On Mon, Feb 27, 2023 at 6:32 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Mon, Feb 27, 2023 at 6:17 AM Eduard Zingerman <eddyz87@xxxxxxxxx> wrote:
> >
> > On Sun, 2023-02-26 at 03:03 +0200, Eduard Zingerman wrote:
> > > On Sat, 2023-02-25 at 20:50 +0000, Matt Bobrowski wrote:
> > > > Sorry Eduard, I replied late last night although the email bounced due
> > > > to exceeding the mail char limit. Let's try attaching a compressed
> > > > variant of the requested files, which includes the compiled kernel's
> > > > BTF and the kernel's config.
> > >
> > > Hi Matt,
> > >
> > > I tried using your config but still can't reproduce the issue.
> > > Will try to do it using debian 12 chroot tomorrow or on Monday.
> >
> > Hi Matt,
> >
> > Short update:
> > I've reproduced the issue with multiple STRUCT 'linux_binprm' BTF IDs
> > in Debian testing chroot, thank you for providing all details.
> > Attaching the instructions in the end of the email.
> > Need some time to analyze pahole behavior.
> >
>
> Try using [0] to pinpoint what actually is different between any two
> linux_binprm definitions. I've hacked up this "tool" last time I had
> to pinpoint where two BTF types diverge, maybe it will save you a bit
> of time as well. I'd like to put this functionality into btfdump
> ([1]), but I didn't get to it yet, unfortunately.
>
It's not just linux_binprm but a bunch of other structs (quite a lot
of them that seem to diverge)
[...]
WARN: multiple IDs found for 'sock_common': 4400, 53212 - using 4400
WARN: multiple IDs found for 'request_sock': 4458, 53257 - using 4458
WARN: multiple IDs found for 'task_struct': 265, 55830 - using 265
WARN: multiple IDs found for 'file': 474, 55854 - using 474
WARN: multiple IDs found for 'vm_area_struct': 480, 55857 - using 480
WARN: multiple IDs found for 'seq_file': 670, 55891 - using 670
WARN: multiple IDs found for 'sock': 3623, 55918 - using 3623
WARN: multiple IDs found for 'sk_buff': 3095, 56014 - using 3095
WARN: multiple IDs found for 'fib6_info': 8129, 56069 - using 8129
WARN: multiple IDs found for 'inode': 854, 56092 - using 854
WARN: multiple IDs found for 'path': 886, 56121 - using 886
WARN: multiple IDs found for 'cgroup': 913, 56130 - using 913
WARN: multiple IDs found for 'xdp_buff': 3838, 56558 - using 3838
WARN: multiple IDs found for 'socket': 3848, 56563 - using 3848
WARN: multiple IDs found for 'sock_common': 4400, 56890 - using 4400
WARN: multiple IDs found for 'request_sock': 4458, 56938 - using 4458
WARN: multiple IDs found for 'task_struct': 265, 58141 - using 265
WARN: multiple IDs found for 'inode': 854, 58153 - using 854
WARN: multiple IDs found for 'path': 886, 58182 - using 886
WARN: multiple IDs found for 'file': 474, 58207 - using 474
WARN: multiple IDs found for 'vm_area_struct': 480, 58210 - using 480
WARN: multiple IDs found for 'seq_file': 670, 58389 - using 670
WARN: multiple IDs found for 'task_struct': 265, 58862 - using 265
WARN: multiple IDs found for 'file': 474, 58889 - using 474
WARN: multiple IDs found for 'vm_area_struct': 480, 58892 - using 480
WARN: multiple IDs found for 'inode': 854, 58954 - using 854
WARN: multiple IDs found for 'path': 886, 58983 - using 886
WARN: multiple IDs found for 'cgroup': 913, 58992 - using 913
WARN: multiple IDs found for 'seq_file': 670, 59157 - using 670
WARN: multiple IDs found for 'sock': 3623, 59309 - using 3623
WARN: multiple IDs found for 'sk_buff': 3095, 59312 - using 3095
WARN: multiple IDs found for 'xdp_buff': 3838, 59699 - using 3838
WARN: multiple IDs found for 'socket': 3848, 59704 - using 3848
WARN: multiple IDs found for 'sock_common': 4400, 60021 - using 4400
WARN: multiple IDs found for 'request_sock': 4458, 60066 - using 4458
WARN: multiple IDs found for 'file': 474, 60890 - using 474
WARN: multiple IDs found for 'task_struct': 265, 60900 - using 265
WARN: multiple IDs found for 'vm_area_struct': 480, 60932 - using 480
WARN: multiple IDs found for 'inode': 854, 60962 - using 854
WARN: multiple IDs found for 'path': 886, 60991 - using 886
WARN: multiple IDs found for 'cgroup': 913, 61000 - using 913
WARN: multiple IDs found for 'seq_file': 670, 61174 - using 670
WARN: multiple IDs found for 'task_struct': 265, 62225 - using 265
WARN: multiple IDs found for 'file': 474, 62256 - using 474
WARN: multiple IDs found for 'vm_area_struct': 480, 62259 - using 480
WARN: multiple IDs found for 'seq_file': 670, 62289 - using 670
WARN: multiple IDs found for 'inode': 854, 62573 - using 854
WARN: multiple IDs found for 'path': 886, 62602 - using 886
[...]
BTF .btf.vmlinux.bin.o
seems to take 10+ minutes. Something seems off here, it seems like the
deduplication is failing for a lot of types which causes pahole to run
for so long.
My pahole is at:
431df45 ("btfdiff: Exclude Rust CUs since those are not yet being
converted to BTF on the Linux kernel")
Clang at:
9e5bfa1ae30b ("[AArch64] Add some tests for multiple uses of extended
vector extracts. NFC")
and kernel at:
68bfd65fb98d ("Merge branch 'move SYS() macro to test_progs.h and run
mptcp in a dedicated netns'")
and I am using the same config as vmtest.sh.
I was able to "fix" this with using clang 16.x and the following hacky pahole:
030e3b4 - core: Add DW_TAG_unspecified_type to tag__is_tag_type() set
(HEAD) (2023-02-26 Arnaldo Carvalho de Melo)
f20515b - dwarves: support DW_TAG_atomic_type (2023-02-26 David Lamparter)
de24234 - pahole: Prep 1.24 (tag: v1.24) (2022-08-22 Arnaldo Carvalho de Melo)
d6c9528 - dwarf_loader: Encode char type as signed (2022-08-10 Yonghong Song)
and the the following patch on top:
diff --git a/btf_encoder.c b/btf_encoder.c
index daa8e3b..3a29a67 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -939,6 +939,8 @@ static int btf_encoder__encode_tag(struct
btf_encoder *encoder, struct tag *tag,
return btf_encoder__add_enum_type(encoder, tag, conf_load);
case DW_TAG_subroutine_type:
return btf_encoder__add_func_proto(encoder,
tag__ftype(tag), type_id_off);
+ case DW_TAG_unspecified_type:
+ return 0;
default:
fprintf(stderr, "Unsupported DW_TAG_%s(0x%x)\n",
dwarf_tag_name(tag->tag), tag->tag);
diff --git a/dwarves.h b/dwarves.h
index f18a639..b1dc556 100644
--- a/dwarves.h
+++ b/dwarves.h
@@ -544,10 +544,8 @@ static inline int tag__is_tag_type(const struct tag *tag)
tag->tag == DW_TAG_reference_type ||
tag->tag == DW_TAG_restrict_type ||
tag->tag == DW_TAG_subroutine_type ||
- tag->tag == DW_TAG_unspecified_type ||
tag->tag == DW_TAG_volatile_type ||
tag->tag == DW_TAG_atomic_type ||
- tag->tag == DW_TAG_unspecified_type ||
tag->tag == DW_TAG_LLVM_annotation;
}
Now this is not a clean build and still has errors like:
tag__recode_dwarf_type: couldn't find 0xe82f542 type for 0xe82f4d2 (subprogram)!
tag__recode_dwarf_type: couldn't find 0xe82f542 type for 0xe82f4e2 (subprogram)!
> [0] https://github.com/libbpf/libbpf-bootstrap/tree/btfdiff-hack
> [1] https://github.com/anakryiko/btfdump
>
>
> > Thanks,
> > Eduard
> >
> > --
> >
> > host root:
> > mkdir bookworm
> > sudo debootstrap testing bookworm/ http://deb.debian.org/debian/
> > sudo mount -t proc proc bookworm/proc/
> > sudo mount -t sysfs sys bookworm/sys/
> > sudo chroot bookworm/ /bin/bash
> >
>
> [...]
