On Mo, 2014-10-20 at 14:54 -0700, Alexei Starovoitov wrote:
> while comparing for verifier state equivalency the comparison
> was missing a check for uninitialized register.
> Make sure it does so and add a testcase.
>
> Fixes: f1bca824dabb ("bpf: add search pruning optimization to verifier")
> Cc: Hannes Frederic Sowa <han...@stressinduktion.org>
> Signed-off-by: Alexei Starovoitov <a...@plumgrid.com>
> ---
>
> while we were staring at the verifier code with Hannes during LPC
> something felt odd in this spot. Yes. It was a bug. Fix it.
>
> kernel/bpf/verifier.c | 3 ++-
> samples/bpf/test_verifier.c | 11 +++++++++++
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 801f5f3..9f81818 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -1409,7 +1409,8 @@ static bool states_equal(struct verifier_state *old,
> struct verifier_state *cur)
> if (memcmp(&old->regs[i], &cur->regs[i],
> sizeof(old->regs[0])) != 0) {
> if (old->regs[i].type == NOT_INIT ||
> - old->regs[i].type == UNKNOWN_VALUE)
> + (old->regs[i].type == UNKNOWN_VALUE &&
> + cur->regs[i].type != NOT_INIT))
> continue;
> return false;
> }
That makes sense.
Acked-by: Hannes Frederic Sowa <han...@stressinduktion.org>
Thanks,
Hannes
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