linux/arch/x86/kernel/apic
Thomas Gleixner 98229aa36c x86/irq: Plug vector cleanup race
We still can end up with a stale vector due to the following:

CPU0                          CPU1                      CPU2
lock_vector()
data->move_in_progress=0
sendIPI()                       
unlock_vector()
                              set_affinity()
                              assign_irq_vector()
                              lock_vector()             handle_IPI
                              move_in_progress = 1      lock_vector()
                              unlock_vector()
                                                        move_in_progress == 1

So we need to serialize the vector assignment against a pending cleanup. The
solution is rather simple now. We not only check for the move_in_progress flag
in assign_irq_vector(), we also check whether there is still a cleanup pending
in the old_domain cpumask. If so, we return -EBUSY to the caller and let him
deal with it. Though we have to be careful in the cpu unplug case. If the
cleanout has not yet completed then the following setaffinity() call would
return -EBUSY. Add code which prevents this.

Full context is here: http://lkml.kernel.org/r/5653B688.4050809@stratus.com

Reported-and-tested-by: Joe Lawrence <joe.lawrence@stratus.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.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: stable@vger.kernel.org #4.3+
Link: http://lkml.kernel.org/r/20151231160107.207265407@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-01-15 13:44:02 +01:00
..
apic_flat_64.c x86/apic: Use default send single IPI wrapper 2015-11-05 13:07:53 +01:00
apic_noop.c x86/apic: Implement single IPI for apic_noop 2015-11-05 13:07:53 +01:00
apic_numachip.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-01-11 15:37:06 -08:00
apic.c x86/apic: Introduce apic_extnmi command line parameter 2015-12-19 11:07:01 +01:00
bigsmp_32.c x86/apic: Wire up single IPI for bigsmp_apic 2015-11-05 13:07:52 +01:00
htirq.c x86: Constify irqdomain ops 2015-05-05 11:14:48 +02:00
hw_nmi.c nmi: x86: convert to generic nmi handler 2015-07-17 12:23:30 +01:00
io_apic.c x86/irq: Call chip->irq_set_affinity in proper context 2016-01-15 13:43:58 +01:00
ipi.c x86/apic: Provide default send single IPI wrapper 2015-11-05 13:07:53 +01:00
Makefile x86, irq: Move HT IRQ related code from io_apic.c into htirq.c 2014-12-16 14:08:17 +01:00
msi.c x86/irq: Export functions to allow MSI domains in modules 2015-12-20 12:40:49 +01:00
probe_32.c x86/apic: Use default send single IPI wrapper 2015-11-05 13:07:53 +01:00
probe_64.c
vector.c x86/irq: Plug vector cleanup race 2016-01-15 13:44:02 +01:00
x2apic_cluster.c x86/apic: Implement single target IPI function for x2apic_cluster 2015-11-05 13:07:52 +01:00
x2apic_phys.c x86/apic: Implement single IPI for x2apic_phys 2015-11-05 13:07:53 +01:00
x2apic_uv_x.c x86/apic: Wire up single IPI for x2apic_uv 2015-11-05 13:07:53 +01:00