linux-kernel - Re: [PATCH] powerpc/perf: Fix for core/nest imc call trace on cpuhotplug

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:   Thu, 21 Sep 2017 14:34:57 +1000
From:   Michael Ellerman <mpe@...erman.id.au>
To:     Anju T Sudhakar <anju@...ux.vnet.ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        maddy@...ux.vnet.ibm.com, hemant@...ux.vnet.ibm.com,
        anju@...ux.vnet.ibm.com
Subject: Re: [PATCH] powerpc/perf: Fix for core/nest imc call trace on cpuhotplug

Anju T Sudhakar <anju@...ux.vnet.ibm.com> writes:

> Nest/core pmu units are enabled only when it is used. A reference count is
> maintained for the events which uses the nest/core pmu units. Currently in
> *_imc_counters_release function a WARN() is used for notification of any
> underflow of ref count. Replace WARN() with a pr_info since it is an overkill.

As discussed elsewhere this is not the right solution.

If it's OK for the reference count to be negative, then we shouldn't
print anything when it is.

But I don't understand how it can be OK for the refcount to be negative.
That means someone has a negative number of references to something?

cheers