[PATCH] selftests/powerpc: Fix out of bounds access in TM signal test

[PATCH] selftests/powerpc: Fix out of bounds access in TM signal test

[Michael Ellerman]

Gcc helpfully points out that we're accessing past the end of the gprs
array:

  tm-signal-msr-resv.c: In function 'signal_usr1':
  tm-signal-msr-resv.c:43:37: error: array subscript is above array bounds [-Werror=array-bounds]
    ucp->uc_mcontext.regs->gpr[PT_MSR] |= (7ULL);

We haven't noticed previously because -flto was hiding it somehow.

The code is confused, PT_MSR isn't a gpr, instead it's in
uc_regs->gregs, so fix it.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c b/tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c
index d86653f282b1..8c54d18b3e9a 100644
--- a/tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c
+++ b/tools/testing/selftests/powerpc/tm/tm-signal-msr-resv.c
@@ -40,7 +40,7 @@ void signal_usr1(int signum, siginfo_t *info, void *uc)
 #ifdef __powerpc64__
 	ucp->uc_mcontext.gp_regs[PT_MSR] |= (7ULL << 32);
 #else
-	ucp->uc_mcontext.regs->gpr[PT_MSR] |= (7ULL);
+	ucp->uc_mcontext.uc_regs->gregs[PT_MSR] |= (7ULL);
 #endif
 	/* Should segv on return becuase of invalid context */
 	segv_expected = 1;
-- 
2.5.0

Re: selftests/powerpc: Fix out of bounds access in TM signal test

[Michael Ellerman]

On Wed, 2016-02-03 at 12:44:31 UTC, Michael Ellerman wrote:
> Gcc helpfully points out that we're accessing past the end of the gprs
> array:
> 
>   tm-signal-msr-resv.c: In function 'signal_usr1':
>   tm-signal-msr-resv.c:43:37: error: array subscript is above array bounds [-Werror=array-bounds]
>     ucp->uc_mcontext.regs->gpr[PT_MSR] |= (7ULL);
> 
> We haven't noticed previously because -flto was hiding it somehow.
> 
> The code is confused, PT_MSR isn't a gpr, instead it's in
> uc_regs->gregs, so fix it.
> 
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc next.

https://git.kernel.org/powerpc/c/501e279c231bd8d5eed4ecea5a

cheers