Hi, I've been looking at fixing the tailcall_bpf2bpf_hierarchy failures on s390. One of the challenges is that when a BPF trampoline calls a BPF prog A, the prologue of A sets the tail call count to 0. Therefore it would be useful to know whether the trampoline is attached to some other BPF prog B, in which case A should be called using an offset equal to tail_call_start, bypassing the tail call count initialization. The trampoline attachment point is passed to trampoline functions via the orig_call variable. Unfortunately in the case of calculating the size of a struct_ops trampoline it's NULL, and I could not think of a good reason to have it this way. This series makes it always non-NULL. Best regards, Ilya Ilya Leoshkevich (2): bpf: Pass the same orig_call value to trampoline functions s390/bpf: Remove the orig_call NULL check arch/s390/net/bpf_jit_comp.c | 5 ++--- kernel/bpf/bpf_struct_ops.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) -- 2.49.0
