x86/ioapic: Prevent NULL pointer dereference in setup_ioapic_dest()

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Commit 4857c91f0d changed the way how irq affinity is setup in
setup_ioapic_dest() from using the core helper function to
unconditionally calling the irq_set_affinity() callback of the
underlying irq chip.

That results in a NULL pointer dereference for the rare case where the
underlying irq chip is lapic_chip which has no irq_set_affinity()
callback. lapic_chip is occasionally used for the timer interrupt (irq
0).

The fix is simple: Check the availability of the callback instead of
calling it unconditionally.

Fixes: 4857c91f0d "x86/ioapic: Force affinity setting in setup_ioapic_dest()"
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org

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This commit is contained in:

Werner Pawlitschko 2015-10-27 09:08:04 +09:00 • committed by Thomas Gleixner

parent 298a96c12b

commit ababae4410

1 changed files with 3 additions and 1 deletions

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arch/x86/kernel/apic/io_apic.c

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