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authorIngo Molnar <mingo@elte.hu>2009-07-03 13:02:39 +0200
committerIngo Molnar <mingo@elte.hu>2009-07-03 13:26:46 +0200
commit199e23780a7e75c63a9e3d1108804e3af450ea3e (patch)
treed9f117d53df2687f0f207c3ccd77506dfec83e8f /arch
parent3217120873598533234b6dedda9c371ce30001d0 (diff)
downloadop-kernel-dev-199e23780a7e75c63a9e3d1108804e3af450ea3e.zip
op-kernel-dev-199e23780a7e75c63a9e3d1108804e3af450ea3e.tar.gz
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 <torvalds@linux-foundation.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> LKML-Reference: <alpine.LFD.2.01.0907021653030.3210@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/lib/atomic64_32.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c
index a910238..fd28fd3 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;
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