From: Rafael J. Wysocki <[email protected]>
If acpi_pci_find_companion() is called for a device whose parent
pointer is NULL, it will crash when attempting to get the ACPI
companion of the parent due to a NULL pointer dereference in
the ACPI_COMPANION() macro.
This was not a problem before commit 375553a93201 ("PCI: Setup ACPI
fwnode early and at the same time with OF") that made pci_setup_device()
call pci_set_acpi_fwnode() and so it allowed devices with NULL parent
pointers to be passed to acpi_pci_find_companion() which is the case
in pci_iov_add_virtfn(), for instance.
Fix this issue by making acpi_pci_find_companion() check the device's
parent pointer upfront and bail out if it is NULL.
While pci_iov_add_virtfn() can be changed to set the device's parent
pointer before calling pci_setup_device() for it, checking pointers
against NULL before dereferencing them is prudent anyway and looking
for ACPI companions of virtual functions isn't really useful.
Fixes: 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF")
Link: https://lore.kernel.org/linux-acpi/[email protected]/
Reported-by: Niklas Schnelle <[email protected]>
Tested-by: Niklas Schnelle <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
---
drivers/pci/pci-acpi.c | 3 +++
1 file changed, 3 insertions(+)
Index: linux-pm/drivers/pci/pci-acpi.c
===================================================================
--- linux-pm.orig/drivers/pci/pci-acpi.c
+++ linux-pm/drivers/pci/pci-acpi.c
@@ -1243,6 +1243,9 @@ static struct acpi_device *acpi_pci_find
bool check_children;
u64 addr;
+ if (!dev->parent)
+ return NULL;
+
down_read(&pci_acpi_companion_lookup_sem);
adev = pci_acpi_find_companion_hook ?
On Fri, Oct 1, 2021 at 3:58 PM Rafael J. Wysocki <[email protected]> wrote:
>
> From: Rafael J. Wysocki <[email protected]>
>
> If acpi_pci_find_companion() is called for a device whose parent
> pointer is NULL, it will crash when attempting to get the ACPI
> companion of the parent due to a NULL pointer dereference in
> the ACPI_COMPANION() macro.
>
> This was not a problem before commit 375553a93201 ("PCI: Setup ACPI
> fwnode early and at the same time with OF") that made pci_setup_device()
> call pci_set_acpi_fwnode() and so it allowed devices with NULL parent
> pointers to be passed to acpi_pci_find_companion() which is the case
> in pci_iov_add_virtfn(), for instance.
>
> Fix this issue by making acpi_pci_find_companion() check the device's
> parent pointer upfront and bail out if it is NULL.
>
> While pci_iov_add_virtfn() can be changed to set the device's parent
> pointer before calling pci_setup_device() for it, checking pointers
> against NULL before dereferencing them is prudent anyway and looking
> for ACPI companions of virtual functions isn't really useful.
>
> Fixes: 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF")
> Link: https://lore.kernel.org/linux-acpi/[email protected]/
> Reported-by: Niklas Schnelle <[email protected]>
> Tested-by: Niklas Schnelle <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
Due to the lack of negative feedback I'm queuing this up for 5.15-rc5.
If there are concerns, please let me know.
> ---
> drivers/pci/pci-acpi.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> Index: linux-pm/drivers/pci/pci-acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-acpi.c
> +++ linux-pm/drivers/pci/pci-acpi.c
> @@ -1243,6 +1243,9 @@ static struct acpi_device *acpi_pci_find
> bool check_children;
> u64 addr;
>
> + if (!dev->parent)
> + return NULL;
> +
> down_read(&pci_acpi_companion_lookup_sem);
>
> adev = pci_acpi_find_companion_hook ?
>
>
>
On Fri, Oct 01, 2021 at 03:58:10PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <[email protected]>
>
> If acpi_pci_find_companion() is called for a device whose parent
> pointer is NULL, it will crash when attempting to get the ACPI
> companion of the parent due to a NULL pointer dereference in
> the ACPI_COMPANION() macro.
>
> This was not a problem before commit 375553a93201 ("PCI: Setup ACPI
> fwnode early and at the same time with OF") that made pci_setup_device()
> call pci_set_acpi_fwnode() and so it allowed devices with NULL parent
> pointers to be passed to acpi_pci_find_companion() which is the case
> in pci_iov_add_virtfn(), for instance.
>
> Fix this issue by making acpi_pci_find_companion() check the device's
> parent pointer upfront and bail out if it is NULL.
>
> While pci_iov_add_virtfn() can be changed to set the device's parent
> pointer before calling pci_setup_device() for it, checking pointers
> against NULL before dereferencing them is prudent anyway and looking
> for ACPI companions of virtual functions isn't really useful.
>
> Fixes: 375553a93201 ("PCI: Setup ACPI fwnode early and at the same time with OF")
> Link: https://lore.kernel.org/linux-acpi/[email protected]/
> Reported-by: Niklas Schnelle <[email protected]>
> Tested-by: Niklas Schnelle <[email protected]>
> Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Bjorn Helgaas <[email protected]>
> ---
> drivers/pci/pci-acpi.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> Index: linux-pm/drivers/pci/pci-acpi.c
> ===================================================================
> --- linux-pm.orig/drivers/pci/pci-acpi.c
> +++ linux-pm/drivers/pci/pci-acpi.c
> @@ -1243,6 +1243,9 @@ static struct acpi_device *acpi_pci_find
> bool check_children;
> u64 addr;
>
> + if (!dev->parent)
> + return NULL;
> +
> down_read(&pci_acpi_companion_lookup_sem);
>
> adev = pci_acpi_find_companion_hook ?
>
>
>