x86: io-apic - interrupt remapping fix

Interrupt remapping could lead to NULL dereference in case of
kzalloc failed and memory leak in other way. So fix the
both cases.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 17 insertions, 2 deletions

diff --git a/arch/x86/kernel/io_apic.c b/arch/x86/kernel/io_apic.c
index 01419fdc1d5d..4cc9cb64c811 100644
--- a/arch/x86/kernel/io_apic.c
+++ b/arch/x86/kernel/io_apic.c
@@ -812,7 +812,7 @@ int save_mask_IO_APIC_setup(void)
                         kzalloc(sizeof(struct IO_APIC_route_entry) *
                                 nr_ioapic_registers[apic], GFP_KERNEL);
                 if (!early_ioapic_entries[apic])
-                        return -ENOMEM;
+                        goto nomem;
         }
 
         for (apic = 0; apic < nr_ioapics; apic++)
@@ -826,17 +826,32 @@ int save_mask_IO_APIC_setup(void)
                                 ioapic_write_entry(apic, pin, entry);
                         }
                 }
+
         return 0;
+
+nomem:
+        for (; apic > 0; apic--)
+                kfree(early_ioapic_entries[apic]);
+        kfree(early_ioapic_entries[apic]);
+        memset(early_ioapic_entries, 0,
+                ARRAY_SIZE(early_ioapic_entries));
+
+        return -ENOMEM;
 }
 
 void restore_IO_APIC_setup(void)
 {
         int apic, pin;
 
-        for (apic = 0; apic < nr_ioapics; apic++)
+        for (apic = 0; apic < nr_ioapics; apic++) {
+                if (!early_ioapic_entries[apic])
+                        break;
                 for (pin = 0; pin < nr_ioapic_registers[apic]; pin++)
                         ioapic_write_entry(apic, pin,
                                            early_ioapic_entries[apic][pin]);
+                kfree(early_ioapic_entries[apic]);
+                early_ioapic_entries[apic] = NULL;
+        }
 }
 
 void reinit_intr_remapped_IO_APIC(int intr_remapping)