x00521f57 0x00460365 0x00463ea4
- * 0x0046470b 0x0043b32d 0x0043bac3 0x0043bae2 0x0043943b 0x004c22b3
- * 0x2b5b3ac94e9a 0x2b5b3b4a33fd
+ * $ gdb /lib64/libovsdb-3.1.so.0
+ * (gdb) list *(ovsdb_txn_propose_commit_block+0x8d)
+ * 0x3aa8d is in ovsdb_txn_propose_commit_block (ovsdb/transaction.c:1328)
+ * (gdb) list *(ovsdb_txn_complete+0x7b)
+ * 0x3947b is in ovsdb_txn_complete (./include/openvswitch/list.h:321)
  *
- * openvswitch/lib/backtrace.c:33
- * openvswitch/lib/dpif-netdev.c:1312
- * openvswitch/lib/dpif.c:937
- * openvswitch/lib/dpif.c:1258
- * openvswitch/ofproto/ofproto-dpif-upcall.c:1440
- * openvswitch/ofproto/ofproto-dpif-upcall.c:1595
- * openvswitch/ofproto/ofproto-dpif-upcall.c:160
- * openvswitch/ofproto/ofproto-dpif-upcall.c:717
- * openvswitch/lib/ovs-thread.c:268
- * ??:0
- * ??:0
+ * $ gdb /lib64/libopenvswitch-3.1.so.0
+ * (gdb) list *(log_backtrace_at+0x57)
+ * 0x999e7 is in log_backtrace_at (lib/backtrace.c:77)
+ * (gdb) list *(backtrace_capture+0x1e)
+ * 0x98dfe is in backtrace_capture (lib/backtrace.c:35)
  */
 
 #define log_backtrace() log_backtrace_at(NULL, OVS_SOURCE_LOCATOR);
 #define log_backtrace_msg(msg) log_backtrace_at(msg, OVS_SOURCE_LOCATOR);
 
 #define BACKTRACE_MAX_FRAMES 31
+#define BACKTRACE_DUMP_MSG "SIGSEGV detected, backtrace:\n"
+#define BACKTRACE_UNSUPPORTED_MSG "backtrace() is not supported!\n"
 
 struct backtrace {
     int n_frames;
-    uintptr_t frames[BACKTRACE_MAX_FRAMES];
-};
-
-#ifdef HAVE_UNWIND
-#define UNW_MAX_DEPTH 32
-#define UNW_MAX_FUNCN 32
-#define UNW_MAX_BUF \
-    (UNW_MAX_DEPTH * sizeof(struct unw_backtrace))
-
-struct unw_backtrace {
-    char func[UNW_MAX_FUNCN];
-    unw_word_t ip;
-    unw_word_t offset;
+    void *frames[BACKTRACE_MAX_FRAMES];
 };
-#endif
 
 void backtrace_capture(struct backtrace *);
 void log_backtrace_at(const char *msg, const char *where);
-void log_received_backtrace(int fd);
+char *backtrace_format(const struct backtrace *bt, struct ds *ds);
 
 #endif /* backtrace.h */
diff --git a/lib/daemon-unix.c b/lib/daemon-unix.c
index 1a7ba427d..68706f73a 100644
--- a/lib/daemon-unix.c
+++ b/lib/daemon-unix.c
@@ -395,7 +395,6 @@  monitor_daemon(pid_t daemon_pid)
                     }
                 }
 
-                log_received_backtrace(daemonize_fd);
                 close(daemonize_fd);
                 daemonize_fd = -1;
 
diff --git a/lib/fatal-signal.c b/lib/fatal-signal.c
index bbb31ef27..b822fc774 100644
--- a/lib/fatal-signal.c
+++ b/lib/fatal-signal.c
@@ -35,8 +35,8 @@ 
 
 #include "openvswitch/type-props.h"
 
-#ifdef HAVE_UNWIND
-#include "daemon-private.h"
+#ifdef HAVE_BACKTRACE
+#include <execinfo.h>
 #endif
 
 #ifndef SIG_ATOMIC_MAX
@@ -94,6 +94,13 @@  fatal_signal_init(void)
         inited = true;
 
         ovs_mutex_init_recursive(&mutex);
+
+        /* The dummy backtrace is needed see comment for
+         * send_backtrace_to_monitor(). */
+        struct backtrace dummy_bt;
+        backtrace_capture(&dummy_bt);
+        VLOG_DBG("Load \"libgcc\" by capturing dummy backtrace, n_frames=%d",
+                 dummy_bt.n_frames);
 #ifndef _WIN32
         xpipe_nonblocking(signal_fds);
 #else
@@ -157,94 +164,33 @@  fatal_signal_add_hook(void (*hook_cb)(void *aux), void (*cancel_cb)(void *aux),
     ovs_mutex_unlock(&mutex);
 }
 
-#ifdef HAVE_UNWIND
-/* Convert unsigned long long to string.  This is needed because
- * using snprintf() is not async signal safe. */
-static inline int
-llong_to_hex_str(unsigned long long value, char *str)
-{
-    int i = 0, res;
-
-    if (value / 16 > 0) {
-        i = llong_to_hex_str(value / 16, str);
-    }
-
-    res = value % 16;
-    str[i] = "0123456789abcdef"[res];
-
-    return i + 1;
-}
-
 /* Send the backtrace buffer to monitor thread.
  *
  * Note that this runs in the signal handling context, any system
  * library functions used here must be async-signal-safe.
+ * backtrace() is only signal safe if the "libgcc" was loaded
+ * before the signal handler. In order to keep it safe the fatal_signal_init()
+ * should always call backtrace_capture which will ensure that "libgcc" is
+ * loaded.
  */
 static inline void
 send_backtrace_to_monitor(void) {
-    /* volatile added to prevent a "clobbered" error on ppc64le with gcc */
-    volatile int dep;
-    struct unw_backtrace unw_bt[UNW_MAX_DEPTH];
-    unw_cursor_t cursor;
-    unw_context_t uc;
-
-    if (daemonize_fd == -1) {
+    int log_fd = vlog_fd();
+    if (!log_fd) {
         return;
     }
 
-    dep = 0;
-    unw_getcontext(&uc);
-    unw_init_local(&cursor, &uc);
+    struct backtrace bt;
+    backtrace_capture(&bt);
 
-    while (dep < UNW_MAX_DEPTH && unw_step(&cursor)) {
-        memset(unw_bt[dep].func, 0, UNW_MAX_FUNCN);
-        unw_get_reg(&cursor, UNW_REG_IP, &unw_bt[dep].ip);
-        unw_get_proc_name(&cursor, unw_bt[dep].func, UNW_MAX_FUNCN,
-                          &unw_bt[dep].offset);
-        dep++;
-    }
-
-    if (monitor) {
-        ignore(write(daemonize_fd, unw_bt,
-                     dep * sizeof(struct unw_backtrace)));
-    } else {
-        /* Since there is no monitor daemon running, write backtrace
-         * in current process.
-         */
-        char str[] = "SIGSEGV detected, backtrace:\n";
-        char ip_str[16], offset_str[6];
-        char line[64], fn_name[UNW_MAX_FUNCN];
-
-        vlog_direct_write_to_log_file_unsafe(str);
-
-        for (int i = 0; i < dep; i++) {
-            memset(line, 0, sizeof line);
-            memset(fn_name, 0, sizeof fn_name);
-            memset(offset_str, 0, sizeof offset_str);
-            memset(ip_str, ' ', sizeof ip_str);
-            ip_str[sizeof(ip_str) - 1] = 0;
-
-            llong_to_hex_str(unw_bt[i].ip, ip_str);
-            llong_to_hex_str(unw_bt[i].offset, offset_str);
-
-            strcat(line, "0x");
-            strcat(line, ip_str);
-            strcat(line, "<");
-            memcpy(fn_name, unw_bt[i].func, UNW_MAX_FUNCN - 1);
-            strcat(line, fn_name);
-            strcat(line, "+0x");
-            strcat(line, offset_str);
-            strcat(line, ">\n");
-            vlog_direct_write_to_log_file_unsafe(line);
-        }
-    }
-}
+    ignore(write(log_fd, BACKTRACE_DUMP_MSG, strlen(BACKTRACE_DUMP_MSG)));
+#ifdef HAVE_BACKTRACE
+    backtrace_symbols_fd(bt.frames, bt.n_frames, log_fd);
 #else
-static inline void
-send_backtrace_to_monitor(void) {
-    /* Nothing. */
-}
+    ignore(write(log_fd, BACKTRACE_UNSUPPORTED_MSG,
+                 strlen(BACKTRACE_UNSUPPORTED_MSG)));
 #endif
+}
 
 /* Handles fatal signal number 'sig_nr'.
  *
diff --git a/lib/ovsdb-error.c b/lib/ovsdb-error.c
index a75ad36b7..2cd6242f3 100644
--- a/lib/ovsdb-error.c
+++ b/lib/ovsdb-error.c
@@ -139,17 +139,6 @@  ovsdb_internal_error(struct ovsdb_error *inner_error,
         va_end(args);
     }
 
-    backtrace_capture(&backtrace);
-    if (backtrace.n_frames) {
-        int i;
-
-        ds_put_cstr(&ds, " (backtrace:");
-        for (i = 0; i < backtrace.n_frames; i++) {
-            ds_put_format(&ds, " 0x%08"PRIxPTR, backtrace.frames[i]);
-        }
-        ds_put_char(&ds, ')');
-    }
-
     ds_put_format(&ds, " (%s %s)", program_name, VERSION);
 
     if (inner_error) {
@@ -158,6 +147,10 @@  ovsdb_internal_error(struct ovsdb_error *inner_error,
         free(s);
     }
 
+    ds_put_cstr(&ds, ", backtrace:");
+    backtrace_capture(&backtrace);
+    backtrace_format(&backtrace, &ds);
+
     error = ovsdb_error("internal error", "%s", ds_cstr(&ds));
 
     ds_destroy(&ds);
diff --git a/lib/vlog.c b/lib/vlog.c
index 9ddea48b8..b40c6909d 100644
--- a/lib/vlog.c
+++ b/lib/vlog.c
@@ -649,19 +649,11 @@  vlog_set_syslog_target(const char *target)
     ovs_rwlock_unlock(&pattern_rwlock);
 }
 
-/*
- * This function writes directly to log file without using async writer or
- * taking a lock.  Caller must hold 'log_file_mutex' or be sure that it's
- * not necessary.  Could be used in exceptional cases like dumping of backtrace
- * on fatal signals.
- */
-void
-vlog_direct_write_to_log_file_unsafe(const char *s)
+int
+vlog_fd(void)
     OVS_NO_THREAD_SAFETY_ANALYSIS
 {
-    if (log_fd >= 0) {
-        ignore(write(log_fd, s, strlen(s)));
-    }
+    return log_fd;
 }
 
 /* Returns 'false' if 'facility' is not a valid string. If 'facility'
diff --git a/m4/openvswitch.m4 b/m4/openvswitch.m4
index 14d9249b8..64a097d90 100644
--- a/m4/openvswitch.m4
+++ b/m4/openvswitch.m4
@@ -359,9 +359,12 @@  AC_DEFUN([OVS_CHECK_DBDIR],
 
 dnl Defines HAVE_BACKTRACE if backtrace() is found.
 AC_DEFUN([OVS_CHECK_BACKTRACE],
-  [AC_SEARCH_LIBS([backtrace], [execinfo ubacktrace],
-                  [AC_DEFINE([HAVE_BACKTRACE], [1],
-                             [Define to 1 if you have backtrace(3).])])])
+  [AC_SEARCH_LIBS([backtrace], [execinfo ubacktrace], [HAVE_BACKTRACE=yes], [HAVE_BACKTRACE=no])
+   if test "$HAVE_BACKTRACE" = "yes"; then
+     AC_DEFINE([HAVE_BACKTRACE], [1], [Define to 1 if you have backtrace(3).])
+   fi
+   AM_CONDITIONAL([HAVE_BACKTRACE], [test "$HAVE_BACKTRACE" = "yes"])
+   AC_SUBST([HAVE_BACKTRACE])])
 
 dnl Defines HAVE_PERF_EVENT if linux/perf_event.h is found.
 AC_DEFUN([OVS_CHECK_PERF_EVENT],
@@ -738,14 +741,3 @@  AC_DEFUN([OVS_CHECK_UNBOUND],
    AM_CONDITIONAL([HAVE_UNBOUND], [test "$HAVE_UNBOUND" = yes])
    AC_SUBST([HAVE_UNBOUND])])
 
-dnl Checks for libunwind.
-AC_DEFUN([OVS_CHECK_UNWIND],
-  [AC_CHECK_LIB([unwind], [unw_backtrace],
-   [AC_CHECK_HEADERS([libunwind.h], [HAVE_UNWIND=yes], [HAVE_UNWIND=no])],
-   [HAVE_UNWIND=no])
-   if test "$HAVE_UNWIND" = yes; then
-     AC_DEFINE([HAVE_UNWIND], [1], [Define to 1 if unwind is detected.])
-     LIBS="$LIBS -lunwind"
-   fi
-   AM_CONDITIONAL([HAVE_UNWIND], [test "$HAVE_UNWIND" = yes])
-   AC_SUBST([HAVE_UNWIND])])
diff --git a/tests/atlocal.in b/tests/atlocal.in
index 859668586..83f9f865c 100644
--- a/tests/atlocal.in
+++ b/tests/atlocal.in
@@ -2,6 +2,7 @@ 
 HAVE_OPENSSL='@HAVE_OPENSSL@'
 OPENSSL_SUPPORTS_SNI='@OPENSSL_SUPPORTS_SNI@'
 HAVE_UNBOUND='@HAVE_UNBOUND@'
+HAVE_BACKTRACE='@HAVE_BACKTRACE@'
 EGREP='@EGREP@'
 PYTHON3='@PYTHON3@'
 CFLAGS='@CFLAGS@'
diff --git a/tests/daemon.at b/tests/daemon.at
index d7981f9d2..b92b45744 100644
--- a/tests/daemon.at
+++ b/tests/daemon.at
@@ -234,3 +234,74 @@  OVS_WAIT_UNTIL([sc query ovsdb-server | grep STATE | grep STOPPED > /dev/null 2>
 AT_CHECK([sc delete ovsdb-server], [0], [[[SC]] DeleteService SUCCESS
 ])
 AT_CLEANUP
+
+
+AT_SETUP([backtrace --detach])
+AT_SKIP_IF([test "$HAVE_BACKTRACE" = "no"])
+
+# This test intentionally causes SIGSEGV, so make Address Sanitizer ignore it.
+ASAN_OPTIONS=$ASAN_OPTIONS:handle_segv=0; export ASAN_OPTIONS
+
+# Skip it if UB Sanitizer is being used.  There's no way to disable the
+# SEGV check at runtime.
+AT_SKIP_IF([test $TESTS_WITH_UBSAN = yes])
+
+# Start the daemon and make sure that the pidfile exists immediately.
+# We don't wait for the pidfile to get created because the daemon is
+# supposed to do so before the parent exits.
+AT_CHECK([ovsdb-server --detach --no-chdir --pidfile --no-db --log-file=`pwd`/ovsdb-server.log --verbose=DBG], [0], [ignore], [ignore])
+
+AT_CHECK([test -s ovsdb-server.pid])
+child=$(cat ovsdb-server.pid)
+
+OVS_WAIT_WHILE([kill -SEGV $child])
+OVS_WAIT_UNTIL([grep -q "^SIGSEGV detected, backtrace:" ovsdb-server.log])
+AT_CHECK([grep -q "fatal_signal|DBG|Load \"libgcc\" by capturing dummy backtrace" ovsdb-server.log])
+
+AT_CLEANUP
+
+AT_SETUP([backtrace --detach --monitor])
+AT_SKIP_IF([test "$HAVE_BACKTRACE" = "no"])
+
+# This test intentionally causes SIGSEGV, so make Address Sanitizer ignore it.
+ASAN_OPTIONS=$ASAN_OPTIONS:handle_segv=0; export ASAN_OPTIONS
+
+# Skip it if UB Sanitizer is being used.  There's no way to disable the
+# SEGV check at runtime.
+AT_SKIP_IF([test $TESTS_WITH_UBSAN = yes])
+
+on_exit 'kill $(cat *.pid)'
+
+# Start the daemon and make sure that the pidfile exists immediately.
+# We don't wait for the pidfile to get created because the daemon is
+# supposed to do so before the parent exits.
+AT_CHECK([ovsdb-server --detach --monitor --no-chdir --pidfile --no-db --log-file=`pwd`/ovsdb-server.log --verbose=DBG], [0], [ignore], [ignore])
+AT_CHECK([test -s ovsdb-server.pid])
+child=$(cat ovsdb-server.pid)
+
+# Check process naming and ancestry.
+monitor=$(parent_pid $child)
+check_process_name $child ovsdb-server
+check_ancestors $child $monitor 1
+
+# Kill the daemon process, making it look like a segfault,
+# and wait for a new daemon process to get spawned.
+AT_CHECK([kill -SEGV $child], [0])
+OVS_WAIT_WHILE([kill -0 $child])
+OVS_WAIT_UNTIL([test -s ovsdb-server.pid && test `cat ovsdb-server.pid` != $child])
+child2=$(cat ovsdb-server.pid)
+
+# Check process naming and ancestry.
+check_process_name $child2 ovsdb-server
+check_ancestors $child2 $monitor 1
+
+# Kill the daemon process with SIGTERM, and wait for the daemon
+# and the monitor processes to go away and the pidfile to get deleted.
+AT_CHECK([kill $child2])
+OVS_WAIT_WHILE([kill -0 $monitor || kill -0 $child2 || test -e ovsdb-server.pid])
+
+AT_CHECK([grep -q "fatal_signal|DBG|Load \"libgcc\" by capturing dummy backtrace" ovsdb-server.log])
+AT_CHECK([grep -q "^SIGSEGV detected, backtrace:" ovsdb-server.log])
+AT_CHECK([grep -q "daemon_unix(monitor)|ERR|1 crashes: pid .* died, killed (Segmentation fault), core dumped, restarting" ovsdb-server.log])
+
+AT_CLEANUP