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

Greg Kroah-Hartman
2018-08-23T15:42:02Z

On Thu, Aug 23, 2018 at 06:33:47PM +0300, Sergei Shtylyov wrote:
> 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...

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.

thanks,

greg k-h