x86/irq: Call chip->irq_set_affinity in proper context
authorThomas Gleixner <tglx@linutronix.de>
Thu, 14 Jan 2016 07:43:38 +0000 (08:43 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 3 Mar 2016 23:07:30 +0000 (15:07 -0800)
commit7df19ad4a9f2e4845dce66b6049bbc7a796a7895
tree72cd98e4999f619e00db5e0d373225abb49bad7f
parenteeb241d4f8a1d0c343e0a19c99490e66b7eff346
x86/irq: Call chip->irq_set_affinity in proper context

commit e23b257c293ce4bcc8cabb2aa3097b6ed8a8261a upstream.

setup_ioapic_dest() calls irqchip->irq_set_affinity() completely
unprotected. That's wrong in several aspects:

 - it opens a race window where irq_set_affinity() can be interrupted and the
   irq chip left in unconsistent state.

 - it triggers a lockdep splat when we fix the vector race for 4.3+ because
   vector lock is taken with interrupts enabled.

The proper calling convention is irq descriptor lock held and interrupts
disabled.

Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Jeremiah Mahler <jmmahler@gmail.com>
Cc: andy.shevchenko@gmail.com
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Joe Lawrence <joe.lawrence@stratus.com>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1601140919420.3575@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/kernel/apic/io_apic.c