Re: [PATCH] ppc/EEH: fix crash when adding a device in a slot with DDW
On Fri, Dec 28, 2012 at 01:18:24PM +0800, Gavin Shan wrote:
> On Thu, Dec 27, 2012 at 02:34:00PM -0200, Thadeu Lima de Souza Cascardo wrote:
> >The DDW code uses a eeh_dev struct from the pci_dev. However, this is
> >not set until eeh_add_device_late is called.
> >
> >Since pci_bus_add_devices is called before eeh_add_device_late, the PCI
> >devices are added to the bus, making drivers' probe hooks to be called.
> >These will call set_dma_mask, which will call the DDW code, which will
> >require the eeh_dev struct from pci_dev. This would result in a crash,
> >due to a NULL dereference.
> >
> >Calling eeh_add_device_late after pci_bus_add_devices would make the
> >system BUG, because device files shouldn't be added to devices there
> >were not added to the system. So, a new function is needed to add such
> >files only after pci_bus_add_devices have been called.
> >
>
> Could you please explain for a bit how did you trigger the problem? I'm
> not sure you got it while doing PCI hotplug or just saw the issue during
> system bootup stage :-)
>
I did a DLPAR remove followed by a DLPAR add, using drmgr -r and drmgr
-a. The reason the issue is not trigerred during bootup is that there is
no driver registered yet. So no driver probe will call dma_set_mask.
> >Cc: sta...@vger.kernel.org
> >Signed-off-by: Thadeu Lima de Souza Cascardo
> >---
> > arch/powerpc/include/asm/eeh.h |3 +++
> > arch/powerpc/kernel/pci-common.c |7 +--
> > arch/powerpc/platforms/pseries/eeh.c | 24 +++-
> > 3 files changed, 31 insertions(+), 3 deletions(-)
> >
> >diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
> >index b0ef738..71aac19 100644
> >--- a/arch/powerpc/include/asm/eeh.h
> >+++ b/arch/powerpc/include/asm/eeh.h
> >@@ -201,6 +201,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev);
> > void __init eeh_addr_cache_build(void);
> > void eeh_add_device_tree_early(struct device_node *);
> > void eeh_add_device_tree_late(struct pci_bus *);
> >+void eeh_add_device_tree_files(struct pci_bus *);
>
> Since the function is going to add EEH specific sysfs files, its name would
> be something like "eeh_add_sysfs_files" instead of
> "eeh_add_device_tree_files" :-)
It's indeed a better name.
>
> > void eeh_remove_bus_device(struct pci_dev *, int);
> >
> > /**
> >@@ -240,6 +241,8 @@ static inline void eeh_add_device_tree_early(struct
> >device_node *dn) { }
> >
> > static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
> >
> >+static inline void eeh_add_device_tree_files(struct pci_bus *bus) { }
> >+
>
> It'd better to rename the function name to "eeh_add_sysfs_files" mentioned
> as above.
>
> > static inline void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe)
> > { }
> >
> > static inline void eeh_lock(void) { }
> >diff --git a/arch/powerpc/kernel/pci-common.c
> >b/arch/powerpc/kernel/pci-common.c
> >index 7f94f76..7b1f14c 100644
> >--- a/arch/powerpc/kernel/pci-common.c
> >+++ b/arch/powerpc/kernel/pci-common.c
> >@@ -1480,11 +1480,14 @@ void pcibios_finish_adding_to_bus(struct pci_bus
> >*bus)
> > pcibios_allocate_bus_resources(bus);
> > pcibios_claim_one_bus(bus);
> >
> >+/* Fixup EEH */
> >+eeh_add_device_tree_late(bus);
> >+
> > /* Add new devices to global lists. Register in proc, sysfs. */
> > pci_bus_add_devices(bus);
> >
> >-/* Fixup EEH */
> >-eeh_add_device_tree_late(bus);
> >+/* Add EEH sysfs files */
> >+eeh_add_device_tree_files(bus);
>
> The function name would be "eeh_add_sysfs_files" as above.
>
> > }
> > EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
> >
>
> By the way, arch/powerpc/kernel/of_platform.c::of_pci_phb_probe is also
> calling
> to eeh_add_device_tree_late() as well. Since you have removed part of the
> logic
> from original eeh_add_device_tree_late(), which is add EEH specific sysfs
> files,
> and you put that part of logic to eeh_add_device_tree_files(). So I think you
> also need make the similiar change for of_pci_phb_probe() as well :-)
>
Good point. I will look into other call sites. However, I don't have
access to other platforms to test the patch.
> >diff --git a/arch/powerpc/platforms/pseries/eeh.c
> >b/arch/powerpc/platforms/pseries/eeh.c
> >index 9a04322..a667a34 100644
> >--- a/arch/powerpc/platforms/pseries/eeh.c
> >+++ b/arch/powerpc/platforms/pseries/eeh.c
> >@@ -788,7 +788,6 @@ static void eeh_add_device_late(struct pci_dev *dev)
> > dev->dev.archdata.edev = edev;
> >
> > eeh_addr_cache_insert_dev(dev);
> >-eeh_sysfs_add_device(dev);
> > }
> >
> > /**
> >@@ -815,6 +814,29 @@ void eeh_add_device_tree_late(struct pci_bus *bus)
> > EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
> >
> > /**
> >+ * eeh_add_device_tree_files - Add EEH sysfs files for the indicated PCI bus
> >+ * @bus: PCI bus
> >+ *
> >+ * This routine must be used to add EEH sysfs files for PCI
> >+ * devices which are attached to the indicated PCI bus. The PCI bus
>
Re: [PATCH] ppc/EEH: fix crash when adding a device in a slot with DDW
On Thu, Dec 27, 2012 at 02:34:00PM -0200, Thadeu Lima de Souza Cascardo wrote:
>The DDW code uses a eeh_dev struct from the pci_dev. However, this is
>not set until eeh_add_device_late is called.
>
>Since pci_bus_add_devices is called before eeh_add_device_late, the PCI
>devices are added to the bus, making drivers' probe hooks to be called.
>These will call set_dma_mask, which will call the DDW code, which will
>require the eeh_dev struct from pci_dev. This would result in a crash,
>due to a NULL dereference.
>
>Calling eeh_add_device_late after pci_bus_add_devices would make the
>system BUG, because device files shouldn't be added to devices there
>were not added to the system. So, a new function is needed to add such
>files only after pci_bus_add_devices have been called.
>
Could you please explain for a bit how did you trigger the problem? I'm
not sure you got it while doing PCI hotplug or just saw the issue during
system bootup stage :-)
>Cc: sta...@vger.kernel.org
>Signed-off-by: Thadeu Lima de Souza Cascardo
>---
> arch/powerpc/include/asm/eeh.h |3 +++
> arch/powerpc/kernel/pci-common.c |7 +--
> arch/powerpc/platforms/pseries/eeh.c | 24 +++-
> 3 files changed, 31 insertions(+), 3 deletions(-)
>
>diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
>index b0ef738..71aac19 100644
>--- a/arch/powerpc/include/asm/eeh.h
>+++ b/arch/powerpc/include/asm/eeh.h
>@@ -201,6 +201,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev);
> void __init eeh_addr_cache_build(void);
> void eeh_add_device_tree_early(struct device_node *);
> void eeh_add_device_tree_late(struct pci_bus *);
>+void eeh_add_device_tree_files(struct pci_bus *);
Since the function is going to add EEH specific sysfs files, its name would
be something like "eeh_add_sysfs_files" instead of "eeh_add_device_tree_files"
:-)
> void eeh_remove_bus_device(struct pci_dev *, int);
>
> /**
>@@ -240,6 +241,8 @@ static inline void eeh_add_device_tree_early(struct
>device_node *dn) { }
>
> static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
>
>+static inline void eeh_add_device_tree_files(struct pci_bus *bus) { }
>+
It'd better to rename the function name to "eeh_add_sysfs_files" mentioned
as above.
> static inline void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe) {
> }
>
> static inline void eeh_lock(void) { }
>diff --git a/arch/powerpc/kernel/pci-common.c
>b/arch/powerpc/kernel/pci-common.c
>index 7f94f76..7b1f14c 100644
>--- a/arch/powerpc/kernel/pci-common.c
>+++ b/arch/powerpc/kernel/pci-common.c
>@@ -1480,11 +1480,14 @@ void pcibios_finish_adding_to_bus(struct pci_bus *bus)
> pcibios_allocate_bus_resources(bus);
> pcibios_claim_one_bus(bus);
>
>+ /* Fixup EEH */
>+ eeh_add_device_tree_late(bus);
>+
> /* Add new devices to global lists. Register in proc, sysfs. */
> pci_bus_add_devices(bus);
>
>- /* Fixup EEH */
>- eeh_add_device_tree_late(bus);
>+ /* Add EEH sysfs files */
>+ eeh_add_device_tree_files(bus);
The function name would be "eeh_add_sysfs_files" as above.
> }
> EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
>
By the way, arch/powerpc/kernel/of_platform.c::of_pci_phb_probe is also calling
to eeh_add_device_tree_late() as well. Since you have removed part of the logic
from original eeh_add_device_tree_late(), which is add EEH specific sysfs files,
and you put that part of logic to eeh_add_device_tree_files(). So I think you
also need make the similiar change for of_pci_phb_probe() as well :-)
>diff --git a/arch/powerpc/platforms/pseries/eeh.c
>b/arch/powerpc/platforms/pseries/eeh.c
>index 9a04322..a667a34 100644
>--- a/arch/powerpc/platforms/pseries/eeh.c
>+++ b/arch/powerpc/platforms/pseries/eeh.c
>@@ -788,7 +788,6 @@ static void eeh_add_device_late(struct pci_dev *dev)
> dev->dev.archdata.edev = edev;
>
> eeh_addr_cache_insert_dev(dev);
>- eeh_sysfs_add_device(dev);
> }
>
> /**
>@@ -815,6 +814,29 @@ void eeh_add_device_tree_late(struct pci_bus *bus)
> EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
>
> /**
>+ * eeh_add_device_tree_files - Add EEH sysfs files for the indicated PCI bus
>+ * @bus: PCI bus
>+ *
>+ * This routine must be used to add EEH sysfs files for PCI
>+ * devices which are attached to the indicated PCI bus. The PCI bus
>+ * is added after system boot through hotplug or dlpar.
>+ */
>+void eeh_add_device_tree_files(struct pci_bus *bus)
>+{
>+ struct pci_dev *dev;
>+
>+ list_for_each_entry(dev, &bus->devices, bus_list) {
>+ eeh_sysfs_add_device(dev);
>+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
>+ struct pci_bus *subbus = dev->subordinate;
>+ if (subbus)
>+ eeh_add_device_tree_files(subbus);
>+ }
>+ }
>+}
>+EXPORT_SYMBOL_GPL(eeh_add_device_tree_files);
>+
The function name mentioned as above.
>+/**
> * eeh_remove_de
[PATCH] ppc/EEH: fix crash when adding a device in a slot with DDW
The DDW code uses a eeh_dev struct from the pci_dev. However, this is
not set until eeh_add_device_late is called.
Since pci_bus_add_devices is called before eeh_add_device_late, the PCI
devices are added to the bus, making drivers' probe hooks to be called.
These will call set_dma_mask, which will call the DDW code, which will
require the eeh_dev struct from pci_dev. This would result in a crash,
due to a NULL dereference.
Calling eeh_add_device_late after pci_bus_add_devices would make the
system BUG, because device files shouldn't be added to devices there
were not added to the system. So, a new function is needed to add such
files only after pci_bus_add_devices have been called.
Cc: sta...@vger.kernel.org
Signed-off-by: Thadeu Lima de Souza Cascardo
---
arch/powerpc/include/asm/eeh.h |3 +++
arch/powerpc/kernel/pci-common.c |7 +--
arch/powerpc/platforms/pseries/eeh.c | 24 +++-
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/eeh.h b/arch/powerpc/include/asm/eeh.h
index b0ef738..71aac19 100644
--- a/arch/powerpc/include/asm/eeh.h
+++ b/arch/powerpc/include/asm/eeh.h
@@ -201,6 +201,7 @@ int eeh_dev_check_failure(struct eeh_dev *edev);
void __init eeh_addr_cache_build(void);
void eeh_add_device_tree_early(struct device_node *);
void eeh_add_device_tree_late(struct pci_bus *);
+void eeh_add_device_tree_files(struct pci_bus *);
void eeh_remove_bus_device(struct pci_dev *, int);
/**
@@ -240,6 +241,8 @@ static inline void eeh_add_device_tree_early(struct
device_node *dn) { }
static inline void eeh_add_device_tree_late(struct pci_bus *bus) { }
+static inline void eeh_add_device_tree_files(struct pci_bus *bus) { }
+
static inline void eeh_remove_bus_device(struct pci_dev *dev, int purge_pe) { }
static inline void eeh_lock(void) { }
diff --git a/arch/powerpc/kernel/pci-common.c b/arch/powerpc/kernel/pci-common.c
index 7f94f76..7b1f14c 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1480,11 +1480,14 @@ void pcibios_finish_adding_to_bus(struct pci_bus *bus)
pcibios_allocate_bus_resources(bus);
pcibios_claim_one_bus(bus);
+ /* Fixup EEH */
+ eeh_add_device_tree_late(bus);
+
/* Add new devices to global lists. Register in proc, sysfs. */
pci_bus_add_devices(bus);
- /* Fixup EEH */
- eeh_add_device_tree_late(bus);
+ /* Add EEH sysfs files */
+ eeh_add_device_tree_files(bus);
}
EXPORT_SYMBOL_GPL(pcibios_finish_adding_to_bus);
diff --git a/arch/powerpc/platforms/pseries/eeh.c
b/arch/powerpc/platforms/pseries/eeh.c
index 9a04322..a667a34 100644
--- a/arch/powerpc/platforms/pseries/eeh.c
+++ b/arch/powerpc/platforms/pseries/eeh.c
@@ -788,7 +788,6 @@ static void eeh_add_device_late(struct pci_dev *dev)
dev->dev.archdata.edev = edev;
eeh_addr_cache_insert_dev(dev);
- eeh_sysfs_add_device(dev);
}
/**
@@ -815,6 +814,29 @@ void eeh_add_device_tree_late(struct pci_bus *bus)
EXPORT_SYMBOL_GPL(eeh_add_device_tree_late);
/**
+ * eeh_add_device_tree_files - Add EEH sysfs files for the indicated PCI bus
+ * @bus: PCI bus
+ *
+ * This routine must be used to add EEH sysfs files for PCI
+ * devices which are attached to the indicated PCI bus. The PCI bus
+ * is added after system boot through hotplug or dlpar.
+ */
+void eeh_add_device_tree_files(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ eeh_sysfs_add_device(dev);
+ if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
+ struct pci_bus *subbus = dev->subordinate;
+ if (subbus)
+ eeh_add_device_tree_files(subbus);
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(eeh_add_device_tree_files);
+
+/**
* eeh_remove_device - Undo EEH setup for the indicated pci device
* @dev: pci device to be removed
* @purge_pe: remove the PE or not
--
1.7.1
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