[PATCH 4/9] xen/smp: Don't leak interrupt name when offlining.

From: Konrad Rzeszutek Wilk
Date: Wed Jun 05 2013 - 11:57:11 EST


When the user does:
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 1 > /sys/devices/system/cpu/cpu1/online

kmemleak reports:
kmemleak: 7 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

unreferenced object 0xffff88003fa51240 (size 32):
comm "swapper/0", pid 1, jiffies 4294667339 (age 1027.789s)
hex dump (first 32 bytes):
72 65 73 63 68 65 64 31 00 00 00 00 00 00 00 00 resched1........
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff81660721>] kmemleak_alloc+0x21/0x50
[<ffffffff81190aac>] __kmalloc_track_caller+0xec/0x2a0
[<ffffffff812fe1bb>] kvasprintf+0x5b/0x90
[<ffffffff812fe228>] kasprintf+0x38/0x40
[<ffffffff81047ed1>] xen_smp_intr_init+0x41/0x2c0
[<ffffffff816636d3>] xen_cpu_up+0x393/0x3e8
[<ffffffff8166bbf5>] _cpu_up+0xd1/0x14b
[<ffffffff8166bd48>] cpu_up+0xd9/0xec
[<ffffffff81ae6e4a>] smp_init+0x4b/0xa3
[<ffffffff81ac4981>] kernel_init_freeable+0xdb/0x1e6
[<ffffffff8165ce39>] kernel_init+0x9/0xf0
[<ffffffff8167edfc>] ret_from_fork+0x7c/0xb0
[<ffffffffffffffff>] 0xffffffffffffffff

This patch fixes some of it by using the 'struct xen_common_irq->name'
field to stash away the char so that it can be freed when
the interrupt line is destroyed.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
arch/x86/xen/smp.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 6a483cd..37fbe71 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -107,19 +107,27 @@ static void xen_smp_intr_free(unsigned int cpu)
if (per_cpu(xen_resched_irq, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL);
per_cpu(xen_resched_irq, cpu).irq = -1;
+ kfree(per_cpu(xen_resched_irq, cpu).name);
+ per_cpu(xen_resched_irq, cpu).name = NULL;
}
if (per_cpu(xen_callfunc_irq, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_callfunc_irq, cpu).irq, NULL);
per_cpu(xen_callfunc_irq, cpu).irq = -1;
+ kfree(per_cpu(xen_callfunc_irq, cpu).name);
+ per_cpu(xen_callfunc_irq, cpu).name = NULL;
}
if (per_cpu(xen_debug_irq, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_debug_irq, cpu).irq, NULL);
per_cpu(xen_debug_irq, cpu).irq = -1;
+ kfree(per_cpu(xen_debug_irq, cpu).name);
+ per_cpu(xen_debug_irq, cpu).name = NULL;
}
if (per_cpu(xen_callfuncsingle_irq, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_callfuncsingle_irq, cpu).irq,
NULL);
per_cpu(xen_callfuncsingle_irq, cpu).irq = -1;
+ kfree(per_cpu(xen_callfuncsingle_irq, cpu).name);
+ per_cpu(xen_callfuncsingle_irq, cpu).name = NULL;
}
if (xen_hvm_domain())
return;
@@ -127,12 +135,14 @@ static void xen_smp_intr_free(unsigned int cpu)
if (per_cpu(xen_irq_work, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);
per_cpu(xen_irq_work, cpu).irq = -1;
+ kfree(per_cpu(xen_irq_work, cpu).name);
+ per_cpu(xen_irq_work, cpu).name = NULL;
}
};
static int xen_smp_intr_init(unsigned int cpu)
{
int rc;
- const char *resched_name, *callfunc_name, *debug_name;
+ char *resched_name, *callfunc_name, *debug_name;

resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
@@ -144,6 +154,7 @@ static int xen_smp_intr_init(unsigned int cpu)
if (rc < 0)
goto fail;
per_cpu(xen_resched_irq, cpu).irq = rc;
+ per_cpu(xen_resched_irq, cpu).name = resched_name;

callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
@@ -155,6 +166,7 @@ static int xen_smp_intr_init(unsigned int cpu)
if (rc < 0)
goto fail;
per_cpu(xen_callfunc_irq, cpu).irq = rc;
+ per_cpu(xen_callfunc_irq, cpu).name = callfunc_name;

debug_name = kasprintf(GFP_KERNEL, "debug%d", cpu);
rc = bind_virq_to_irqhandler(VIRQ_DEBUG, cpu, xen_debug_interrupt,
@@ -163,6 +175,7 @@ static int xen_smp_intr_init(unsigned int cpu)
if (rc < 0)
goto fail;
per_cpu(xen_debug_irq, cpu).irq = rc;
+ per_cpu(xen_debug_irq, cpu).name = debug_name;

callfunc_name = kasprintf(GFP_KERNEL, "callfuncsingle%d", cpu);
rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_SINGLE_VECTOR,
@@ -174,6 +187,7 @@ static int xen_smp_intr_init(unsigned int cpu)
if (rc < 0)
goto fail;
per_cpu(xen_callfuncsingle_irq, cpu).irq = rc;
+ per_cpu(xen_callfuncsingle_irq, cpu).name = callfunc_name;

/*
* The IRQ worker on PVHVM goes through the native path and uses the
@@ -192,6 +206,7 @@ static int xen_smp_intr_init(unsigned int cpu)
if (rc < 0)
goto fail;
per_cpu(xen_irq_work, cpu).irq = rc;
+ per_cpu(xen_irq_work, cpu).name = callfunc_name;

return 0;

--
1.8.1.4

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