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

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Message-ID: <4858e841-a329-b97b-62b4-08cbe1761e45@cogentembedded.com>
Date:   Thu, 23 Aug 2018 22:54:48 +0300
From:   Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH 4.14 210/217] PCI: OF: Fix I/O space page leak

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@...entembedded.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@...entembedded.com>
>>>>>>>> [lorenzo.pieralisi@....com: split commit/updated the commit log]
>>>>>>>> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
>>>>>>>> Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
>>>>>>>> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>>>>>>>> [Backport just for the new api which other patches need - gregkh]
>>>>>>>> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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