powerpc/signal32: Fix sigset_t conversion when copying to user

On PPC64, put_sigset_t converts a sigset_t to a compat_sigset_t
before copying it to userspace. There is a typo in the case that
we have 4 words to copy, meaning that we corrupt the compat_sigset_t.

It appears that _NSIG_WORDS can't be greater than 2 at the moment
so this code is probably always optimised away anyway.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/kernel/signal_32.c b/arch/powerpc/kernel/signal_32.c
index 78b76dc..836a5a1 100644 (file)
--- a/arch/powerpc/kernel/signal_32.c
+++ b/arch/powerpc/kernel/signal_32.c
@@ -97,7 +97,7 @@ static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set)
        compat_sigset_t cset;
 
        switch (_NSIG_WORDS) {
-       case 4: cset.sig[5] = set->sig[3] & 0xffffffffull;
+       case 4: cset.sig[6] = set->sig[3] & 0xffffffffull;
                cset.sig[7] = set->sig[3] >> 32;
        case 3: cset.sig[4] = set->sig[2] & 0xffffffffull;
                cset.sig[5] = set->sig[2] >> 32;