From: Yonghong Song <yhs@xxxxxx> Date: Thu, 5 Aug 2021 09:59:40 -0700 > On 8/4/21 12:08 AM, Kuniyuki Iwashima wrote: > > If there are no abstract sockets, this prog can output the same result > > compared to /proc/net/unix. > > > > # cat /sys/fs/bpf/unix | head -n 2 > > Num RefCount Protocol Flags Type St Inode Path > > ffff9ab7122db000: 00000002 00000000 00010000 0001 01 10623 private/defer > > > > # cat /proc/net/unix | head -n 2 > > Num RefCount Protocol Flags Type St Inode Path > > ffff9ab7122db000: 00000002 00000000 00010000 0001 01 10623 private/defer > > > > According to the analysis by Yonghong Song (See the link), the BPF verifier > > cannot load the code in the comment to print the name of the abstract UNIX > > domain socket due to LLVM optimisation. It can be uncommented once the > > LLVM code gen is improved. > > I have pushed the llvm fix to llvm14 trunk > (https://reviews.llvm.org/D107483), and filed a request to backport to > llvm13 (https://bugs.llvm.org/show_bug.cgi?id=51363), could you in the > next revision uncomment the "for" loop code and tested it with latest > llvm trunk compiler? Please also add an entry in selftests/bpf/README.rst > to mention the llvm commit https://reviews.llvm.org/D107483 is needed > for bpf_iter unix_socket selftest, otherwise, they will see an error > like ... Thank you for nice fixing so quickly! I confirmed that the uncommented code can be loaded properly with the latest LLVM master tree. :) ---8<--- $ sudo ./test_progs -t iter ... #7/14 unix:OK ... $ clang --version clang version 14.0.0 (https://github.com/llvm/llvm-project.git 8a557d8311593627efd08d03178889971d5ae02b) ... $ llvm-objdump -S bpf_iter_unix.o ... ; for (i = 1 ; i < len; i++) 110: 07 09 00 00 01 00 00 00 r9 += 1 111: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 <LBB0_18> ---8<--- In the next revision, I'll uncomment the code and add a note in README.rst about your fix.
