From 3771b0fe9dfc3801eac0142d1af6ba94dee83c6c Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 25 Mar 2019 13:57:57 +0100 Subject: locking/lockdep: Avoid bogus Clang warning When lockdep is enabled, and -Wuninitialized warnings are enabled, Clang produces a silly warning for every file we compile: In file included from kernel/sched/fair.c:23: kernel/sched/sched.h:1094:15: error: variable 'cookie' is uninitialized when used here [-Werror,-Wuninitialized] rf->cookie = lockdep_pin_lock(&rq->lock); ^~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/lockdep.h:474:60: note: expanded from macro 'lockdep_pin_lock' #define lockdep_pin_lock(l) ({ struct pin_cookie cookie; cookie; }) ^~~~~~ kernel/sched/sched.h:1094:15: note: variable 'cookie' is declared here include/linux/lockdep.h:474:34: note: expanded from macro 'lockdep_pin_lock' #define lockdep_pin_lock(l) ({ struct pin_cookie cookie; cookie; }) ^ As the 'struct pin_cookie' structure is empty in this configuration, there is no need to initialize it for correctness, but it also does not hurt to set it to an empty structure, so do that to avoid the warning. Signed-off-by: Arnd Bergmann Acked-by: Will Deacon Cc: Bart Van Assche Cc: Joel Fernandes (Google) Cc: Linus Torvalds Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Steven Rostedt (VMware) Cc: Thomas Gleixner Cc: Waiman Long Cc: clang-built-linux@googlegroups.com Link: http://lkml.kernel.org/r/20190325125807.1437049-1-arnd@arndb.de Signed-off-by: Ingo Molnar --- include/linux/lockdep.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/lockdep.h') diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 79c3873d58ac..21725a91442b 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -471,7 +471,7 @@ struct pin_cookie { }; #define NIL_COOKIE (struct pin_cookie){ } -#define lockdep_pin_lock(l) ({ struct pin_cookie cookie; cookie; }) +#define lockdep_pin_lock(l) ({ struct pin_cookie cookie = { }; cookie; }) #define lockdep_repin_lock(l, c) do { (void)(l); (void)(c); } while (0) #define lockdep_unpin_lock(l, c) do { (void)(l); (void)(c); } while (0) -- cgit v1.2.3-59-g8ed1b