linux-kernel - Re: [PATCH v2 1/4] perf/core: check return value of perf_event

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]

Message-ID: <CALcN6mgDnbyn=bP_U2F9R+76MGKRv1LsSRNPOibehB1yE9nJDA@mail.gmail.com>
Date:	Wed, 17 Aug 2016 13:53:05 -0700
From:	David Carrillo-Cisneros <davidcc@...gle.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>,
	"x86@...nel.org" <x86@...nel.org>, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andi Kleen <ak@...ux.intel.com>,
	Kan Liang <kan.liang@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Vegard Nossum <vegard.nossum@...il.com>,
	Paul Turner <pjt@...gle.com>,
	Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v2 1/4] perf/core: check return value of perf_event_read IPI

> > The call to smp_call_function_single in perf_event_read() may fail and,
> > when it does, its error value is the one to return.
> >
> Please also describe the symptoms of the bug - under what circumstances may the
> smp-call fail and how does the user notice?
>
> Thanks,
>
>         Ingo
generic_exec_single only fails if cpu is invalid or not online, which
currently is not supposed to happen. Since perf_event_read's error is
not checked, I guess a WARN_ON_ONCE is needed. I'll post a rebased
version with this change.

Thanks,
David