I noticed two more bugs while reviewing the code, description and examples available in the patches. One leads to incorrect subprog index to be stored in the frame stack maintained by the function (leading to incorrect tail_call_reachable marks, among other things). The other problem is missing exploration pass of other async callbacks when they are not called from the main prog. Call chains rooted at them can thus bypass the stack limits (32 call frames * max permitted stack depth per function). Changelog: ---------- v1 -> v2 v1: https://lore.kernel.org/bpf/20230713003118.1327943-1-memxor@xxxxxxxxx * Fix commit message for patch 2 (Alexei) Kumar Kartikeya Dwivedi (3): bpf: Fix subprog idx logic in check_max_stack_depth bpf: Repeat check_max_stack_depth for async callbacks selftests/bpf: Add more tests for check_max_stack_depth bug kernel/bpf/verifier.c | 32 +++++++++++++++---- .../selftests/bpf/progs/async_stack_depth.c | 25 +++++++++++++-- 2 files changed, 48 insertions(+), 9 deletions(-) base-commit: 9840036786d90cea11a90d1f30b6dc003b34ee67 -- 2.40.1
