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PCI: pnv_php: Clean up allocated IRQs on unplug

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[ Upstream commit 4668619092554e1b95c9a5ac2941ca47ba6d548a ]

When the root of a nested PCIe bridge configuration is unplugged, the
pnv_php driver leaked the allocated IRQ resources for the child bridges'
hotplug event notifications, resulting in a panic.

Fix this by walking all child buses and deallocating all its IRQ resources
before calling pci_hp_remove_devices().

Also modify the lifetime of the workqueue at struct pnv_php_slot::wq so
that it is only destroyed in pnv_php_free_slot(), instead of
pnv_php_disable_irq(). This is required since pnv_php_disable_irq() will
now be called by workers triggered by hot unplug interrupts, so the
workqueue needs to stay allocated.

The abridged kernel panic that occurs without this patch is as follows:

  WARNING: CPU: 0 PID: 687 at kernel/irq/msi.c:292 msi_device_data_release+0x6c/0x9c
  CPU: 0 UID: 0 PID: 687 Comm: bash Not tainted 6.14.0-rc5+ #2
  Call Trace:
   msi_device_data_release+0x34/0x9c (unreliable)
   release_nodes+0x64/0x13c
   devres_release_all+0xc0/0x140
   device_del+0x2d4/0x46c
   pci_destroy_dev+0x5c/0x194
   pci_hp_remove_devices+0x90/0x128
   pci_hp_remove_devices+0x44/0x128
   pnv_php_disable_slot+0x54/0xd4
   power_write_file+0xf8/0x18c
   pci_slot_attr_store+0x40/0x5c
   sysfs_kf_write+0x64/0x78
   kernfs_fop_write_iter+0x1b0/0x290
   vfs_write+0x3bc/0x50c
   ksys_write+0x84/0x140
   system_call_exception+0x124/0x230
   system_call_vectored_common+0x15c/0x2ec

Signed-off-by: Shawn Anastasio <sanastasio@raptorengineering.com>
Signed-off-by: Timothy Pearson <tpearson@raptorengineering.com>
[bhelgaas: tidy comments]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/2013845045.1359852.1752615367790.JavaMail.zimbra@raptorengineeringinc.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Timothy Pearson
2025-07-15 16:36:07 -05:00
committed by Greg Kroah-Hartman
parent 0842b64382
commit 8c1ad4af16
1 changed files with 78 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

98
drivers/pci/hotplug/pnv_php.c
View File

@@ -3,6 +3,7 @@
* PCI Hotplug Driver for PowerPC PowerNV platform.
*
* Copyright Gavin Shan, IBM Corporation 2016.
* Copyright (C) 2025 Raptor Engineering, LLC
*/
#include <linux/libfdt.h>
@@ -34,8 +35,10 @@ static void pnv_php_register(struct device_node *dn);
static void pnv_php_unregister_one(struct device_node *dn);
static void pnv_php_unregister(struct device_node *dn);
static void pnv_php_enable_irq(struct pnv_php_slot *php_slot);
static void pnv_php_disable_irq(struct pnv_php_slot *php_slot,
bool disable_device)
bool disable_device, bool disable_msi)
{
struct pci_dev *pdev = php_slot->pdev;
u16 ctrl;
@@ -51,19 +54,15 @@ static void pnv_php_disable_irq(struct pnv_php_slot *php_slot,
php_slot->irq = 0;
}
if (php_slot->wq) {
destroy_workqueue(php_slot->wq);
php_slot->wq = NULL;
}
if (disable_device) {
if (disable_device || disable_msi) {
if (pdev->msix_enabled)
pci_disable_msix(pdev);
else if (pdev->msi_enabled)
pci_disable_msi(pdev);
pci_disable_device(pdev);
}
if (disable_device)
pci_disable_device(pdev);
}
static void pnv_php_free_slot(struct kref *kref)
@@ -72,7 +71,8 @@ static void pnv_php_free_slot(struct kref *kref)
struct pnv_php_slot, kref);
WARN_ON(!list_empty(&php_slot->children));
pnv_php_disable_irq(php_slot, false);
pnv_php_disable_irq(php_slot, false, false);
destroy_workqueue(php_slot->wq);
kfree(php_slot->name);
kfree(php_slot);
}
@@ -559,8 +559,58 @@ static int pnv_php_reset_slot(struct hotplug_slot *slot, int probe)
static int pnv_php_enable_slot(struct hotplug_slot *slot)
{
struct pnv_php_slot *php_slot = to_pnv_php_slot(slot);
u32 prop32;
int ret;
return pnv_php_enable(php_slot, true);
ret = pnv_php_enable(php_slot, true);
if (ret)
return ret;
/* (Re-)enable interrupt if the slot supports surprise hotplug */
ret = of_property_read_u32(php_slot->dn, "ibm,slot-surprise-pluggable",
&prop32);
if (!ret && prop32)
pnv_php_enable_irq(php_slot);
return 0;
}
/*
* Disable any hotplug interrupts for all slots on the provided bus, as well as
* all downstream slots in preparation for a hot unplug.
*/
static int pnv_php_disable_all_irqs(struct pci_bus *bus)
{
struct pci_bus *child_bus;
struct pci_slot *slot;
/* First go down child buses */
list_for_each_entry(child_bus, &bus->children, node)
pnv_php_disable_all_irqs(child_bus);
/* Disable IRQs for all pnv_php slots on this bus */
list_for_each_entry(slot, &bus->slots, list) {
struct pnv_php_slot *php_slot = to_pnv_php_slot(slot->hotplug);
pnv_php_disable_irq(php_slot, false, true);
}
return 0;
}
/*
* Disable any hotplug interrupts for all downstream slots on the provided
* bus in preparation for a hot unplug.
*/
static int pnv_php_disable_all_downstream_irqs(struct pci_bus *bus)
{
struct pci_bus *child_bus;
/* Go down child buses, recursively deactivating their IRQs */
list_for_each_entry(child_bus, &bus->children, node)
pnv_php_disable_all_irqs(child_bus);
return 0;
}
static int pnv_php_disable_slot(struct hotplug_slot *slot)
@@ -577,6 +627,13 @@ static int pnv_php_disable_slot(struct hotplug_slot *slot)
php_slot->state != PNV_PHP_STATE_REGISTERED)
return 0;
/*
* Free all IRQ resources from all child slots before remove.
* Note that we do not disable the root slot IRQ here as that
* would also deactivate the slot hot (re)plug interrupt!
*/
pnv_php_disable_all_downstream_irqs(php_slot->bus);
/* Remove all devices behind the slot */
pci_lock_rescan_remove();
pci_hp_remove_devices(php_slot->bus);
@@ -645,6 +702,15 @@ static struct pnv_php_slot *pnv_php_alloc_slot(struct device_node *dn)
return NULL;
}
/* Allocate workqueue for this slot's interrupt handling */
php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name);
if (!php_slot->wq) {
SLOT_WARN(php_slot, "Cannot alloc workqueue\n");
kfree(php_slot->name);
kfree(php_slot);
return NULL;
}
if (dn->child && PCI_DN(dn->child))
php_slot->slot_no = PCI_SLOT(PCI_DN(dn->child)->devfn);
else
@@ -841,14 +907,6 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq)
u16 sts, ctrl;
int ret;
/* Allocate workqueue */
php_slot->wq = alloc_workqueue("pciehp-%s", 0, 0, php_slot->name);
if (!php_slot->wq) {
SLOT_WARN(php_slot, "Cannot alloc workqueue\n");
pnv_php_disable_irq(php_slot, true);
return;
}
/* Check PDC (Presence Detection Change) is broken or not */
ret = of_property_read_u32(php_slot->dn, "ibm,slot-broken-pdc",
&broken_pdc);
@@ -867,7 +925,7 @@ static void pnv_php_init_irq(struct pnv_php_slot *php_slot, int irq)
ret = request_irq(irq, pnv_php_interrupt, IRQF_SHARED,
php_slot->name, php_slot);
if (ret) {
pnv_php_disable_irq(php_slot, true);
pnv_php_disable_irq(php_slot, true, true);
SLOT_WARN(php_slot, "Error %d enabling IRQ %d\n", ret, irq);
return;
}