[PATCH v2] x86/PCI: fix a memory leak bug

Wenwen Wang
2019-04-16T14:02:03Z

In pcibios_irq_init(), the PCI IRQ routing table 'pirq_table' is firstly
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(). In the following
execution, if the I/O APIC is used, this table is actually not used.
However, in that case, the allocated table is not freed, which can lead to
a memory leak bug.

To fix this issue, this patch frees the allocated table if it is not used.

Signed-off-by: Wenwen Wang <wang6495@umn.edu>
---
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 52e5510..d3a73f9 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -1119,6 +1119,8 @@ static const struct dmi_system_id pciirq_dmi_table[] __initconst = {

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

if (raw_pci_ops == NULL)
@@ -1129,8 +1131,10 @@ 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();
@@ -1145,8 +1149,10 @@ 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();
--
2.7.4