linux-kernel - Re: [PATCH] x86/mce: Need to let kill_proc() send signal to doomed process

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20120710154410.GA29892@aftab.osrc.amd.com>
Date:	Tue, 10 Jul 2012 17:44:10 +0200
From:	Borislav Petkov <bp@...64.org>
To:	Tony Luck <tony.luck@...el.com>
Cc:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	Chen Gong <gong.chen@...ux.intel.com>,
	"Huang, Ying" <ying.huang@...el.com>,
	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
Subject: Re: [PATCH] x86/mce: Need to let kill_proc() send signal to doomed
 process

On Mon, Jul 09, 2012 at 01:34:36PM -0700, Tony Luck wrote:
> In commit dad1743e5993f19b3d7e7bd0fb35dc45b5326626
>   x86/mce: Only restart instruction after machine check recovery if it is safe
> 
> we fixed mce_notify_process() to force a signal to the current process
> if it was not restartable (RIPV bit not set in MCG_STATUS). But doing
> it here means that the process doesn't get told the virtual address of
> the fault via siginfo_t->si_addr. This would prevent application level
> recovery from the fault.
> 
> Make a new MF_MUST_KILL flag bit for memory_failure() et. al. to use
> so that we will provide the right information with the signal.
> 
> Signed-off-by: Tony Luck <tony.luck@...el.com>
> ---
> 
> v2: Fix brainfart where I forgot to check mi->restartable to decide whether
>     to pass in the new MF_MUST_KILL bit [Thanks Boris for spotting this!]
>     Use same style syntax !!(flags & MF_MUST_KILL) [Also from Boris]
>     Faked tests with RIPV set and not set ... and found that we need one
>     more check on MF_MUST_KILL earlier in hwpoison_user_mappings() to
>     make sure it doesn't think the clean page case is recoverable.

Ok, now it makes pretty good sense.

Acked-by: Borislav Petkov <borislav.petkov@....com>

Thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/