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

Sergei Shtylyov
2018-08-23T11:08:12Z

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@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(+)

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