diff options
| author | Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com> | 2012-07-26 19:47:32 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2012-07-26 15:01:17 +0200 |
| commit | 1d44b30f35a9873a65b320dd5300088fa995fd94 (patch) | |
| tree | 4ca7693f3afed97c3ef7b046b529363d06f44b08 /arch/x86/kernel/irq.c | |
| parent | d431adfbc9b7de651f3164c6b7ffcad75805d7e4 (diff) | |
x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs
In the current kernel, percpu variable `vector_irq' is not always
cleared when a CPU is offlined. If the CPU that has the disabled
irqs in vector_irq is hotplugged again, __setup_vector_irq()
hits invalid irq vector and may crash.
This bug can be reproduced as following;
# echo 0 > /sys/devices/system/cpu/cpu7/online
# modprobe -r some_driver_using_interrupts # vector_irq@cpu7 uncleared
# echo 1 > /sys/devices/system/cpu/cpu7/online # kernel may crash
To fix this problem, this patch clears vector_irq in
__fixup_irqs() when the CPU is offlined.
This also reverts commit f6175f5bfb4c, which partially fixes
this bug by clearing vector in __clear_irq_vector(). But in
environments with IOMMU IRQ remapper, it could fail because
cfg->domain doesn't contain offlined CPUs. With this patch, the
fix in __clear_irq_vector() can be reverted because every
vector_irq is already cleared in __fixup_irqs() on offlined CPUs.
Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120726104732.2889.19144.stgit@kvmdev
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/irq.c')
| -rw-r--r-- | arch/x86/kernel/irq.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 1f5f1d5d2a02..7ad683d78645 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -328,6 +328,7 @@ void fixup_irqs(void) chip->irq_retrigger(data); raw_spin_unlock(&desc->lock); } + __this_cpu_write(vector_irq[vector], -1); } } #endif |