Subject: [PATCH bpf 0/2] Limit tail calls to 33 in all JIT compilers

From: Paul Chaignon <[email-masked]>
Date: Mon, 9 Dec 2019 19:51:52 +0100

The BPF interpreter and all JIT compilers, except RISC-V's and MIPS',
enforce a 33-tail calls limit at runtime.  Because of this discrepancy, a
BPF program can have a different behavior and output depending on whether
it is interpreted or JIT compiled, or depending on the underlying
architecture.

This patchset changes the RISC-V and MIPS JIT compilers to limit tail
calls to 33 instead of 32.  I have checked other BPF JIT compilers for the
same discrepancy.

Paul Chaignon (2):
  bpf, riscv: limit to 33 tail calls
  bpf, mips: limit to 33 tail calls

 arch/mips/net/ebpf_jit.c      | 9 +++++----
 arch/riscv/net/bpf_jit_comp.c | 4 ++--
 2 files changed, 7 insertions(+), 6 deletions(-)

-- 
2.17.1