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

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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@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(+)
> > 
> >   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
> > 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 :)

thanks,

greg k-h

------------------------

>From a5fb9fb023a1435f2b42bccd7f547560f3a21dc3 Mon Sep 17 00:00:00 2001
From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
Date: Wed, 18 Jul 2018 15:40:26 -0500
Subject: PCI: OF: Fix I/O space page leak

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

--- a/drivers/pci/host/pci-host-common.c
+++ b/drivers/pci/host/pci-host-common.c
@@ -612,7 +612,7 @@ int pci_parse_request_of_pci_ranges(struct device *dev,
 
 		switch (resource_type(res)) {
 		case IORESOURCE_IO:
-			err = pci_remap_iospace(res, iobase);
+			err = devm_pci_remap_iospace(dev, res, iobase);
 			if (err) {
 				dev_warn(dev, "error %d: failed to map resource %pR\n",
 					 err, res);
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 97acba712e4e..316496e99da9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3579,6 +3579,44 @@ void pci_unmap_iospace(struct resource *res)
 }
 EXPORT_SYMBOL(pci_unmap_iospace);
 
+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);
+
 /**
  * devm_pci_remap_cfgspace - Managed pci_remap_cfgspace()
  * @dev: Generic device to remap IO address for
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 340029b2fb38..abd5d5e17aee 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1240,6 +1240,8 @@ int pci_register_io_range(struct fwnode_handle *fwnode, phys_addr_t addr,
 unsigned long pci_address_to_pio(phys_addr_t addr);
 phys_addr_t pci_pio_to_address(unsigned long pio);
 int pci_remap_iospace(const struct resource *res, phys_addr_t phys_addr);
+int devm_pci_remap_iospace(struct device *dev, const struct resource *res,
+			   phys_addr_t phys_addr);
 void pci_unmap_iospace(struct resource *res);
 void __iomem *devm_pci_remap_cfgspace(struct device *dev,
 				      resource_size_t offset,



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