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From: poza@codeaurora.org
To: Thomas Tai <thomas.tai@oracle.com>
Cc: bhelgaas@google.com, keith.busch@intel.com,
	linux-pci@vger.kernel.org, linux-pci-owner@vger.kernel.org
Subject: Re: [PATCH 1/1] PCI/AER: prevent pcie_do_fatal_recovery from using device after it is removed
Date: Tue, 14 Aug 2018 14:52:29 +0530	[thread overview]
Message-ID: <b0104a716319d76e734c307cb4bedd9d@codeaurora.org> (raw)
In-Reply-To: <51f4b387d9bd96a42d526a6a029fc43b@codeaurora.org>

On 2018-08-14 14:46, poza@codeaurora.org wrote:
> On 2018-08-13 22:21, Thomas Tai wrote:
>> In order to prevent the pcie_do_fatal_recovery() from
>> using the device after it is removed, the device's
>> domain:bus:devfn is stored at the entry of
>> pcie_do_fatal_recovery(). After rescanning the bus, the
>> stored domain:bus:devfn is used to find the device and
>> uses to report pci_info. The original issue only happens
>> on an non-bridge device, a local variable is used instead
>> of checking the device's header type.
>> 
>> Signed-off-by: Thomas Tai <thomas.tai@oracle.com>
>> ---
>>  drivers/pci/pcie/err.c | 33 +++++++++++++++++++++++----------
>>  1 file changed, 23 insertions(+), 10 deletions(-)
>> 
>> diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
>> index f02e334..3414445 100644
>> --- a/drivers/pci/pcie/err.c
>> +++ b/drivers/pci/pcie/err.c
>> @@ -287,15 +287,20 @@ void pcie_do_fatal_recovery(struct pci_dev *dev,
>> u32 service)
>>  	struct pci_bus *parent;
>>  	struct pci_dev *pdev, *temp;
>>  	pci_ers_result_t result;
>> +	bool is_bridge_device = false;
>> +	u16 domain = pci_domain_nr(dev->bus);
>> +	u8 bus = dev->bus->number;
>> +	u8 devfn = dev->devfn;
>> 
>> -	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)
>> +	if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>> +		is_bridge_device = true;
>>  		udev = dev;
>> -	else
>> +	} else {
>>  		udev = dev->bus->self;
>> +	}
>> 
>>  	parent = udev->subordinate;
>>  	pci_lock_rescan_remove();
>> -	pci_dev_get(dev);
>>  	list_for_each_entry_safe_reverse(pdev, temp, &parent->devices,
>>  					 bus_list) {
>>  		pci_dev_get(pdev);
>> @@ -309,27 +314,35 @@ void pcie_do_fatal_recovery(struct pci_dev *dev,
>> u32 service)
>> 
>>  	result = reset_link(udev, service);
>> 
>> -	if ((service == PCIE_PORT_SERVICE_AER) &&
>> -	    (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE)) {
>> +	if (service == PCIE_PORT_SERVICE_AER && is_bridge_device) {
>>  		/*
>>  		 * If the error is reported by a bridge, we think this error
>>  		 * is related to the downstream link of the bridge, so we
>>  		 * do error recovery on all subordinates of the bridge instead
>>  		 * of the bridge and clear the error status of the bridge.
>>  		 */
>> -		pci_cleanup_aer_uncorrect_error_status(dev);
>> +		pci_cleanup_aer_uncorrect_error_status(udev);
>>  	}
>> 
>>  	if (result == PCI_ERS_RESULT_RECOVERED) {
>>  		if (pcie_wait_for_link(udev, true))
>>  			pci_rescan_bus(udev->bus);
>> -		pci_info(dev, "Device recovery from fatal error successful\n");
>> +		/* find the pci_dev after rescanning the bus */
>> +		dev = pci_get_domain_bus_and_slot(domain, bus, devfn);
> one of the motivations was to remove and re-enumerate rather then
> going thorugh driver's recovery sequence
> was; it might be possible that hotplug capable bridge, the device
> might have changed.
> hence this check will fail
>> +		if (dev)
>> +			pci_info(dev, "Device recovery from fatal error successful\n");
>> +		else
>> +			pr_err("AER: Can not find pci_dev for %04x:%02x:%02x.%x\n",
>> +			       domain, bus,
>> +			       PCI_SLOT(devfn), PCI_FUNC(devfn));
>> +		pci_dev_put(dev);
>>  	} else {
>> -		pci_uevent_ers(dev, PCI_ERS_RESULT_DISCONNECT);
>> -		pci_info(dev, "Device recovery from fatal error failed\n");
>> +		if (is_bridge_device)
> previously there was no condition.. why is this required now ?
> and it was doing on "dev" while you are doing it on "udev"
is that the reason we dont watnt o use dev after it is removed ? instead 
do pci_uevent_ers on bridge ?
>> +			pci_uevent_ers(udev, PCI_ERS_RESULT_DISCONNECT);
>> +		pr_err("AER: Device %04x:%02x:%02x.%x recovery from fatal error 
>> failed\n",
>> +		       domain, bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
>>  	}
>> 
>> -	pci_dev_put(dev);
>>  	pci_unlock_rescan_remove();
>>  }
> 
> Regards,
> Oza.

  reply	other threads:[~2018-08-14 12:08 UTC|newest]

Thread overview: 91+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-13 16:51 [PATCH 0/1] PCI/AER: prevent pcie_do_fatal_recovery from using device after it is removed Thomas Tai
2018-08-13 16:51 ` [PATCH 1/1] " Thomas Tai
2018-08-14  9:16   ` poza
2018-08-14  9:22     ` poza [this message]
2018-08-14 13:51       ` Thomas Tai
2018-08-15 14:57         ` poza
2018-08-15 15:02           ` Thomas Tai
2018-08-15 15:26             ` poza
2018-08-15 15:43               ` Thomas Tai
2018-08-15 15:59                 ` poza
2018-08-15 16:04                   ` Thomas Tai
2018-08-15 21:55       ` Benjamin Herrenschmidt
2018-08-15 21:56       ` Benjamin Herrenschmidt
2018-08-16  6:36         ` poza
2018-08-16  6:51           ` Benjamin Herrenschmidt
2018-08-16  6:59             ` Benjamin Herrenschmidt
2018-08-16  8:07               ` poza
2018-08-16  8:12                 ` Benjamin Herrenschmidt
2018-08-16  9:03                   ` poza
2018-08-16 10:07                     ` Benjamin Herrenschmidt
2018-08-16 14:11                       ` poza
2018-08-16 23:30                         ` Benjamin Herrenschmidt
2018-08-17 10:29                           ` poza
2018-08-17 10:44                             ` poza
2018-08-18  7:38                             ` Benjamin Herrenschmidt
2018-08-16  7:05             ` Benjamin Herrenschmidt
2018-08-16  7:15               ` Benjamin Herrenschmidt
2018-08-16  7:56                 ` poza
2018-08-16  8:10                   ` Benjamin Herrenschmidt
2018-08-16  8:05               ` poza
2018-08-16  8:15                 ` Benjamin Herrenschmidt
2018-08-16  8:22                   ` poza
2018-08-16  8:28                     ` Benjamin Herrenschmidt
2018-08-16 13:30                       ` Thomas Tai
2018-08-16 13:46                     ` Sinan Kaya
2018-08-16 23:27                       ` Benjamin Herrenschmidt
2018-08-17  6:35                         ` poza
2018-08-19  2:24                         ` Bjorn Helgaas
2018-08-20  5:09                           ` poza
2018-08-20  5:15                             ` Benjamin Herrenschmidt
2018-08-20 13:02                               ` Thomas Tai
2018-08-20 13:27                                 ` Benjamin Herrenschmidt
2018-08-19  2:19               ` Bjorn Helgaas
2018-08-19 21:41                 ` Sinan Kaya
2018-08-20  2:03                   ` Benjamin Herrenschmidt
2018-08-20  5:19                     ` poza
2018-08-20  5:33                       ` Benjamin Herrenschmidt
2018-08-20  7:56                         ` poza
2018-08-20 11:22                           ` Benjamin Herrenschmidt
2018-08-20 13:26                             ` poza
2018-08-20 21:02                               ` Benjamin Herrenschmidt
2018-08-21  5:14                                 ` poza
2018-08-21  6:06                                   ` Benjamin Herrenschmidt
2018-08-21 14:37                                     ` Keith Busch
2018-08-21 15:07                                       ` Sinan Kaya
2018-08-21 15:29                                         ` Keith Busch
2018-08-21 15:50                                           ` Sinan Kaya
2018-08-21 15:55                                             ` Sinan Kaya
2018-08-21 16:44                                             ` Keith Busch
2018-08-21 15:30                                       ` poza
2018-08-21 21:14                                       ` Benjamin Herrenschmidt
2018-08-21 22:04                                         ` Keith Busch
2018-08-21 22:33                                           ` Keith Busch
2018-08-21 23:06                                           ` Benjamin Herrenschmidt
2018-08-21 23:13                                             ` Keith Busch
2018-08-22  0:36                                               ` Benjamin Herrenschmidt
2018-08-30  0:01                                             ` Keith Busch
2018-08-30  0:10                                               ` Sinan Kaya
2018-08-30  0:46                                                 ` Keith Busch
2018-08-30  4:26                                               ` Benjamin Herrenschmidt
2018-08-20 15:53                             ` Keith Busch
2018-08-20 16:13                               ` poza
2018-08-20 16:32                                 ` Keith Busch
2018-08-20 21:05                               ` Benjamin Herrenschmidt
2018-08-20 21:21                                 ` Sinan Kaya
2018-08-20 21:35                                   ` Keith Busch
2018-08-20 21:53                                     ` Benjamin Herrenschmidt
2018-08-20 22:02                                       ` Sinan Kaya
2018-08-20 22:04                                         ` Benjamin Herrenschmidt
2018-08-20 22:13                                           ` Sinan Kaya
2018-08-20 22:19                                             ` Benjamin Herrenschmidt
2018-08-22  9:13                                             ` Lukas Wunner
2018-08-22 14:38                                               ` Keith Busch
2018-08-22 14:51                                                 ` Sinan Kaya
2018-08-20 22:13                                           ` Keith Busch
2018-08-20 22:19                                             ` Benjamin Herrenschmidt
2018-08-21  1:30                                               ` Keith Busch
2018-08-20  4:37                 ` Benjamin Herrenschmidt
2018-08-20  4:39                 ` PATCH] Partial revert of "PCI/AER: Handle ERR_FATAL with removal and re-enumeration of devices" Benjamin Herrenschmidt
2018-08-21 19:50                   ` Bjorn Helgaas
2018-08-22  4:35                     ` poza

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