Re: [RFC] kallsyms: embed source file:line info in kernel stack traces

Vlastimil Babka (SUSE)
2026-03-03T09:04:56Z

On 3/3/26 07:48, Tomasz Figa wrote:
>> > Memory footprint measured with a simple KVM guest x86_64 config:
>> >
>> > Table: 4,597,583 entries from 4,841 source files
>> > lineinfo_addrs[] 4,597,583 x u32 = 17.5 MiB
>> > lineinfo_file_ids[] 4,597,583 x u16 = 8.8 MiB
>> > lineinfo_lines[] 4,597,583 x u32 = 17.5 MiB
>> > file_offsets + filenames ~ 0.1 MiB
>> > Total .rodata increase: ~ 44.0 MiB
>> >
>> > vmlinux (stripped): 529 MiB -> 573 MiB (+44 MiB / +8.3%)
>>
>> Hm, that's a significant increase.
>
> Random idea: Could this additional information (and I guess the code
> that uses it too) be moved out to a loadable module?
>
> The obvious limitation would be that the user would need to have the
> module loaded for the decoding to work, but that could be worked
> around by marking it for autoload when a crash is noticed the first
> time and then getting a better report the second time.

IMHO that's too big of a disadvantage. Many crashes are rare and either you
have this always enabled, or you missed your only chance.

> Best,
> Tomasz
>