Re: [iovisor-dev] [PATCH v2 net-next 1/5] selftests/bpf: add a test for a bug in liveness-based pruning

2017-08-23 Thread Alexei Starovoitov via iovisor-dev
On 8/23/17 7:09 AM, Edward Cree wrote: Writes in straight-line code should not prevent reads from propagating along jumps. With current verifier code, the jump from 3 to 5 does not add a read mark on 3:R0 (because 5:R0 has a write mark), meaning that the jump from 1 to 3 gets pruned as safe

Re: [iovisor-dev] [PATCH v2 net-next 1/5] selftests/bpf: add a test for a bug in liveness-based pruning

2017-08-23 Thread Daniel Borkmann via iovisor-dev
On 08/23/2017 04:09 PM, Edward Cree wrote: Writes in straight-line code should not prevent reads from propagating along jumps. With current verifier code, the jump from 3 to 5 does not add a read mark on 3:R0 (because 5:R0 has a write mark), meaning that the jump from 1 to 3 gets pruned

[iovisor-dev] [PATCH v2 net-next 1/5] selftests/bpf: add a test for a bug in liveness-based pruning

2017-08-23 Thread Edward Cree via iovisor-dev
Writes in straight-line code should not prevent reads from propagating along jumps. With current verifier code, the jump from 3 to 5 does not add a read mark on 3:R0 (because 5:R0 has a write mark), meaning that the jump from 1 to 3 gets pruned as safe even though R0 is NOT_INIT. Verifier