Hi, Enclosed are a pair of patches for an oops that can occur if an exception is generated while a bpf subprogram is running. One of the bpf_prog_aux entries for the subprograms are missing an extable. This can lead to an exception that would otherwise be handled turning into a NULL pointer bug.
These changes were tested via the verifier and progs selftests and no regressions were observed.
Changes from v3: - Selftest style fixups (Feedback from Yonghong Song) - Selftest needs to assert that test bpf program executed (Feedback from Yonghong Song) - Selftest should combine open and load using open_and_load (Feedback from Yonghong Song)
Changes from v2: - Insert only the main program's kallsyms (Feedback from Yonghong Song and Alexei Starovoitov) - Selftest should use ASSERT instead of CHECK (Feedback from Yonghong Song) - Selftest needs some cleanup (Feedback from Yonghong Song) - Switch patch order (Feedback from Alexei Starovoitov)
Changes from v1: - Add a selftest (Feedback From Alexei Starovoitov) - Move to a 1-line verifier change instead of searching multiple extables
Krister Johansen (2): bpf: ensure main program has an extable selftests/bpf: add a test for subprogram extables
kernel/bpf/verifier.c | 6 ++- .../bpf/prog_tests/subprogs_extable.c | 29 +++++++++++ .../bpf/progs/test_subprogs_extable.c | 51 +++++++++++++++++++ 3 files changed, 84 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/subprogs_extable.c create mode 100644 tools/testing/selftests/bpf/progs/test_subprogs_extable.c