On Fri, Jan 29, 2021 at 07:13:21PM -0800, Alexei Starovoitov wrote: > On Fri, Jan 29, 2021 at 2:15 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > > > On Mon, Jan 25, 2021 at 5:42 PM Alexei Starovoitov > > <alexei.starovoitov@xxxxxxxxx> wrote: > > > On Mon, Jan 25, 2021 at 12:54 PM Paul Moore <paul@xxxxxxxxxxxxxx> wrote: > > > > > > > > Hello all, > > > > > > > > My apologies if this has already been reported, but I didn't see > > > > anything obvious with a quick search through the archives. I have a > > > > test program that behaves very similar to the existing > > > > selftest/bpf/test_verifier_log test that has started failing this week > > > > with v5.11-rc5; it ran without problem last week on v5.11-rc4. Is > > > > this a known problem with a fix already, or is this something new? > > > > > > > > % uname -r > > > > 5.11.0-0.rc5.134.fc34.x86_64 > > > > % pwd > > > > /.../linux/tools/testing/selftests/bpf > > > > % git log --oneline | head -n 1 > > > > 6ee1d745b7c9 Linux 5.11-rc5 > > > > % make test_verifier_log > > > > ... > > > > BINARY test_verifier_log > > > > % ./test_verifier_log > > > > Test log_level 0... > > > > Test log_size < 128... > > > > Test log_buff = NULL... > > > > Test oversized buffer... > > > > ERROR: Program load returned: ret:-1/errno:22, expected ret:-1/errno:13 > > > > > > Thanks for reporting. > > > bpf and bpf-next don't have this issue. Not sure what changed. > > > > I haven't had a chance to look into this any further, but Ondrej > > Mosnacek (CC'd) found the following today: > > > > "So I was trying to debug this further and I think I've identified what > > triggers the problem. It seems that the BTF debuginfo generation > > became broken with CONFIG_DEBUG_INFO_DWARF4=n somewhere between -rc4 > > and -rc5. It also seems to depend on a recent (Fedora Rawhide) version > > of some component of the build system (GCC, probably), because the > > problem disappeared when I tried to build the "bad" kernel in F33 > > buildroot instead of Rawhide." > > I see. There were fixes for dwarf and btf, but I lost the track. > I believe it was a combination of gcc bug that was worked around in pahole. > Arnaldo, Jiri, Andrii, > what is the status? Did all fixes land in pahole? I checked on rawhide and besides many pahole warnings, the resulted BTF data have many duplications in core structs BTFIDS vmlinux WARN: multiple IDs found for 'task_struct': 132, 1247 - using 132 WARN: multiple IDs found for 'file': 440, 1349 - using 440 WARN: multiple IDs found for 'inode': 698, 1645 - using 698 WARN: multiple IDs found for 'path': 729, 1672 - using 729 WARN: multiple IDs found for 'task_struct': 132, 2984 - using 132 WARN: multiple IDs found for 'task_struct': 132, 3043 - using 132 WARN: multiple IDs found for 'file': 440, 3085 - using 440 WARN: multiple IDs found for 'seq_file': 1469, 3125 - using 1469 WARN: multiple IDs found for 'inode': 698, 3336 - using 698 WARN: multiple IDs found for 'path': 729, 3366 - using 729 WARN: multiple IDs found for 'task_struct': 132, 5337 - using 132 WARN: multiple IDs found for 'inode': 698, 5360 - using 698 WARN: multiple IDs found for 'path': 729, 5388 - using 729 WARN: multiple IDs found for 'file': 440, 5412 - using 440 WARN: multiple IDs found for 'seq_file': 1469, 5639 - using 1469 WARN: multiple IDs found for 'task_struct': 132, 6243 - using 132 ... # gcc --version gcc (GCC) 11.0.0 20210123 (Red Hat 11.0.0-0) I'm guessing there are some DWARF changes that screwed BTF generation.. I'll check it's not covered by the fix I posted recently, but I think Arnaldo is now fixing some related stuff.. Arnaldo, maybe you are seeing same errors? I uploaded the build log from linking part to: http://people.redhat.com/~jolsa/build.out.gz jirka
