Re: [PATCH 4.9 124/130] PCI: OF: Fix I/O space page leak

[Sergei Shtylyov]

On 08/23/2018 10:54 AM, Greg Kroah-Hartman wrote:

> 4.9-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
> 
> 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@xxxxxxxxxxxxxxxxxx>
> [lorenzo.pieralisi@xxxxxxx: split commit/updated the commit log]
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> [Backport just for the new api which other patches need - gregkh]
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  drivers/pci/pci.c   |   38 ++++++++++++++++++++++++++++++++++++++
>  include/linux/pci.h |    2 ++
>  2 files changed, 40 insertions(+)

   Again, you missed a change to drivers/pci/host/pci-host-common.c (and 
also drivers/pci/host/pcie-rcar.c which wasn't using the generic code back
then)...

[...]

MBR, Sergei