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From: Nick Alcock <nix@esperi.org.uk>
To: Kris Van Hees <kris.van.hees@oracle.com>
Cc: dtrace@lists.linux.dev, dtrace-devel@oss.oracle.com
Subject: Re: [PATCH 15/20] libdtrace: search both ELF symbol tables for module symbols
Date: Fri, 06 Nov 2026 13:16:24 +0000	[thread overview]
Message-ID: <877biqrtg7.fsf@esperi.org.uk> (raw)
In-Reply-To: <87ik2artkr.fsf@esperi.org.uk>

On 6 Nov 2026, Nick Alcock said:

> On 30 Oct 2026, Kris Van Hees said:
>
>> Keep independent symbol and address indices for SHT_SYMTAB and SHT_DYNSYM,
>> loading strings through each table’s sh_link. Search .symtab before .dynsym
>> and include dynamic-only names in module symbol iteration.
>
> Yet noather place where one or the other strtab was overlooked. These
> mistakes all date right back to Solaris...
>
>> Preserve .symtab indices for CTF, place dynamic and external symbols in
>> separate ID ranges, and use .dynsym for CTF when .symtab is absent. Allow
>
> Except in old dicts (CTFv2, or v3 in the absence of the CTF_F_DYNSTR
> dict flag), .dynsym should be searched unconditionally for CTF.
> Preferring the symtab is wrong. (I suspect this code is basically never
> run, since it's all symtypetab stuff, and the symtypetab isn't emitted
> for kernel CTF.)

... oh wait, this is for uprobes. The symtab in use for that follows the
above rules then (and libctf does the symtypetab lookup for you, if
uprobes is using that. Don't implement it yourself simply because CTFv4
redoes this completely while retaining almost the same user-visible API,
and you don't want to change everything twice! v4 always uses the
dynsymtab, unconditionally.)

-- 
NULL && (void)

  reply	other threads:[~2026-11-06 13:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-30 19:36 [PATCH 15/20] libdtrace: search both ELF symbol tables for module symbols Kris Van Hees
2026-11-06 13:13 ` Nick Alcock
2026-11-06 13:16   ` Nick Alcock [this message]
2026-11-06 21:29     ` Kris Van Hees
2026-11-06 21:27   ` Kris Van Hees
2026-11-07 16:04   ` Kris Van Hees

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