[PATCH 5/9] xen/spinlock: Don't leak interrupt name when offlining.
From: Konrad Rzeszutek Wilk
Date: Wed Jun 05 2013 - 11:55:10 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 0xffff88003fa51260 (size 32):
comm "swapper/0", pid 1, jiffies 4294667339 (age 1027.789s)
hex dump (first 32 bytes):
73 70 69 6e 6c 6f 63 6b 31 00 00 00 00 00 00 00 spinlock1.......
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
[<ffffffff81663789>] xen_init_lock_cpu+0x61/0xbe
[<ffffffff816633a6>] xen_cpu_up+0x66/0x3e8
[<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
Instead of doing it like the "xen/smp: Don't leak interrupt name when offlining"
patch did (which has a per-cpu structure which contains both the
IRQ number and char*) we use a per-cpu pointers to a *char.
The reason is that the "__this_cpu_read(lock_kicker_irq);" macro
blows up with "__bad_size_call_parameter()" as the size of the
returned structure is not within the parameters of what it expects
and optimizes for.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
arch/x86/xen/spinlock.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 3002ec1..d6c1857 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -7,6 +7,7 @@
#include <linux/debugfs.h>
#include <linux/log2.h>
#include <linux/gfp.h>
+#include <linux/slab.h>
#include <asm/paravirt.h>
@@ -165,6 +166,7 @@ static int xen_spin_trylock(struct arch_spinlock *lock)
return old == 0;
}
+static DEFINE_PER_CPU(char *, irq_name);
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
static DEFINE_PER_CPU(struct xen_spinlock *, lock_spinners);
@@ -385,6 +387,7 @@ void __cpuinit xen_init_lock_cpu(int cpu)
if (irq >= 0) {
disable_irq(irq); /* make sure it's never delivered */
per_cpu(lock_kicker_irq, cpu) = irq;
+ per_cpu(irq_name, cpu) = name;
}
printk("cpu %d spinlock event irq %d\n", cpu, irq);
@@ -401,6 +404,8 @@ void xen_uninit_lock_cpu(int cpu)
unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
per_cpu(lock_kicker_irq, cpu) = -1;
+ kfree(per_cpu(irq_name, cpu));
+ per_cpu(irq_name, cpu) = NULL;
}
void __init xen_init_spinlocks(void)
--
1.8.1.4
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