Re: [PATCH 4.14 210/217] PCI: OF: Fix I/O space page leak

Sergei Shtylyov
2018-08-23T15:33:54Z

On 08/23/2018 06:27 PM, Greg Kroah-Hartman wrote:
> On Thu, Aug 23, 2018 at 06:20:31PM +0300, Sergei Shtylyov wrote:
>> On 08/23/2018 02:56 PM, Greg Kroah-Hartman wrote:
>>> On Thu, Aug 23, 2018 at 01:17:28PM +0200, Greg Kroah-Hartman wrote:
>>>> On Thu, Aug 23, 2018 at 01:57:35PM +0300, Sergei Shtylyov wrote:
>>>>> On 08/23/2018 10:55 AM, Greg Kroah-Hartman wrote:
>>>>>
>>>>>> 4.14-stable review patch. If anyone has any objections, please let me know.
>>>>>>
>>>>>> ------------------
>>>>>>
>>>>>> From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>>>>>>
>>>>>> commit a5fb9fb023a1435f2b42bccd7f547560f3a21dc3 upstream.
>>>>>>
>>>>>> When testing the R-Car PCIe driver on the Condor board, if the PCIe PHY
>>>>>> driver was left disabled, the kernel crashed with this BUG:
>>>>>>
>>>>>> kernel BUG at lib/ioremap.c:72!
>>>>>> Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
>>>>>> Modules linked in:
>>>>>> CPU: 0 PID: 39 Comm: kworker/0:1 Not tainted 4.17.0-dirty #1092
>>>>>> Hardware name: Renesas Condor board based on r8a77980 (DT)
>>>>>> Workqueue: events deferred_probe_work_func
>>>>>> pstate: 80000005 (Nzcv daif -PAN -UAO)
>>>>>> pc : ioremap_page_range+0x370/0x3c8
>>>>>> lr : ioremap_page_range+0x40/0x3c8
>>>>>> sp : ffff000008da39e0
>>>>>> x29: ffff000008da39e0 x28: 00e8000000000f07
>>>>>> x27: ffff7dfffee00000 x26: 0140000000000000
>>>>>> x25: ffff7dfffef00000 x24: 00000000000fe100
>>>>>> x23: ffff80007b906000 x22: ffff000008ab8000
>>>>>> x21: ffff000008bb1d58 x20: ffff7dfffef00000
>>>>>> x19: ffff800009c30fb8 x18: 0000000000000001
>>>>>> x17: 00000000000152d0 x16: 00000000014012d0
>>>>>> x15: 0000000000000000 x14: 0720072007200720
>>>>>> x13: 0720072007200720 x12: 0720072007200720
>>>>>> x11: 0720072007300730 x10: 00000000000000ae
>>>>>> x9 : 0000000000000000 x8 : ffff7dffff000000
>>>>>> x7 : 0000000000000000 x6 : 0000000000000100
>>>>>> x5 : 0000000000000000 x4 : 000000007b906000
>>>>>> x3 : ffff80007c61a880 x2 : ffff7dfffeefffff
>>>>>> x1 : 0000000040000000 x0 : 00e80000fe100f07
>>>>>> Process kworker/0:1 (pid: 39, stack limit = 0x (ptrval))
>>>>>> Call trace:
>>>>>> ioremap_page_range+0x370/0x3c8
>>>>>> pci_remap_iospace+0x7c/0xac
>>>>>> pci_parse_request_of_pci_ranges+0x13c/0x190
>>>>>> rcar_pcie_probe+0x4c/0xb04
>>>>>> platform_drv_probe+0x50/0xbc
>>>>>> driver_probe_device+0x21c/0x308
>>>>>> __device_attach_driver+0x98/0xc8
>>>>>> bus_for_each_drv+0x54/0x94
>>>>>> __device_attach+0xc4/0x12c
>>>>>> device_initial_probe+0x10/0x18
>>>>>> bus_probe_device+0x90/0x98
>>>>>> deferred_probe_work_func+0xb0/0x150
>>>>>> process_one_work+0x12c/0x29c
>>>>>> worker_thread+0x200/0x3fc
>>>>>> kthread+0x108/0x134
>>>>>> ret_from_fork+0x10/0x18
>>>>>> Code: f9004ba2 54000080 aa0003fb 17ffff48 (d4210000)
>>>>>>
>>>>>> It turned out that pci_remap_iospace() wasn't undone when the driver's
>>>>>> probe failed, and since devm_phy_optional_get() returned -EPROBE_DEFER,
>>>>>> the probe was retried, finally causing the BUG due to trying to remap
>>>>>> already remapped pages.
>>>>>>
>>>>>> Introduce the devm_pci_remap_iospace() managed API and replace the
>>>>>> pci_remap_iospace() call with it to fix the bug.
>>>>>>
>>>>>> Fixes: dbf9826d5797 ("PCI: generic: Convert to DT resource parsing API")
>>>>>> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
>>>>>> [lorenzo.pieralisi@arm.com: split commit/updated the commit log]
>>>>>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
>>>>>> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
>>>>>> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
>>>>>> [Backport just for the new api which other patches need - gregkh]
>>>>>> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>>>>
>>>>>> ---
>>>>>> drivers/pci/pci.c | 38 ++++++++++++++++++++++++++++++++++++++
>>>>>> include/linux/pci.h | 2 ++
>>>>>> 2 files changed, 40 insertions(+)
>>>>>
>>>>> You missed a chnage to drivers/pci/host/pci-host-common.c (and
>>>>> also drivers/pci/host/pcie-rcar.c which wasn't using the generic mode back
>>
>> s/mode/code/, of course. :-)
>>
>>>>> then)...
>>>>
>>>> Yes I totally messed this up, let me fix it...
>>>
>>> Ok, below is the patch that I replaced the 4.14 and 4.9 versions with,
>>> it should now be resolved, but verifying this would be nice :)
>>
>> Unfortunately, it doesn't fix anything on R-Car where this bug was originally
>> encountered and the fix was tested... and you leave no way for it to be fixed. :-(
>
> Really? Why not? What is missing here?

You just need to fix drivers/pci/host/pcie-rcar.c in this same patch -- because
this same *upstream* patch fixed the R-Car PCIe driver in 4.18. That driver started
using the common "PCI-resource-walker" function factored out from pci-host-common.c
somewhere around 4.17, IIRC...

> greg k-h

MBR, Sergei