linux-kernel - Re: [PATCH 0/2] scripts/gdb/symbols: make BPF debug info available to GDB

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Message-ID: <0368bc9e-b5de-4b35-9f96-1bdc32aa6b02@siemens.com>
Date: Thu, 6 Nov 2025 07:07:54 +0100
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Ilya Leoshkevich <iii@...ux.ibm.com>, Alexei Starovoitov
 <ast@...nel.org>, Daniel Borkmann <daniel@...earbox.net>,
 Andrii Nakryiko <andrii@...nel.org>, Kieran Bingham <kbingham@...nel.org>,
 Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, bpf@...r.kernel.org,
 Heiko Carstens <hca@...ux.ibm.com>, Vasily Gorbik <gor@...ux.ibm.com>,
 Alexander Gordeev <agordeev@...ux.ibm.com>
Subject: Re: [PATCH 0/2] scripts/gdb/symbols: make BPF debug info available to
 GDB

On 05.11.25 20:32, Ilya Leoshkevich wrote:
> On Thu, 2025-10-30 at 17:47 +0100, Jan Kiszka wrote:
>> On 10.07.25 13:53, Ilya Leoshkevich wrote:
>>> Hi,
>>>
>>> This series greatly simplifies debugging BPF progs when using QEMU
>>> gdbstub by providing symbol names, sizes, and line numbers to GDB.
>>>
>>> Patch 1 adds radix tree iteration, which is necessary for parsing
>>> prog_idr. Patch 2 is the actual implementation; its description
>>> contains some details on how to use this.
>>>
>>> Best regards,
>>> Ilya
>>>
>>> Ilya Leoshkevich (2):
>>>   scripts/gdb/radix-tree: add lx-radix-tree-command
>>>   scripts/gdb/symbols: make BPF debug info available to GDB
>>>
>>>  scripts/gdb/linux/bpf.py          | 253
>>> ++++++++++++++++++++++++++++++
>>>  scripts/gdb/linux/constants.py.in |   3 +
>>>  scripts/gdb/linux/radixtree.py    | 139 +++++++++++++++-
>>>  scripts/gdb/linux/symbols.py      |  77 ++++++++-
>>>  4 files changed, 462 insertions(+), 10 deletions(-)
>>>  create mode 100644 scripts/gdb/linux/bpf.py
>>>
>>
>> This wasn't picked up yet, right? Sorry for the late reply, my part
>> of
>> the "maintenance" here is best effort based.
>>
>> Looks good to me regarding integration. I haven't tried it out, I'm
>> just
>> wondering if it has notable performance impact on starting gdb or
>> interacting or when that could be the case. BPF programs are not
>> uncommon in common setups today. But if you don't want to debug them,
>> does this add unneeded overhead?
>>
>> Otherwise, I think it could move forward if it still applies (which
>> it
>> likely does).
>>
>> Jan
> 
> Thanks for taking a look!
> 
> I have to admit the performance implications are noticeable due to
> having to spawn an external process for each BPF prog.
> 
> What do you think about hiding this behind `lx-symbols --bpf` flag?

Sounds like a reasonable path.

Just one detail: I think gdb only uses a single dash for flags, thus:
lx-symbols -bpf.

Jan

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