Messages in this thread Patch in this message |  | | | Date | Fri, 3 Jul 2009 12:44:06 GMT | | From | tip-bot for Ingo Molnar <> | | Subject | [tip:perfcounters/urgent] x86: atomic64: Fix unclean type use in atomic64_xchg() |
Commit-ID: 199e23780a7e75c63a9e3d1108804e3af450ea3e Gitweb: http://git.kernel.org/tip/199e23780a7e75c63a9e3d1108804e3af450ea3e Author: Ingo Molnar <mingo@elte.hu> AuthorDate: Fri, 3 Jul 2009 13:02:39 +0200 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Fri, 3 Jul 2009 13:26:46 +0200
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>
--- arch/x86/lib/atomic64_32.c | 2 +- 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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