Re: [PATCH 4.9.y] PCI: OF: Fix I/O space page leak

[Sergei Shtylyov]

On 08/23/2018 11:04 PM, Sergei Shtylyov wrote:

> 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>
> 
> ---
>  drivers/pci/host/pci-host-common.c |    2 -
>  drivers/pci/host/pcie-rcar.c       |    2 -
>  drivers/pci/pci.c                  |   38 +++++++++++++++++++++++++++++++++++++
>  include/linux/pci.h                |    2 +
>  4 files changed, 42 insertions(+), 2 deletions(-)

[...]
> Index: linux-stable/drivers/pci/pci.c
> ===================================================================
> --- linux-stable.orig/drivers/pci/pci.c
> +++ linux-stable/drivers/pci/pci.c
> @@ -3436,6 +3436,44 @@ char * __weak __init pcibios_setup(char
>  	return str;
>  }
>  
> +static void devm_pci_unmap_iospace(struct device *dev, void *ptr)
> +{
> +	struct resource **res = ptr;
> +
> +	pci_unmap_iospace(*res);
> +}
> +
> +/**
> + * devm_pci_remap_iospace - Managed pci_remap_iospace()
> + * @dev: Generic device to remap IO address for
> + * @res: Resource describing the I/O space
> + * @phys_addr: physical address of range to be mapped
> + *
> + * Managed pci_remap_iospace().  Map is automatically unmapped on driver
> + * detach.
> + */
> +int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
> +			   phys_addr_t phys_addr)
> +{
> +	const struct resource **ptr;
> +	int error;
> +
> +	ptr = devres_alloc(devm_pci_unmap_iospace, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr)
> +		return -ENOMEM;
> +
> +	error = pci_remap_iospace(res, phys_addr);
> +	if (error) {
> +		devres_free(ptr);
> +	} else	{
> +		*ptr = res;
> +		devres_add(dev, ptr);
> +	}
> +
> +	return error;
> +}
> +EXPORT_SYMBOL(devm_pci_remap_iospace);
> +

   Sorry, this hunk was misplaced. Too hasty, reposting...

>  /**
>   * pcibios_set_master - enable PCI bus-mastering for device dev
>   * @dev: the PCI device to enable
[...]

MBR, Sergei