[Update][PATCH v4 2/3] PCI/ASPM: Fix NULL pointer when find parent pcie_link_state

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



https://bugzilla.kernel.org/show_bug.cgi?id=94361 reported
in ATCA platform, system had unusual pcie topology:

(root port)   (downstream port)   (upstream port)
+-1c.0-[02-0a]----00.0-[03-0a]--+-00.0-[04]--
|                               +-01.0-[05]-- (downstream port)
|                               +-02.0-[06]--
|                               +-03.0-[07]--
|                               +-08.0-[08]--
|                               +-09.0-[09]--
|                               \-0a.0-[0a]--
We assumed root port and downstream port always
have external link, and downstream port always has a
upstream port. So in this case, when we allocated
pcie_link_state for downstream port 02:00.0, it try
to get parent bus pcie_link_state,
parent = pdev->bus->parent->self->link_state;
because root bus self is NULL, system will crash here.

Use pdev->has_secondary_link(introduced in previous patch)
to fix this issue.

Signed-off-by: Yijing Wang <wangyijing@xxxxxxxxxx>
---
 drivers/pci/pcie/aspm.c |    9 ++++-----
 1 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 4e1af76..942bf97 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -525,7 +525,7 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
 	INIT_LIST_HEAD(&link->children);
 	INIT_LIST_HEAD(&link->link);
 	link->pdev = pdev;
-	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM) {
+	if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) {
 		struct pcie_link_state *parent;
 		parent = pdev->bus->parent->self->link_state;
 		if (!parent) {
@@ -561,8 +561,8 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
 
 	if (!pci_is_pcie(pdev) || pdev->link_state)
 		return;
-	if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT &&
-	    pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
+
+	if (!pdev->has_secondary_link)
 		return;
 
 	/* VIA has a strange chipset, root port is under a bridge */
@@ -715,8 +715,7 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
 	if (!pci_is_pcie(pdev))
 		return;
 
-	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
-	    pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM)
+	if (pdev->has_secondary_link)
 		parent = pdev;
 	if (!parent || !parent->link_state)
 		return;
-- 
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [DMA Engine]     [Linux Coverity]     [Linux USB]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [Greybus]

  Powered by Linux