Take a little more care in set_backtrace().

Coverity complained that the "errtrace" string is leaked if we return
early because backtrace_symbols fails.  Another criticism that could
be leveled at this is that not providing any hint of what happened is
user-unfriendly.  Fix that.

The odds of a leak here are small, and typically it wouldn't matter
anyway since the leak will be in ErrorContext which will soon get
reset.  So I'm not feeling a need to back-patch.

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 47af743990fe9a5819d165f73bcead833dda67d6..afce1a8e1f003094425a08aeeb9182f2e29c64fb 100644 (file)
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -1128,12 +1128,15 @@ set_backtrace(ErrorData *edata, int num_skip)
 
        nframes = backtrace(buf, lengthof(buf));
        strfrms = backtrace_symbols(buf, nframes);
-       if (strfrms == NULL)
-           return;
-
-       for (int i = num_skip; i < nframes; i++)
-           appendStringInfo(&errtrace, "\n%s", strfrms[i]);
-       free(strfrms);
+       if (strfrms != NULL)
+       {
+           for (int i = num_skip; i < nframes; i++)
+               appendStringInfo(&errtrace, "\n%s", strfrms[i]);
+           free(strfrms);
+       }
+       else
+           appendStringInfoString(&errtrace,
+                                  "insufficient memory for backtrace generation");
    }
 #else
    appendStringInfoString(&errtrace,