| Date | Tue, 24 Aug 2010 15:45:03 -0700 | From | Greg KH <> | Subject | [058/114] sparc64: Fix rwsem constant bug leading to hangs. |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: David S. Miller <davem@davemloft.net>
[ Upstream commit ef201bebe5afc91a2b99b45dacc8c6dd88ca9e58 ]
As noticed by Linus, it is critical that some of the rwsem constants be signed. Yet, hex constants are unsigned unless explicitly casted or negated.
The most critical one is RWSEM_WAITING_BIAS.
This bug was exacerbated by commit 424acaaeb3a3932d64a9b4bd59df6cf72c22d8f3 ("rwsem: wake queued readers when writer blocks on active read lock")
Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- arch/sparc/include/asm/rwsem-const.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/arch/sparc/include/asm/rwsem-const.h +++ b/arch/sparc/include/asm/rwsem-const.h @@ -5,7 +5,7 @@ #define RWSEM_UNLOCKED_VALUE 0x00000000 #define RWSEM_ACTIVE_BIAS 0x00000001 #define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS 0xffff0000 +#define RWSEM_WAITING_BIAS (-0x00010000) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS #define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
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