From 199e23780a7e75c63a9e3d1108804e3af450ea3e Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Fri, 3 Jul 2009 13:02:39 +0200 Subject: [PATCH] x86: atomic64: Fix unclean type use in atomic64_xchg() Linus noticed that atomic64_xchg() uses atomic_read(), which happens to work because atomic_read() is a macro so the .counter value gets u64-read on 32-bit too - but this is really bogus and serious bugs are waiting to happen. Fix atomic64_xchg() to use __atomic64_read() instead. No code changed: arch/x86/lib/atomic64_32.o: text data bss dec hex filename 435 0 0 435 1b3 atomic64_32.o.before 435 0 0 435 1b3 atomic64_32.o.after md5: bd8ab95e69c93518578bfaf0ea3be4d9 atomic64_32.o.before.asm bd8ab95e69c93518578bfaf0ea3be4d9 atomic64_32.o.after.asm Reported-by: Linus Torvalds Cc: Eric Dumazet Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: David Howells Cc: Andrew Morton Cc: Arnd Bergmann LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/lib/atomic64_32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c index a910238a7760..fd28fd3fb742 100644 --- a/arch/x86/lib/atomic64_32.c +++ b/arch/x86/lib/atomic64_32.c @@ -36,7 +36,7 @@ u64 atomic64_xchg(atomic64_t *ptr, u64 new_val) u64 old_val; do { - old_val = atomic_read(ptr); + old_val = __atomic64_read(ptr); } while (atomic64_cmpxchg(ptr, old_val, new_val) != old_val); return old_val; -- 2.20.1