linux-kernel - Re: [PATCH] perf_counter: powerpc: add nmi_enter/nmi

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: <20090409052002.GE5352@elte.hu>
Date:	Thu, 9 Apr 2009 07:20:02 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Paul Mackerras <paulus@...ba.org>
Cc:	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] perf_counter: powerpc: add nmi_enter/nmi_exit calls


* Paul Mackerras <paulus@...ba.org> wrote:

> Impact: powerpc bug fix
> 
> Now that the core is using in_nmi() (added in e30e08f6, 
> "perf_counter: fix NMI race in task clock"), we need the powerpc 
> perf_counter_interrupt to call nmi_enter() and nmi_exit() in those 
> cases where the interrupt happens when interrupts are 
> soft-disabled.  If interrupts were soft-enabled, we can treat it 
> as a regular interrupt and do irq_enter/irq_exit around the whole 
> routine.  This lets us get rid of the test_perf_counter_pending() 
> call at the end of perf_counter_interrupt, thus simplifying things 
> a little.

applied, thanks Paul!

I'm wondering, what was the real impact? Was it a crash or some 
other misbehavior? This impact line:

	Impact: powerpc bug fix

is a bit too generic to be useful in practice. Something like:

	Impact: fix stuck NMIs on powerpc
	Impact: fix NMI crash on powerpc

would have been more descriptive about the real, hands-on impact of 
this patch.

	Ingo
--
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/