bpf: Test_progs, add test to catch retval refine error handling

2020-03-30T22:00:30Z

Before this series the verifier would clamp return bounds of bpf_get_stack() to [0, X] and this led the verifier to believe that a JMP_JSLT 0 would be false and so would prune that path. The result is anything hidden behind that JSLT would be unverified. Add a test to catch this case by hiding an goto pc-1 behind the check which will cause an infinite loop if not rejected. Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/158560423908.10843.11783152347709008373.stgit@john-Precision-5820-Tower

linux-dev/tools/testing/selftests/bpf/progs/test_get_stack_rawtp_err.c, branch linus/master

bpf: Test_progs, add test to catch retval refine error handling