On Mon, 2021-08-09 at 11:34 +0200, Johan Almbladh wrote: > Before, the eBPF JIT allowed up to MAX_TAIL_CALL_CNT + 1 tail calls. > Now, precisely MAX_TAIL_CALL_CNT is allowed, which is in line with the > behaviour of the interpreter. Verified with the test_bpf test suite > on qemu-system-s390x. > > Signed-off-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx> > --- > arch/s390/net/bpf_jit_comp.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/s390/net/bpf_jit_comp.c > b/arch/s390/net/bpf_jit_comp.c > index 88419263a89a..f6cdf13285ed 100644 > --- a/arch/s390/net/bpf_jit_comp.c > +++ b/arch/s390/net/bpf_jit_comp.c > @@ -1363,7 +1363,7 @@ static noinline int bpf_jit_insn(struct bpf_jit > *jit, struct bpf_prog *fp, > jit->prg); > > /* > - * if (tail_call_cnt++ > MAX_TAIL_CALL_CNT) > + * if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT) > * goto out; > */ > > @@ -1377,8 +1377,8 @@ static noinline int bpf_jit_insn(struct bpf_jit > *jit, struct bpf_prog *fp, > EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, > REG_15, off); > /* clij %w1,MAX_TAIL_CALL_CNT,0x2,out */ This comment needs to be updated as well. > patch_2_clij = jit->prg; > - EMIT6_PCREL_RIEC(0xec000000, 0x007f, REG_W1, > MAX_TAIL_CALL_CNT, > - 2, jit->prg); > + EMIT6_PCREL_RIEC(0xec000000, 0x007f, REG_W1, > + MAX_TAIL_CALL_CNT - 1, 2, jit->prg); > > /* > * prog = array->ptrs[index]; With that: Tested-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> Acked-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
