From: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> Date: Fri, 13 Aug 2021 17:26:05 -0700 > On Fri, Aug 13, 2021 at 5:21 PM Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx> wrote: > > > > From: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> > > Date: Fri, 13 Aug 2021 16:25:53 -0700 > > > On Thu, Aug 12, 2021 at 9:46 AM Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx> wrote: > > > > > > > > The iterator can output almost the same result compared to /proc/net/unix. > > > > The header line is aligned, and the Inode column uses "%8lu" because "%5lu" > > > > can be easily overflown. > > > > > > > > # cat /sys/fs/bpf/unix > > > > Num RefCount Protocol Flags Type St Inode Path > > > > > > It's totally my OCD, but why the column name is not aligned with > > > values? I mean the "Inode" column. It's left aligned, but values > > > (numbers) are right-aligned? I'd fix that while applying, but I can't > > > apply due to selftests failures, so please take a look. > > > > Ah, honestly, I've felt something strange about the column... will fix it! > > > > > > > > > > > > > > ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer > > > > ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@ > > > > > > > > # cat /proc/net/unix > > > > Num RefCount Protocol Flags Type St Inode Path > > > > ffff963c06689800: 00000002 00000000 00010000 0001 01 18697 private/defer > > > > ffff963c7c979c00: 00000002 00000000 00000000 0001 01 598245 @Hello@World@ > > > > > > > > Note that this prog requires the patch ([0]) for LLVM code gen. Thanks to > > > > Yonghong Song for analysing and fixing. > > > > > > > > [0] https://reviews.llvm.org/D107483 > > > > > > > > Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx> > > > > Acked-by: Yonghong Song <yhs@xxxxxx> > > > > --- > > > > > > This selftests breaks test_progs-no_alu32 ([0], the error log is super > > > long and can freeze browser; it looks like an infinite loop and BPF > > > verifier just keeps reporting it until it runs out of 1mln > > > instructions or something). Please check what's going on there, I > > > can't land it as it is right now. > > > > > > [0] https://github.com/kernel-patches/bpf/runs/3326071112?check_suite_focus=true#step:6:124288 > > > > > > > > > > tools/testing/selftests/bpf/README.rst | 38 +++++++++ > > > > .../selftests/bpf/prog_tests/bpf_iter.c | 16 ++++ > > > > tools/testing/selftests/bpf/progs/bpf_iter.h | 8 ++ > > > > .../selftests/bpf/progs/bpf_iter_unix.c | 77 +++++++++++++++++++ > > > > .../selftests/bpf/progs/bpf_tracing_net.h | 4 + > > > > 5 files changed, 143 insertions(+) > > > > create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_unix.c > > > > > > > > > > [...] > > > > > > > + /* The name of the abstract UNIX domain socket starts > > > > + * with '\0' and can contain '\0'. The null bytes > > > > + * should be escaped as done in unix_seq_show(). > > > > + */ > > > > + int i, len; > > > > + > > > > > > no_alu32 variant probably isn't happy about using int for this, it > > > probably does << 32, >> 32 dance and loses track of actual value in > > > the loop. You can try using u64 instead. > > > > Sorry, I missed the no_alu32 test. > > Changing int to __u64 fixed the error, thanks! > > > > > > > > > > > + len = unix_sk->addr->len - sizeof(short); > > > > + > > > > + BPF_SEQ_PRINTF(seq, " @"); > > > > + > > > > + /* unix_mkname() tests this upper bound. */ > > > > + if (len < sizeof(struct sockaddr_un)) > > > > + for (i = 1; i < len; i++) > > > > > > if you move above if inside the loop to break out of the loop, does it > > > change how Clang generates code? > > > > > > for (i = 1; i < len i++) { > > > if (i >= sizeof(struct sockaddr_un)) > > > break; > > > BPF_SEQ_PRINTF(...); > > > } > > > > Yes, but there seems little defference. > > Which is preferable? > > > > ---8<--- > > before (for inside if) <- -> after (if inside loop) > > 96: 07 08 00 00 fe ff ff ff r8 += -2 | ; for (i = 1; i < len; i++) { > > ; if (len < sizeof(struct sockaddr_un)) | 97: bf 81 00 00 00 00 00 00 r1 = r8 > > 97: 25 08 10 00 6d 00 00 00 if r8 > 109 goto +16 <LBB0_21> | 98: 07 01 00 00 fc ff ff ff r1 += -4 > > ; for (i = 1; i < len; i++) | 99: 25 01 12 00 6b 00 00 00 if r1 > 107 goto +18 <LBB0_21> > > 98: a5 08 0f 00 02 00 00 00 if r8 < 2 goto +15 <LBB0_21> | 100: 07 08 00 00 fe ff ff ff r8 += -2 > > 99: b7 09 00 00 01 00 00 00 r9 = 1 | 101: b7 09 00 00 01 00 00 00 r9 = 1 > > 100: 05 00 16 00 00 00 00 00 goto +22 <LBB0_18> | 102: b7 06 00 00 02 00 00 00 r6 = 2 > > | 103: 05 00 17 00 00 00 00 00 goto +23 <LBB0_17> > > ... > > 111: 85 00 00 00 7e 00 00 00 call 126 | 113: b4 05 00 00 08 00 00 00 w5 = 8 > > ; for (i = 1; i < len; i++) | 114: 85 00 00 00 7e 00 00 00 call 126 > > 112: 07 09 00 00 01 00 00 00 r9 += 1 | ; for (i = 1; i < len; i++) { > > 113: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 <LBB0_18> | 115: 25 08 02 00 6d 00 00 00 if r8 > 109 goto +2 <LBB0_21> > > > 116: 07 09 00 00 01 00 00 00 r9 += 1 > > > ; for (i = 1; i < len; i++) { > > > 117: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 <LBB0_17> > > ---8<--- > > > > Have you tried running the variant I proposed on Clang without > Yonghong's recent fix? I wonder if it works without that fix (not that > there is anything wrong about the fix, but if we can avoid depending > on it, it would be great). It was with the fix. I rebuilt LLVM without the fix, then the if-inside-for code worked well :) There was no transformation from '<' to '!='. I'll drop the change in README and respin with your suggestion soon. ---8<--- ; for (i = 1; i < len; i++) { 97: bf 81 00 00 00 00 00 00 r1 = r8 98: 07 01 00 00 fc ff ff ff r1 += -4 99: 25 01 12 00 6b 00 00 00 if r1 > 107 goto +18 <LBB0_21> 100: 07 08 00 00 fe ff ff ff r8 += -2 101: b7 09 00 00 01 00 00 00 r9 = 1 102: b7 06 00 00 02 00 00 00 r6 = 2 103: 05 00 17 00 00 00 00 00 goto +23 <LBB0_17> ... ; for (i = 1; i < len; i++) { 115: 25 08 02 00 6d 00 00 00 if r8 > 109 goto +2 <LBB0_21> 116: 07 09 00 00 01 00 00 00 r9 += 1 ; for (i = 1; i < len; i++) { 117: ad 89 09 00 00 00 00 00 if r9 < r8 goto +9 <LBB0_17> ---8<--- > > > > > > > > > > > > > + BPF_SEQ_PRINTF(seq, "%c", > > > > + unix_sk->addr->name->sun_path[i] ?: > > > > + '@'); > > > > + } > > > > + } > > > > + > > > > + BPF_SEQ_PRINTF(seq, "\n"); > > > > + > > > > + return 0; > > > > +} > > > > diff --git a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > index 3af0998a0623..eef5646ddb19 100644 > > > > --- a/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > +++ b/tools/testing/selftests/bpf/progs/bpf_tracing_net.h > > > > @@ -5,6 +5,10 @@ > > > > #define AF_INET 2 > > > > #define AF_INET6 10 > > > > > > > > +#define __SO_ACCEPTCON (1 << 16) > > > > +#define UNIX_HASH_SIZE 256 > > > > +#define UNIX_ABSTRACT(unix_sk) (unix_sk->addr->hash < UNIX_HASH_SIZE) > > > > + > > > > #define SOL_TCP 6 > > > > #define TCP_CONGESTION 13 > > > > #define TCP_CA_NAME_MAX 16 > > > > -- > > > > 2.30.2
