linux-toradex.git/arch/x86/kernel/apic, branch v4.4.7 Linux kernel for Apalis and Colibri modules x86/irq: Cure live lock in fixup_irqs() 2016-04-12T16:08:37+00:00 Thomas Gleixner tglx@linutronix.de 2016-03-14T08:40:46+00:00 dc1441612fdb4ca221e3a4aa32e39e74d020e386 commit 551adc60573cb68e3d55cacca9ba1b7437313df7 upstream. Harry reported, that he's able to trigger a system freeze with cpu hot unplug. The freeze turned out to be a live lock caused by recent changes in irq_force_complete_move(). When fixup_irqs() and from there irq_force_complete_move() is called on the dying cpu, then all other cpus are in stop machine an wait for the dying cpu to complete the teardown. If there is a move of an interrupt pending then irq_force_complete_move() sends the cleanup IPI to the cpus in the old_domain mask and waits for them to clear the mask. That's obviously impossible as those cpus are firmly stuck in stop machine with interrupts disabled. I should have known that, but I completely overlooked it being concentrated on the locking issues around the vectors. And the existance of the call to __irq_complete_move() in the code, which actually sends the cleanup IPI made it reasonable to wait for that cleanup to complete. That call was bogus even before the recent changes as it was just a pointless distraction. We have to look at two cases: 1) The move_in_progress flag of the interrupt is set This means the ioapic has been updated with the new vector, but it has not fired yet. In theory there is a race: set_ioapic(new_vector) <-- Interrupt is raised before update is effective, i.e. it's raised on the old vector. So if the target cpu cannot handle that interrupt before the old vector is cleaned up, we get a spurious interrupt and in the worst case the ioapic irq line becomes stale, but my experiments so far have only resulted in spurious interrupts. But in case of cpu hotplug this should be a non issue because if the affinity update happens right before all cpus rendevouz in stop machine, there is no way that the interrupt can be blocked on the target cpu because all cpus loops first with interrupts enabled in stop machine, so the old vector is not yet cleaned up when the interrupt fires. So the only way to run into this issue is if the delivery of the interrupt on the apic/system bus would be delayed beyond the point where the target cpu disables interrupts in stop machine. I doubt that it can happen, but at least there is a theroretical chance. Virtualization might be able to expose this, but AFAICT the IOAPIC emulation is not as stupid as the real hardware. I've spent quite some time over the weekend to enforce that situation, though I was not able to trigger the delayed case. 2) The move_in_progress flag is not set and the old_domain cpu mask is not empty. That means, that an interrupt was delivered after the change and the cleanup IPI has been sent to the cpus in old_domain, but not all CPUs have responded to it yet. In both cases we can assume that the next interrupt will arrive on the new vector, so we can cleanup the old vectors on the cpus in the old_domain cpu mask. Fixes: 98229aa36caa "x86/irq: Plug vector cleanup race" Reported-by: Harry Junior <harryjr@outlook.fr> Tested-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Joe Lawrence <joe.lawrence@stratus.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Ben Hutchings <ben@decadent.org.uk> Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1603140931430.3657@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 551adc60573cb68e3d55cacca9ba1b7437313df7 upstream.

Harry reported, that he's able to trigger a system freeze with cpu hot
unplug. The freeze turned out to be a live lock caused by recent changes in
irq_force_complete_move().

When fixup_irqs() and from there irq_force_complete_move() is called on the
dying cpu, then all other cpus are in stop machine an wait for the dying cpu
to complete the teardown. If there is a move of an interrupt pending then
irq_force_complete_move() sends the cleanup IPI to the cpus in the old_domain
mask and waits for them to clear the mask. That's obviously impossible as
those cpus are firmly stuck in stop machine with interrupts disabled.

I should have known that, but I completely overlooked it being concentrated on
the locking issues around the vectors. And the existance of the call to
__irq_complete_move() in the code, which actually sends the cleanup IPI made
it reasonable to wait for that cleanup to complete. That call was bogus even
before the recent changes as it was just a pointless distraction.

We have to look at two cases:

1) The move_in_progress flag of the interrupt is set

   This means the ioapic has been updated with the new vector, but it has not
   fired yet. In theory there is a race:

   set_ioapic(new_vector) <-- Interrupt is raised before update is effective,
   			      i.e. it's raised on the old vector.

   So if the target cpu cannot handle that interrupt before the old vector is
   cleaned up, we get a spurious interrupt and in the worst case the ioapic
   irq line becomes stale, but my experiments so far have only resulted in
   spurious interrupts.

   But in case of cpu hotplug this should be a non issue because if the
   affinity update happens right before all cpus rendevouz in stop machine,
   there is no way that the interrupt can be blocked on the target cpu because
   all cpus loops first with interrupts enabled in stop machine, so the old
   vector is not yet cleaned up when the interrupt fires.

   So the only way to run into this issue is if the delivery of the interrupt
   on the apic/system bus would be delayed beyond the point where the target
   cpu disables interrupts in stop machine. I doubt that it can happen, but at
   least there is a theroretical chance. Virtualization might be able to
   expose this, but AFAICT the IOAPIC emulation is not as stupid as the real
   hardware.

   I've spent quite some time over the weekend to enforce that situation,
   though I was not able to trigger the delayed case.

2) The move_in_progress flag is not set and the old_domain cpu mask is not
   empty.

   That means, that an interrupt was delivered after the change and the
   cleanup IPI has been sent to the cpus in old_domain, but not all CPUs have
   responded to it yet.

In both cases we can assume that the next interrupt will arrive on the new
vector, so we can cleanup the old vectors on the cpus in the old_domain cpu
mask.

Fixes: 98229aa36caa "x86/irq: Plug vector cleanup race"
Reported-by: Harry Junior <harryjr@outlook.fr>
Tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Joe Lawrence <joe.lawrence@stratus.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Ben Hutchings <ben@decadent.org.uk>
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1603140931430.3657@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Plug vector cleanup race 2016-03-03T23:07:32+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:54+00:00 996c591227d988ed82e76080ebf4ed0f1f33e0f1 commit 98229aa36caa9c769b13565523de9b813013c703 upstream. 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> Link: http://lkml.kernel.org/r/20151231160107.207265407@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 98229aa36caa9c769b13565523de9b813013c703 upstream.

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>
Link: http://lkml.kernel.org/r/20151231160107.207265407@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Call irq_force_move_complete with irq descriptor 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:53+00:00 4f45a0edf314c4f7f4be658bf58e0b7bc477723c commit 90a2282e23f0522e4b3f797ad447c5e91bf7fe32 upstream. First of all there is no point in looking up the irq descriptor again, but we also need the descriptor for the final cleanup race fix in the next patch. Make that change seperate. No functional difference. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160107.125211743@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 90a2282e23f0522e4b3f797ad447c5e91bf7fe32 upstream.

First of all there is no point in looking up the irq descriptor again, but we
also need the descriptor for the final cleanup race fix in the next
patch. Make that change seperate. No functional difference.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160107.125211743@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Remove outgoing CPU from vector cleanup mask 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:52+00:00 950c362bdfb191aa3b149493c0447c89845f3a87 commit 56d7d2f4bbd00fb198b7907cb3ab657d06115a42 upstream. We want to synchronize new vector assignments with a pending cleanup. Remove a dying cpu from a pending cleanup mask. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160107.045961667@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 56d7d2f4bbd00fb198b7907cb3ab657d06115a42 upstream.

We want to synchronize new vector assignments with a pending cleanup. Remove a
dying cpu from a pending cleanup mask.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160107.045961667@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Remove the cpumask allocation from send_cleanup_vector() 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:52+00:00 00bb447126d363fbf401d973548b193828c83fb2 commit 5da0c1217f05d2ccc9a8ed6e6e5c23a8a1d24dd6 upstream. There is no need to allocate a new cpumask for sending the cleanup vector. The old_domain mask is now protected by the vector_lock, so we can safely remove the offline cpus from it and send the IPI with the resulting mask. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160106.967993932@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5da0c1217f05d2ccc9a8ed6e6e5c23a8a1d24dd6 upstream.

There is no need to allocate a new cpumask for sending the cleanup vector. The
old_domain mask is now protected by the vector_lock, so we can safely remove
the offline cpus from it and send the IPI with the resulting mask.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160106.967993932@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Clear move_in_progress before sending cleanup IPI 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:51+00:00 c2b56b62c26ec51f64edea8d20b133efeddd2d0c commit c1684f5035b60e9f98566493e869496fb5de1d89 upstream. send_cleanup_vector() fiddles with the old_domain mask unprotected because it relies on the protection by the move_in_progress flag. But this is fatal, as the flag is reset after the IPI has been sent. So a cpu which receives the IPI can still see the flag set and therefor ignores the cleanup request. If no other cleanup request happens then the vector stays stale on that cpu and in case of an irq removal the vector still persists. That can lead to use after free when the next cleanup IPI happens. Protect the code with vector_lock and clear move_in_progress before sending the IPI. This does not plug the race which Joe reported because: 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 The full fix comes with a later patch. 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> Link: http://lkml.kernel.org/r/20151231160106.892412198@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit c1684f5035b60e9f98566493e869496fb5de1d89 upstream.

send_cleanup_vector() fiddles with the old_domain mask unprotected because it
relies on the protection by the move_in_progress flag. But this is fatal, as
the flag is reset after the IPI has been sent. So a cpu which receives the IPI
can still see the flag set and therefor ignores the cleanup request. If no
other cleanup request happens then the vector stays stale on that cpu and in
case of an irq removal the vector still persists. That can lead to use after
free when the next cleanup IPI happens.

Protect the code with vector_lock and clear move_in_progress before sending
the IPI.

This does not plug the race which Joe reported because:

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

The full fix comes with a later patch.

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>
Link: http://lkml.kernel.org/r/20151231160106.892412198@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Remove offline cpus from vector cleanup 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:50+00:00 550ac3f791f5cdf26021dfa6011adcb5f38856b6 commit 847667ef10356b824a11c853fc8a8b1b437b6a8d upstream. No point of keeping offline cpus in the cleanup mask. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160106.808642683@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 847667ef10356b824a11c853fc8a8b1b437b6a8d upstream.

No point of keeping offline cpus in the cleanup mask.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160106.808642683@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Get rid of code duplication 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:49+00:00 c655fd016c2917c5f88c4c694bdcdf9e68f4f661 commit ab25ac02148b600e645f77cfb8b8ea415ed75bb4 upstream. Reusing an existing vector and assigning a new vector has duplicated code. Consolidate it. This is also a preparatory patch for finally plugging the cleanup race. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160106.721599216@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit ab25ac02148b600e645f77cfb8b8ea415ed75bb4 upstream.

Reusing an existing vector and assigning a new vector has duplicated
code. Consolidate it.

This is also a preparatory patch for finally plugging the cleanup race.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160106.721599216@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Copy vectormask instead of an AND operation 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:49+00:00 2636de2fc22c1f5e1b24ba7d9e6f6615ed9569a5 commit 9ac15b7a8af4cf3337a101498c0ed690d23ade75 upstream. In the case that the new vector mask is a subset of the existing mask there is no point to do a AND operation of currentmask & newmask. The result is newmask. So we can simply copy the new mask to the current mask and be done with it. Preparatory patch for further consolidation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160106.640253454@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9ac15b7a8af4cf3337a101498c0ed690d23ade75 upstream.

In the case that the new vector mask is a subset of the existing mask there is
no point to do a AND operation of currentmask & newmask. The result is
newmask. So we can simply copy the new mask to the current mask and be done
with it. Preparatory patch for further consolidation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160106.640253454@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/irq: Check vector allocation early 2016-03-03T23:07:31+00:00 Thomas Gleixner tglx@linutronix.de 2015-12-31T16:30:48+00:00 4af6a215154b213835420c6cd2442c0436abbad5 commit 3716fd27a604d61a91cda47083504971486b80f1 upstream. __assign_irq_vector() uses the vector_cpumask which is assigned by apic->vector_allocation_domain() without doing basic sanity checks. That can result in a situation where the final assignement of a newly found vector fails in apic->cpu_mask_to_apicid_and(). So we have to do rollbacks for no reason. apic->cpu_mask_to_apicid_and() only fails if vector_cpumask & requested_cpumask & cpu_online_mask is empty. Check for this condition right away and if the result is empty try immediately the next possible cpu in the requested mask. So in case of a failure the old setting is unchanged and we can remove the rollback code. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov <bp@alien8.de> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> 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> Link: http://lkml.kernel.org/r/20151231160106.561877324@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3716fd27a604d61a91cda47083504971486b80f1 upstream.

__assign_irq_vector() uses the vector_cpumask which is assigned by
apic->vector_allocation_domain() without doing basic sanity checks. That can
result in a situation where the final assignement of a newly found vector
fails in apic->cpu_mask_to_apicid_and(). So we have to do rollbacks for no
reason.

apic->cpu_mask_to_apicid_and() only fails if

  vector_cpumask & requested_cpumask & cpu_online_mask

is empty.

Check for this condition right away and if the result is empty try immediately
the next possible cpu in the requested mask. So in case of a failure the old
setting is unchanged and we can remove the rollback code.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Borislav Petkov <bp@alien8.de>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
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>
Link: http://lkml.kernel.org/r/20151231160106.561877324@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>