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xen/spinlock: Don't leak interrupt name when offlining. 

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@oracle.com>
This commit is contained in:
Konrad Rzeszutek Wilk 2013-06-05 10:44:47 -04:00
parent b85fffec7f
commit 354e7b7619
1 changed files with 6 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/x86/xen/spinlock.c
View File

@ -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);
@ -362,7 +364,7 @@ static irqreturn_t dummy_handler(int irq, void *dev_id)
void __cpuinit xen_init_lock_cpu(int cpu)
{
int irq;
const char *name;
char *name;
WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on IRQ%d!\n",
cpu, per_cpu(lock_kicker_irq, cpu));
@ -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)