s390/bpf: Tolerate not converging code shrinking
"BPF_MAXINSNS: Maximum possible literals" unnecessarily falls back to the interpreter because of failing sanity check in bpf_set_addr. The problem is that there are a lot of branches that can be shrunk, and doing so opens up the possibility to shrink even more. This process does not converge after 3 passes, causing code offsets to change during the codegen pass, which must never happen. Fix by inserting nops during codegen pass in order to preserve code offets. Fixes: 4e9b4a68 ("s390/bpf: Use relative long branches") Signed-off-by:Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by:
Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200717165326.6786-5-iii@linux.ibm.com
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