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In-Reply-To: <aa8dd4f5b50686871c9d3a1c27337006b1c9eea9.1427200114.git.jstancek@redhat.com>
To: Jan Stancek <jstancek@redhat.com>, linuxppc-dev@lists.ozlabs.org
From: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, paulus@samba.org, anton@samba.org,
        tj@kernel.org, cl@linux.com, jolsa@redhat.com, jstancek@redhat.com,
        joel@jms.id.au
Subject: Re: powerpc/perf: add missing put_cpu_var in power_pmu_event_init
Message-Id: <20150325052509.C995F1400F1@ozlabs.org>
Date: Wed, 25 Mar 2015 16:25:09 +1100 (AEDT)
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On Tue, 2015-24-03 at 12:33:22 UTC, Jan Stancek wrote:
> One path in power_pmu_event_init() calls get_cpu_var(), but is
> missing matching call to put_cpu_var(), which causes preemption
> imbalance and crash in user-space:
> 
>   Page fault in user mode with in_atomic() = 1 mm = c000001fefa5a280
>   NIP = 3fff9bf2cae0  MSR = 900000014280f032
>   Oops: Weird page fault, sig: 11 [#23]

<snip>

Thanks. But I don't see this. I guess you have CONFIG_PREEMPT enabled?

cheers