kdb: Fix handling of kallsyms_symbol_next() return value

kallsyms_symbol_next() returns a boolean (true on success). Currently
kdb_read() tests the return value with an inequality that
unconditionally evaluates to true.

This is fixed in the obvious way and, since the conditional branch is
supposed to be unreachable, we also add a WARN_ON().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index e74be38245adf732f34c55c0a676004f59870ba4..ed5d34925ad0617a40aeed3774b0e393aec03e99 100644 (file)
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -350,7 +350,7 @@ poll_again:
                        }
                        kdb_printf("\n");
                        for (i = 0; i < count; i++) {
-                               if (kallsyms_symbol_next(p_tmp, i) < 0)
+                               if (WARN_ON(!kallsyms_symbol_next(p_tmp, i)))
                                        break;
                                kdb_printf("%s ", p_tmp);
                                *(p_tmp + len) = '\0';