Here is the change log entry from the link I posted above:
Date: Mon Aug 17 14:34:59 2009 -0700
clockevent: Prevent dead lock on clockevents_lock
Currently clockevents_notify() is called with interrupts enabled at
some places and interrupts disabled at some other places.
This results in a deadlock in this scenario.
cpu A holds clockevents_lock in clockevents_notify() with irqs enabled
cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled
cpu C doing set_mtrr() which will try to rendezvous of all the cpus.
This will result in C and A come to the rendezvous point and waiting
for B. B is stuck forever waiting for the spinlock and thus not
reaching the rendezvous point.
Fix the clockevents code so that clockevents_lock is taken with
interrupts disabled and thus avoid the above deadlock.
Also call lapic_timer_propagate_broadcast() on the destination cpu so
that we avoid calling smp_call_function() in the clockevents notifier
chain.
This issue left us wondering if we need to change the MTRR rendezvous
logic to use stop machine logic (instead of smp_call_function) or add
a check in spinlock debug code to see if there are other spinlocks
which gets taken under both interrupts enabled/disabled conditions.
Signed-off-by: Suresh Siddha <suresh.b.sid...@intel.com>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallip...@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallip...@intel.com>
Cc: "Brown Len" <len.br...@intel.com>
LKML-Reference: <1250544899.2709.210.ca...@sbs-t61.sc.intel.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
--
Server 8.04 LTS: soft lockup - CPU#1 stuck for 11s! [bond1:3795] - bond - bond0
https://bugs.launchpad.net/bugs/245779
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