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From: Haiyang Zhang <haiyangz@microsoft.com>
To: Dexuan Cui <decui@microsoft.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	KY Srinivasan <kys@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	"olaf@aepfle.de" <olaf@aepfle.de>,
	"apw@canonical.com" <apw@canonical.com>,
	"jasowang@redhat.com" <jasowang@redhat.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"driverdev-devel@linuxdriverproject.org"
	<driverdev-devel@linuxdriverproject.org>,
	"vkuznets@redhat.com" <vkuznets@redhat.com>,
	"marcelo.cerri@canonical.com" <marcelo.cerri@canonical.com>
Subject: RE: [PATCH] PCI: hv: Fix a __local_bh_enable_ip warning in hv_compose_msi_msg()
Date: Fri, 25 May 2018 19:51:50 +0000	[thread overview]
Message-ID: <BN6PR21MB016112A4E32D76EC669818C3CA690@BN6PR21MB0161.namprd21.prod.outlook.com> (raw)
In-Reply-To: <KL1P15301MB0006EE546A7C2567B61EA783BF6B0@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM>



> -----Original Message-----
> From: Dexuan Cui
> Sent: Tuesday, May 22, 2018 8:18 PM
> To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>; Bjorn Helgaas
> <bhelgaas@google.com>; linux-pci@vger.kernel.org; KY Srinivasan
> <kys@microsoft.com>; Stephen Hemminger <sthemmin@microsoft.com>;
> olaf@aepfle.de; apw@canonical.com; jasowang@redhat.com
> Cc: linux-kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org;
> Haiyang Zhang <haiyangz@microsoft.com>; vkuznets@redhat.com;
> marcelo.cerri@canonical.com
> Subject: [PATCH] PCI: hv: Fix a __local_bh_enable_ip warning in
> hv_compose_msi_msg()
> 
> 
> Commit de0aa7b2f97d ("PCI: hv: Fix 2 hang issues in hv_compose_msi_msg()")
> uses local_bh_disable()/enable(), because hv_pci_onchannelcallback() can also
> run in tasklet context as the channel event callback.
> 
> With CONFIG_PROVE_LOCKING=y in the latest mainline, or old kernels that
> don't have commit f71b74bca637 ("irq/softirqs: Use lockdep to assert IRQs are
> disabled/enabled"), it turns out can we trigger a warning at the beginning of
> __local_bh_enable_ip(), because the upper layer irq code can call
> hv_compose_msi_msg() with local irqs disabled.
> 
> Let's fix the warning by switching to local_irq_save()/restore(). This is not an
> issue because hv_pci_onchannelcallback() is not slow, and it not a hot path.
> 
> Fixes: de0aa7b2f97d ("PCI: hv: Fix 2 hang issues in hv_compose_msi_msg()")
> Signed-off-by: Dexuan Cui <decui@microsoft.com>
> Cc: <stable@vger.kernel.org>
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: K. Y. Srinivasan <kys@microsoft.com>
> ---

Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>

Thanks you.

  reply	other threads:[~2018-05-25 19:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-23  0:18 Dexuan Cui
2018-05-25 19:51 ` Haiyang Zhang [this message]
2018-06-07  0:14   ` Dexuan Cui
2018-06-13 20:32     ` Dexuan Cui
2018-06-13 22:15       ` Bjorn Helgaas
2018-06-13 22:50         ` Dexuan Cui
2018-06-29  9:39           ` Lorenzo Pieralisi
2018-06-30 18:13             ` Dexuan Cui

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