On 06/27/18 12:36, Daniel Borkmann wrote: > On 06/27/2018 12:13 PM, Kleber Souza wrote: >> On 06/27/18 12:01, Daniel Borkmann wrote: >>> On 06/27/2018 11:40 AM, Kleber Souza wrote: >>> [...] >>>> When I load the test_bpf module from mainline (v4.18-rc2) with >>>> CONFIG_BPF_JIT_ALWAYS_ON=y on a s390x system I get the following errors: >>>> >>>> test_bpf: #289 BPF_MAXINSNS: Ctx heavy transformations FAIL to >>>> prog_create err=-524 len=4096 >>>> test_bpf: #290 BPF_MAXINSNS: Call heavy transformations FAIL to >>>> prog_create err=-524 len=4096 >>>> [...] >>>> test_bpf: #296 BPF_MAXINSNS: exec all MSH FAIL to prog_create err=-524 >>>> len=4096 >>>> test_bpf: #297 BPF_MAXINSNS: ld_abs+get_processor_id FAIL to prog_create >>>> err=-524 len=4096 >>>> >>>> From a quick look at the code it seems that >>>> arch/s390/net/bpf_jit_comp.c:bpf_int_jit_compile() is failing to JIT >>>> compile the test code. >>>> >>>> Are those failures expected and could be flagged with FLAG_EXPECTED_FAIL >>>> on lib/test_bpf.c or are those caused by some issue with the s390x JIT >>>> compiler that needs to be fixed? >>> >>> JIT doesn't guarantee in general to map really all programs to native insns, >>> so some, mostly crafted corner cases could fail. E.g. x86-64 JIT doesn't converge >>> on some programs in test_bpf.c and thus falls back to interpreter or simply >>> rejects the program in case of CONFIG_BPF_JIT_ALWAYS_ON=y. Above would seem >>> likely that it's hitting the BPF_SIZE_MAX that s390 would do. I think it might >>> make sense to either have the FLAG_EXPECTED_FAIL in lib/test_bpf.c more fine >>> grained as a flag per arch, so we could say it's expected to fail on e.g. s390 >>> but not on x86 and the like, or just denote it as 'could potentially fail but >>> doesn't have to be the case everywhere'. >> >> Thank you for your reply. I will run some more tests to make sure we are >> hitting BPF_SIZE_MAX or what exactly is failing and send a patch to flag >> it conditionally for s390x. > > Sounds good, thanks! In any case, please let us know your findings. > > Best, > Daniel > Hi Daniel, Your presumption was correct, all four tests are failing because they exceed BPF_SIZE_MAX. I'll send a patch shortly. Thanks! Kleber -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
