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

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Date:   Thu, 23 Aug 2018 17:27:17 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
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 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@...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?

greg k-h