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| author | Ingo Molnar <mingo@elte.hu> | 2009-07-03 13:06:01 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-03 13:26:45 +0200 |
| commit | 3217120873598533234b6dedda9c371ce30001d0 (patch) | |
| tree | 3aed0bb4a98bbe2553d9216fa6c965be86e3d8fb /arch | |
| parent | 3ac805d2afd3fa4a07cb5bcf352fd7fa83f28935 (diff) | |
| download | linux-stable-3217120873598533234b6dedda9c371ce30001d0.tar.gz linux-stable-3217120873598533234b6dedda9c371ce30001d0.tar.bz2 linux-stable-3217120873598533234b6dedda9c371ce30001d0.zip | |
x86: atomic64: Make atomic_read() type-safe
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.
Change atomic_read() to be a type-safe inline, and this exposes
the atomic64 bogosity as well:
arch/x86/lib/atomic64_32.c: In function ‘atomic64_xchg’:
arch/x86/lib/atomic64_32.c:39: warning: passing argument 1 of ‘atomic_read’ from incompatible pointer type
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/include/asm/atomic_32.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/include/asm/atomic_32.h b/arch/x86/include/asm/atomic_32.h index 311a43e47c0b..b551bb1ae3cf 100644 --- a/arch/x86/include/asm/atomic_32.h +++ b/arch/x86/include/asm/atomic_32.h @@ -19,7 +19,10 @@ * * Atomically reads the value of @v. */ -#define atomic_read(v) ((v)->counter) +static inline int atomic_read(const atomic_t *v) +{ + return v->counter; +} /** * atomic_set - set atomic variable |