| Message ID | 20190430155229.14213-1-pierre-louis.bossart@linux.intel.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | ACPI / property: fix handling of data_nodes in acpi_get_next_subnode() | expand |
On Tue, Apr 30, 2019 at 10:52:29AM -0500, Pierre-Louis Bossart wrote: > When the DSDT tables expose devices with subdevices and a set of > hierarchical _DSD properties, the data returned by > acpi_get_next_subnode() is incorrect, with the results suggesting a bad > pointer assignment. The parser works fine with device_nodes or > data_nodes, but not with a combination of the two. > > The problem is traced to an invalid pointer used when jumping from > handling device_nodes to data nodes. The existing code looks for data > nodes below the last subdevice found instead of the common root. Fix > by forcing the acpi_device pointer to be derived from the same fwnode > for the two types of subnodes. > > This same problem of handling device and data nodes was already fixed > in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data > node parsing in acpi_get_next_subnode()")' but broken later by 'commit > 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so > this should probably go to linux-stable all the way to 4.12 Period is missed in above sentence. I think it make sense to add Fixes: tag. Nevertheless, Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Thank you for fixing this interesting issue! > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> > --- > drivers/acpi/property.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c > index 5815356ea6ad..efc74f912f39 100644 > --- a/drivers/acpi/property.c > +++ b/drivers/acpi/property.c > @@ -943,6 +943,16 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, > const struct acpi_data_node *data = to_acpi_data_node(fwnode); > struct acpi_data_node *dn; > > + /* > + * We can have a combination of device and data nodes, > + * e.g. with hierarchical _DSD properties. Make sure > + * the adev pointer is restored before going through > + * data nodes, otherwise we will be looking for > + * data_nodes below the last device found instead of > + * the common fwnode shared by device_nodes and > + * data_nodes > + */ > + adev = to_acpi_device_node(fwnode); > if (adev) > head = &adev->data.subnodes; > else if (data) > -- > 2.17.1 >
On 4/30/19 11:30 AM, Andy Shevchenko wrote: > On Tue, Apr 30, 2019 at 10:52:29AM -0500, Pierre-Louis Bossart wrote: >> When the DSDT tables expose devices with subdevices and a set of >> hierarchical _DSD properties, the data returned by >> acpi_get_next_subnode() is incorrect, with the results suggesting a bad >> pointer assignment. The parser works fine with device_nodes or >> data_nodes, but not with a combination of the two. >> >> The problem is traced to an invalid pointer used when jumping from >> handling device_nodes to data nodes. The existing code looks for data >> nodes below the last subdevice found instead of the common root. Fix >> by forcing the acpi_device pointer to be derived from the same fwnode >> for the two types of subnodes. >> >> This same problem of handling device and data nodes was already fixed >> in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data >> node parsing in acpi_get_next_subnode()")' but broken later by 'commit >> 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so >> this should probably go to linux-stable all the way to 4.12 > > Period is missed in above sentence. > > I think it make sense to add Fixes: tag. Thanks Andy for the review. I hesitated to add a fixes tag. The line about resetting the adev pointer was indeed removed in the latter commit, but there were a slew of other changes done later by Sakari on hierarchical _DSD so it's quite complicated to say when this was last fully functional. > > Nevertheless, > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > Thank you for fixing this interesting issue! > >> >> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> >> --- >> drivers/acpi/property.c | 10 ++++++++++ >> 1 file changed, 10 insertions(+) >> >> diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c >> index 5815356ea6ad..efc74f912f39 100644 >> --- a/drivers/acpi/property.c >> +++ b/drivers/acpi/property.c >> @@ -943,6 +943,16 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, >> const struct acpi_data_node *data = to_acpi_data_node(fwnode); >> struct acpi_data_node *dn; >> >> + /* >> + * We can have a combination of device and data nodes, >> + * e.g. with hierarchical _DSD properties. Make sure >> + * the adev pointer is restored before going through >> + * data nodes, otherwise we will be looking for >> + * data_nodes below the last device found instead of >> + * the common fwnode shared by device_nodes and >> + * data_nodes >> + */ >> + adev = to_acpi_device_node(fwnode); >> if (adev) >> head = &adev->data.subnodes; >> else if (data) >> -- >> 2.17.1 >> >
On Tue, Apr 30, 2019 at 11:41:50AM -0500, Pierre-Louis Bossart wrote: > On 4/30/19 11:30 AM, Andy Shevchenko wrote: > > On Tue, Apr 30, 2019 at 10:52:29AM -0500, Pierre-Louis Bossart wrote: > > > When the DSDT tables expose devices with subdevices and a set of > > > hierarchical _DSD properties, the data returned by > > > acpi_get_next_subnode() is incorrect, with the results suggesting a bad > > > pointer assignment. The parser works fine with device_nodes or > > > data_nodes, but not with a combination of the two. > > > > > > The problem is traced to an invalid pointer used when jumping from > > > handling device_nodes to data nodes. The existing code looks for data > > > nodes below the last subdevice found instead of the common root. Fix > > > by forcing the acpi_device pointer to be derived from the same fwnode > > > for the two types of subnodes. > > > > > > This same problem of handling device and data nodes was already fixed > > > in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data > > > node parsing in acpi_get_next_subnode()")' but broken later by 'commit > > > 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so > > > this should probably go to linux-stable all the way to 4.12 > > > > Period is missed in above sentence. > > > > I think it make sense to add Fixes: tag. > > Thanks Andy for the review. I hesitated to add a fixes tag. The line about > resetting the adev pointer was indeed removed in the latter commit, but > there were a slew of other changes done later by Sakari on hierarchical _DSD > so it's quite complicated to say when this was last fully functional. I see, btw, you forgot to add Sakari to Cc list, he is doing a lot lately WRT device properties. > > Nevertheless, > > Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > > > > Thank you for fixing this interesting issue!
On Tue, Apr 30, 2019 at 5:52 PM Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> wrote: > > When the DSDT tables expose devices with subdevices and a set of > hierarchical _DSD properties, the data returned by > acpi_get_next_subnode() is incorrect, with the results suggesting a bad > pointer assignment. The parser works fine with device_nodes or > data_nodes, but not with a combination of the two. > > The problem is traced to an invalid pointer used when jumping from > handling device_nodes to data nodes. The existing code looks for data > nodes below the last subdevice found instead of the common root. Fix > by forcing the acpi_device pointer to be derived from the same fwnode > for the two types of subnodes. > > This same problem of handling device and data nodes was already fixed > in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data > node parsing in acpi_get_next_subnode()")' but broken later by 'commit > 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so > this should probably go to linux-stable all the way to 4.12 > > Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Applied with the Andy's R-by, but I reformatted the comment to take fewer lines of code. Thanks!
diff --git a/drivers/acpi/property.c b/drivers/acpi/property.c index 5815356ea6ad..efc74f912f39 100644 --- a/drivers/acpi/property.c +++ b/drivers/acpi/property.c @@ -943,6 +943,16 @@ struct fwnode_handle *acpi_get_next_subnode(const struct fwnode_handle *fwnode, const struct acpi_data_node *data = to_acpi_data_node(fwnode); struct acpi_data_node *dn; + /* + * We can have a combination of device and data nodes, + * e.g. with hierarchical _DSD properties. Make sure + * the adev pointer is restored before going through + * data nodes, otherwise we will be looking for + * data_nodes below the last device found instead of + * the common fwnode shared by device_nodes and + * data_nodes + */ + adev = to_acpi_device_node(fwnode); if (adev) head = &adev->data.subnodes; else if (data)
When the DSDT tables expose devices with subdevices and a set of hierarchical _DSD properties, the data returned by acpi_get_next_subnode() is incorrect, with the results suggesting a bad pointer assignment. The parser works fine with device_nodes or data_nodes, but not with a combination of the two. The problem is traced to an invalid pointer used when jumping from handling device_nodes to data nodes. The existing code looks for data nodes below the last subdevice found instead of the common root. Fix by forcing the acpi_device pointer to be derived from the same fwnode for the two types of subnodes. This same problem of handling device and data nodes was already fixed in a similar way by 'commit bf4703fdd166 ("ACPI / property: fix data node parsing in acpi_get_next_subnode()")' but broken later by 'commit 34055190b19 ("ACPI / property: Add fwnode_get_next_child_node()")', so this should probably go to linux-stable all the way to 4.12 Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> --- drivers/acpi/property.c | 10 ++++++++++ 1 file changed, 10 insertions(+)