From: David Laight <david.laight.linux@gmail.com>
To: bot+bpf-ci@kernel.org
Cc: akpm@linux-foundation.org, pmladek@suse.com, kees@kernel.org,
linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
bpf@vger.kernel.org, jim.cromie@gmail.com, ljs@kernel.org,
thunder.leizhen@huawei.com, mcgrof@kernel.org,
andrey.grodzovsky@crowdstrike.com, rostedt@goodmis.org,
ast@kernel.org, andrii@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, eddyz87@gmail.com,
yonghong.song@linux.dev, mason@kernel.org,
ihor.solodrai@linux.dev
Subject: Re: [PATCH 2/2] kallsyms: Optimise symbol name search
Date: Thu, 1 Oct 2026 09:21:49 +0100 [thread overview]
Message-ID: <20261001092149.22e07e90@pumpkin> (raw)
In-Reply-To: <c26e2afbfa2cd71b2cf8bb0e963bb1d67dc5519bb5c4307c96b826ae5fdce269@mail.kernel.org>
On Thu, 1 Oct 2026 00:45:19 +0000 (UTC)
bot+bpf-ci@kernel.org wrote:
> > kallsyms: Optimise symbol name search
>
> TL;DR:
> - kallsyms 24-bit table struct may be padded to 4 bytes on ARM OABI, giving
> wrong offsets and a possible out-of-bounds read
I hate ARM OABI :-)
I think it is the only architecture Linus still supports that aligns
structures on 32bit boundaries.
> - weak table symbols may not read as NULL on relocatable x86-32, so the wrong
> table may be chosen
I'm not entirely happy with that bit of the code.
There is a conditional in every table index.
It is crying out for either a static branch or just compiling the file
(or selecting between two object files) once the symbol table size is known.
Either removes the need for weak symbols.
Anyone know if there is 'prior art' for a late compilation?
David
prev parent reply other threads:[~2026-10-01 8:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 13:21 [PATCH next 0/2] kallsyms: optimise symbol search by name David Laight
2026-09-30 13:21 ` [PATCH 1/2] kallsyms: Match compressed tokens on the fly during binary search David Laight
2026-09-30 13:21 ` [PATCH 2/2] kallsyms: Optimise symbol name search David Laight
2026-10-01 0:45 ` bot+bpf-ci
2026-10-01 8:21 ` David Laight [this message]
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