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

Sergei Shtylyov
2018-08-23T19:54:56Z

On 08/23/2018 06:41 PM, 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...
>
> Ok, can you send me a patch that does that please? Otherwise I really
> don't know how to exactly "fix" that at the moment.

I'd told you I could do it. :-) Sending...

> thanks,
>
> greg k-h

MBR, Sergei