linux-kernel - Re: [PATCH] powerpc: Make doorbell check preemption safe

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] [day] [month] [year] [list]

Date:	Thu, 04 Jun 2015 12:15:12 +0530
From:	Shreyas B Prabhu <shreyas@...ux.vnet.ibm.com>
To:	Michael Neuling <mikey@...ling.org>
CC:	mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
	linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] powerpc: Make doorbell check preemption safe



On Wednesday 20 May 2015 06:30 AM, Michael Neuling wrote:
> On Wed, 2015-05-20 at 00:30 +0530, Shreyas B. Prabhu wrote:
>> Doorbell can be used to cause ipi on cpus which are sibling threads on
>> the same core. So icp_native_cause_ipi checks if the destination cpu
>> is a sibling thread of the current cpu and uses doorbell in such cases.
>>
>> But while running with CONFIG_PREEMPT=y, since this section is
>> preemtible, we can run into issues if after we check if the destination
>> cpu is a sibling cpu, the task gets migrated from a sibling cpu to a
>> cpu on another core.
>>
>> Fix this by using get_cpu()/ put_cpu()
> 
> Thanks.  Looks good and it's boots for me.
> 
> Signed-off-by: Michael Neuling <mikey@...ling.org>
> 
mikey, Thanks!


mpe, if this looks ok, can you please pick it up?

--
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/