linux-kernel - Re: [PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250213024507.mvjkalvyqsxihp54@jpoimboe>
Date: Wed, 12 Feb 2025 18:45:07 -0800
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Song Liu <song@...nel.org>
Cc: Weinan Liu <wnliu@...gle.com>, Steven Rostedt <rostedt@...dmis.org>,
	Indu Bhagat <indu.bhagat@...cle.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Mark Rutland <mark.rutland@....com>, roman.gushchin@...ux.dev,
	Will Deacon <will@...nel.org>, Ian Rogers <irogers@...gle.com>,
	linux-toolchains@...r.kernel.org, linux-kernel@...r.kernel.org,
	live-patching@...r.kernel.org, joe.lawrence@...hat.com,
	linux-arm-kernel@...ts.infradead.org,
	Puranjay Mohan <puranjay@...nel.org>
Subject: Re: [PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

On Wed, Feb 12, 2025 at 06:36:04PM -0800, Song Liu wrote:
> > > [   81.261748]  copy_process+0xfdc/0xfd58 [livepatch_special_static]
> >
> > Does that copy_process+0xfdc/0xfd58 resolve to this line in
> > copy_process()?
> >
> >                         refcount_inc(&current->signal->sigcnt);
> >
> > Maybe the klp rela reference to 'current' is bogus, or resolving to the
> > wrong address somehow?
> 
> It resolves the following line.
> 
> p->signal->tty = tty_kref_get(current->signal->tty);
> 
> I am not quite sure how 'current' should be resolved.

Hm, on arm64 it looks like the value of 'current' is stored in the
SP_EL0 register.  So I guess that shouldn't need any relocations.

> The size of copy_process (0xfd58) is wrong. It is only about
> 5.5kB in size. Also, the copy_process function in the .ko file
> looks very broken. I will try a few more things.

Ah ok, sounds like it's pretty borked.

-- 
Josh