liblockdep: Fix undefined symbol prandom_u32

__lock_pin_lock() now calls prandom_u32() which is not defined in
liblockdep.  __lock_pin_lock() and its caller lock_pin_lock() are dead
code in liblockdep, but we still need to provide a definition of
prandom_u32() in case lazy binding is disabled.

Fixes: e7904a28f533 ("locking/lockdep, sched/core: Implement a better ...")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name liblockdep-fix-undefined-symbol-prandom_u32.patch

diff --git a/tools/lib/lockdep/lockdep.c b/tools/lib/lockdep/lockdep.c
index a0a2e3a266af8122fed3d66b3f5a537ab3c1c773..443acb11f907352887c90cd07389da4be836c418 100644 (file)
--- a/tools/lib/lockdep/lockdep.c
+++ b/tools/lib/lockdep/lockdep.c
@@ -1,8 +1,15 @@
 #include <linux/lockdep.h>
+#include <stdlib.h>
 
 /* Trivial API wrappers, we don't (yet) have RCU in user-space: */
 #define hlist_for_each_entry_rcu       hlist_for_each_entry
 #define hlist_add_head_rcu             hlist_add_head
 #define hlist_del_rcu                  hlist_del
 
+u32 prandom_u32(void)
+{
+       /* Used only by lock_pin_lock() which is dead code */
+       abort();
+}
+
 #include "../../../kernel/locking/lockdep.c"