x86: pda_init(): fix memory leak when using CPU hotplug

pda->irqstackptr is allocated whenever a CPU is set online.
But it is never freed. This results in a memory leak of 16K
for each CPU offline/online cycle.

Fix is to allocate pda->irqstackptr only once.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: akpm@linux-foundation.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/kernel/cpu/common_64.c b/arch/x86/kernel/cpu/common_64.c
index c3afba5a81a7bfb1780e715c153349de42106df2..4f2eeb5652eae634a4bf8c5ad01182c3141656e6 100644 (file)
--- a/arch/x86/kernel/cpu/common_64.c
+++ b/arch/x86/kernel/cpu/common_64.c
@@ -529,17 +529,20 @@ void pda_init(int cpu)
                /* others are initialized in smpboot.c */
                pda->pcurrent = &init_task;
                pda->irqstackptr = boot_cpu_stack;
+               pda->irqstackptr += IRQSTACKSIZE - 64;
        } else {
-               pda->irqstackptr = (char *)
-                       __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
-               if (!pda->irqstackptr)
-                       panic("cannot allocate irqstack for cpu %d", cpu);
+               if (!pda->irqstackptr) {
+                       pda->irqstackptr = (char *)
+                               __get_free_pages(GFP_ATOMIC, IRQSTACK_ORDER);
+                       if (!pda->irqstackptr)
+                               panic("cannot allocate irqstack for cpu %d",
+                                     cpu);
+                       pda->irqstackptr += IRQSTACKSIZE - 64;
+               }
 
                if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
                        pda->nodenumber = cpu_to_node(cpu);
        }
-
-       pda->irqstackptr += IRQSTACKSIZE-64;
 }
 
 char boot_exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ +