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From: Wenwen Wang <wang6495@umn.edu>
To: Wenwen Wang <wang6495@umn.edu>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	x86@kernel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
	linux-pci@vger.kernel.org (open list:PCI SUBSYSTEM),
	linux-kernel@vger.kernel.org (open list:X86 ARCHITECTURE (32-BIT
	AND 64-BIT))
Subject: [PATCH v2] x86/PCI: fix a memory leak bug
Date: Tue, 16 Apr 2019 09:01:38 -0500	[thread overview]
Message-ID: <1555423298-6677-1-git-send-email-wang6495@umn.edu> (raw)

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


             reply	other threads:[~2019-04-16 14:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-16 14:01 Wenwen Wang [this message]
2019-04-16 19:58 ` [PATCH v2] x86/PCI: fix a memory leak bug Thomas Gleixner
2019-04-16 21:29   ` Wenwen Wang
2019-04-17  5:58     ` Ingo Molnar
2019-04-17 14:10       ` Wenwen Wang

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