Hi,
In current Linux, 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.
Commit f6175f5bfb4c partially fixes this, but was not enough in
environments with IOMMU IRQ remapper.
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 __fixup_irqs() when
the cpu is offlined.
Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama...@hitachi.com>
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Ingo Molnar <mi...@redhat.com>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: Suresh Siddha <suresh.b.sid...@intel.com>
Cc: Yinghai Lu <ying...@kernel.org>
Cc: Alexander Gordeev <agord...@redhat.com>
---
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 3dafc60..d27b27d 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
--
1.7.7.6
--
Tomoki Sekiyama <tomoki.sekiyama...@hitachi.com>
Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
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