linux-kernel - Re: [PATCH] perf, x86: Fix Intel shared extra MSR allocation

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:	Wed, 06 Jun 2012 09:00:17 +0800
From:	"Yan, Zheng" <zheng.z.yan@...el.com>
To:	Peter Zijlstra <peterz@...radead.org>
CC:	Stephane Eranian <eranian@...gle.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf, x86: Fix Intel shared extra MSR allocation

On 06/05/2012 09:56 PM, Peter Zijlstra wrote:
>> @@ -1157,14 +1163,14 @@ __intel_shared_reg_get_constraints(struct cpu_hw_events *cpuc,
>> >  	struct event_constraint *c = &emptyconstraint;
>> >  	struct er_account *era;
>> >  	unsigned long flags;
>> > -	int orig_idx = reg->idx;
>> > +	int idx = reg->idx;
>> >  
>> >  	/* already allocated shared msr */
>> >  	if (reg->alloc)
>> >  		return NULL; /* call x86_get_event_constraint() */
> I'm afraid that needs to be:
> 
> 	/*
> 	 * reg->alloc can be set due to existing state, so for fake cpuc
> 	 * we need to ignore this, otherwise we might fail to allocate
> 	 * proper fake state for this extra reg constraint. Also see
> 	 * the comment below.
> 	 */
> 	if (reg->alloc && !cpuc->is_fake)
> 		return NULL; /* call x86_get_event_constraints() */
> 
Agree

Regards
Yan, Zheng



--
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/