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27 March 2024, 02:37:15 UTC
Revision f6175f5bfb4c9f2ed32758c95f765b529b1a7f15 authored by Tomoki Sekiyama on 28 May 2012, 09:09:18 UTC, committed by Ingo Molnar on 06 June 2012, 10:03:25 UTC 
x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs
 
In current Linux, percpu variable `vector_irq' is not cleared on
offlined cpus while disabling devices' irqs. If the cpu that has
the disabled irqs in vector_irq is hotplugged,
__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

This patch fixes this bug by clearing vector_irq in
__clear_irq_vector() even if the cpu is offlined.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama.qu@hitachi.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: yrl.pp-manager.tt@hitachi.com
Cc: ltc-kernel@ml.yrl.intra.hitachi.co.jp
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/4FC340BE.7080101@hitachi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent 55c844a
History
Tip revision: f6175f5bfb4c9f2ed32758c95f765b529b1a7f15 authored by Tomoki Sekiyama on 28 May 2012, 09:09:18 UTC
x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs
Tip revision: f6175f5
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