lkml.org 
[lkml]   [2023]   [Jun]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 bpf 03/11] bpftool: use a local bpf_perf_event_value to fix accessing its fields
From
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Tue, 6 Jun 2023 14:02:44 -0700

> On Thu, Apr 21, 2022 at 12:39:04AM +0000, Alexander Lobakin wrote:
>> Fix the following error when building bpftool:
>>
>> CLANG profiler.bpf.o
>> CLANG pid_iter.bpf.o
>> skeleton/profiler.bpf.c:18:21: error: invalid application of 'sizeof' to an incomplete type 'struct bpf_perf_event_value'
>> __uint(value_size, sizeof(struct bpf_perf_event_value));
>> ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>> tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:13:39: note: expanded from macro '__uint'
>> tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helper_defs.h:7:8: note: forward declaration of 'struct bpf_perf_event_value'
>> struct bpf_perf_event_value;
>> ^
>>
>> struct bpf_perf_event_value is being used in the kernel only when
>> CONFIG_BPF_EVENTS is enabled, so it misses a BTF entry then.
>> Define struct bpf_perf_event_value___local with the
>> `preserve_access_index` attribute inside the pid_iter BPF prog to
>> allow compiling on any configs. It is a full mirror of a UAPI
>> structure, so is compatible both with and w/o CO-RE.
>> bpf_perf_event_read_value() requires a pointer of the original type,
>> so a cast is needed.
>>
>
> Hi Alexander,
> What's the status of this series? I wasn't able to find a v3 on lore.

Hi,

Sorry, I haven't been working on my private/home kernel projects for
quite a long. As Quentin mentioned, he took some patches from the series
into his own set. I'd support that one rather than mine.

>
> We received a report that OpenMandriva is carrying around this patch.
> https://github.com/ClangBuiltLinux/linux/issues/1805.
>
> + Tomasz
>
> Tomasz, do you have more info which particular configs can reproduce
> this issue? Is this patch still necessary?
>
>> Fixes: 47c09d6a9f67 ("bpftool: Introduce "prog profile" command")
>> Suggested-by: Andrii Nakryiko <andrii@kernel.org>
>> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Thanks,
Olek

\
 
 \ /
  Last update: 2023-06-07 18:21    [W:0.088 / U:1.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site