tools/lib/lockdep: 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. Signed-off-by: Ben Hutchings <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Fixes: e7904a2 ("locking/lockdep, sched/core: Implement a better ...") Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
jimmycarry · Jun 5, 2017 · 3752466 · 3752466
1 parent 3c2993b
commit 3752466
Showing 1 changed file with 7 additions and 0 deletions.
diff --git 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"