From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Fri, 5 Jun 2015 15:45:40 +0100 Subject: [PATCH 1/2] arm64: perf: Don't use of_node after putting it In-Reply-To: <1433364818-6682-1-git-send-email-sboyd@codeaurora.org> References: <1433364818-6682-1-git-send-email-sboyd@codeaurora.org> Message-ID: <20150605144539.GC7420@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Stephen, On Wed, Jun 03, 2015 at 09:53:37PM +0100, Stephen Boyd wrote: > It's possible, albeit unlikely, that using the of_node here will > reference freed memory. Call of_node_put() after printing the > name to be safe. > > Signed-off-by: Stephen Boyd > --- > arch/arm64/kernel/perf_event.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index 702591f6180a..8af7784a8e35 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -1340,12 +1340,13 @@ static int armpmu_device_probe(struct platform_device *pdev) > if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL)) > break; > > - of_node_put(dn); > if (cpu >= nr_cpu_ids) { > pr_warn("Failed to find logical CPU for %s\n", > dn->name); > + of_node_put(dn); > break; > } > + of_node_put(dn); > > irqs[i] = cpu; > } Yeah, I agree this needs changing but given (a) the CPU node isn't going to disappear and (b) this patch will conflict horribly with my queue for 4.2, do you mind if I sit on this until after the merge window (as a fix for 4.2)? Will From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423083AbbFEOpt (ORCPT ); Fri, 5 Jun 2015 10:45:49 -0400 Received: from foss.arm.com ([217.140.101.70]:44449 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932689AbbFEOpn (ORCPT ); Fri, 5 Jun 2015 10:45:43 -0400 Date: Fri, 5 Jun 2015 15:45:40 +0100 From: Will Deacon To: Stephen Boyd Cc: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH 1/2] arm64: perf: Don't use of_node after putting it Message-ID: <20150605144539.GC7420@arm.com> References: <1433364818-6682-1-git-send-email-sboyd@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1433364818-6682-1-git-send-email-sboyd@codeaurora.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Stephen, On Wed, Jun 03, 2015 at 09:53:37PM +0100, Stephen Boyd wrote: > It's possible, albeit unlikely, that using the of_node here will > reference freed memory. Call of_node_put() after printing the > name to be safe. > > Signed-off-by: Stephen Boyd > --- > arch/arm64/kernel/perf_event.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c > index 702591f6180a..8af7784a8e35 100644 > --- a/arch/arm64/kernel/perf_event.c > +++ b/arch/arm64/kernel/perf_event.c > @@ -1340,12 +1340,13 @@ static int armpmu_device_probe(struct platform_device *pdev) > if (arch_find_n_match_cpu_physical_id(dn, cpu, NULL)) > break; > > - of_node_put(dn); > if (cpu >= nr_cpu_ids) { > pr_warn("Failed to find logical CPU for %s\n", > dn->name); > + of_node_put(dn); > break; > } > + of_node_put(dn); > > irqs[i] = cpu; > } Yeah, I agree this needs changing but given (a) the CPU node isn't going to disappear and (b) this patch will conflict horribly with my queue for 4.2, do you mind if I sit on this until after the merge window (as a fix for 4.2)? Will