bpf/verifier: when pruning a branch, ignore its write marks
authorEdward Cree <ecree@solarflare.com>
Wed, 23 Aug 2017 14:10:03 +0000 (15:10 +0100)
committerDavid S. Miller <davem@davemloft.net>
Thu, 24 Aug 2017 05:38:07 +0000 (22:38 -0700)
commit63f45f840634ab5fd71bbc07acff915277764068
treecb362e59b70cfb3188d10329713764452009257e
parentd893dc26e3f42e12ae75703c52cc6de5578ff1f5
bpf/verifier: when pruning a branch, ignore its write marks

The fact that writes occurred in reaching the continuation state does
 not screen off its reads from us, because we're not really its parent.
So detect 'not really the parent' in do_propagate_liveness, and ignore
 write marks in that case.

Fixes: dc503a8ad984 ("bpf/verifier: track liveness for pruning")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
kernel/bpf/verifier.c