[PATCH AUTOSEL 4.4 29/56] x86/PCI: Fix PCI IRQ routing table memory leak

Sasha Levin
2019-06-01T13:29:35Z

From: Wenwen Wang <wang6495@umn.edu>

[ Upstream commit ea094d53580f40c2124cef3d072b73b2425e7bfd ]

In pcibios_irq_init(), the PCI IRQ routing table 'pirq_table' is first
found through pirq_find_routing_table(). If the table is not found and
CONFIG_PCI_BIOS is defined, the table is then allocated in
pcibios_get_irq_routing_table() using kmalloc(). Later, if the I/O APIC is
used, this table is actually not used. In that case, the allocated table
is not freed, which is a memory leak.

Free the allocated table if it is not used.

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
[bhelgaas: added Ingo's reviewed-by, since the only change since v1 was to
use the irq_routing_table local variable name he suggested]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/pci/irq.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index 9bd1154847457..5f0e596b0519b 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -1117,6 +1117,8 @@ static struct dmi_system_id __initdata pciirq_dmi_table[] = {

void __init pcibios_irq_init(void)
{
+ struct irq_routing_table *rtable = NULL;
+
DBG(KERN_DEBUG "PCI: IRQ init\n");

if (raw_pci_ops == NULL)
@@ -1127,8 +1129,10 @@ void __init pcibios_irq_init(void)
pirq_table = pirq_find_routing_table();

#ifdef CONFIG_PCI_BIOS
- if (!pirq_table && (pci_probe & PCI_BIOS_IRQ_SCAN))
+ if (!pirq_table && (pci_probe & PCI_BIOS_IRQ_SCAN)) {
pirq_table = pcibios_get_irq_routing_table();
+ rtable = pirq_table;
+ }
#endif
if (pirq_table) {
pirq_peer_trick();
@@ -1143,8 +1147,10 @@ void __init pcibios_irq_init(void)
* If we're using the I/O APIC, avoid using the PCI IRQ
* routing table
*/
- if (io_apic_assign_pci_irqs)
+ if (io_apic_assign_pci_irqs) {
+ kfree(rtable);
pirq_table = NULL;
+ }
}

x86_init.pci.fixup_irqs();
--
2.20.1