linux-kernel - Re: [LKP] Re: [jump_label, x86] e7bf1ba97a: BUG:unable_to_handle_page_fault_for

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]

Date:   Mon, 28 Jun 2021 11:22:20 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     "Liu, Yujie" <yujie.liu@...el.com>
Cc:     Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>,
        "lkp@...ts.01.org" <lkp@...ts.01.org>, lkp <lkp@...el.com>,
        Josh Poimboeuf <jpoimboe@...hat.com>,
        "Sang, Oliver" <oliver.sang@...el.com>
Subject: Re: [LKP] Re: [jump_label, x86]  e7bf1ba97a:
 BUG:unable_to_handle_page_fault_for_address

On Thu, Jun 24, 2021 at 06:32:25AM +0000, Liu, Yujie wrote:
> > > [  222.094341] BUG: unable to handle page fault for address:
> > > ffffffff83ccffe0
> > 
> > I *think* the below might help, can you try?
> 
> Hi Peter Z,
> 
> We try to apply the patch on commit e7bf1ba97afdd (jump_label, x86: Emit short JMP)
> A new BUG appeared before reaching the BUG reported in previous mail.
> Full dmesg in attachment.

> > @@ -555,6 +558,7 @@ static int __jump_label_mod_text_reserved(void *start, void *end)
> >  	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
> >  	if (!try_module_get(mod))
> >  		mod = NULL;
> > +	init = mod->state == MODULE_STATE_COMING;
> >  	preempt_enable();
> > 
> >  	if (!mod)

*groan*, I'm an idiot... There's an obvious NULL pointer deref right
there.

Let me try locally first before I send yet another dud.