From: Steven Rostedt (Red Hat) <rostedt@goodmis.org>
Date: Wed, 13 Mar 2013 15:15:19 +0000 (-0400)
Subject: tracing: Fix free of probe entry by calling call_rcu_sched()
X-Git-Tag: v3.2.42~34
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1e6cd6bdd31e809cf307be7239f0aacdf9f09544;p=pandora-kernel.git

tracing: Fix free of probe entry by calling call_rcu_sched()

commit 740466bc89ad8bd5afcc8de220f715f62b21e365 upstream.

Because function tracing is very invasive, and can even trace
calls to rcu_read_lock(), RCU access in function tracing is done
with preempt_disable_notrace(). This requires a synchronize_sched()
for updates and not a synchronize_rcu().

Function probes (traceon, traceoff, etc) must be freed after
a synchronize_sched() after its entry has been removed from the
hash. But call_rcu() is used. Fix this by using call_rcu_sched().

Also fix the usage to use hlist_del_rcu() instead of hlist_del().

Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

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