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Commit 514f1eb5 authored Feb 15, 2016 by Paul E. McKenney

documentation: Document illegality of call_rcu() from offline CPUs

There is already a blanket statement about no member of RCU's API
being legal from an offline CPU, but add an explicit note where it
states that it is illegal to invoke call_rcu() from an NMI handler.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

parent d8936c0b

Documentation/RCU/Design/Requirements/Requirements.html

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1354,7 +1354,8 @@ situations where neither <tt>synchronize_rcu()</tt> nor
	<tt>synchronize_rcu_expedited()</tt> would be legal,		<tt>synchronize_rcu_expedited()</tt> would be legal,
	including within preempt-disable code, <tt>local_bh_disable()</tt> code,		including within preempt-disable code, <tt>local_bh_disable()</tt> code,
	interrupt-disable code, and interrupt handlers.		interrupt-disable code, and interrupt handlers.
	However, even <tt>call_rcu()</tt> is illegal within NMI handlers.		However, even <tt>call_rcu()</tt> is illegal within NMI handlers
			and from offline CPUs.
	The callback function (<tt>remove_gp_cb()</tt> in this case) will be		The callback function (<tt>remove_gp_cb()</tt> in this case) will be
	executed within softirq (software interrupt) environment within the		executed within softirq (software interrupt) environment within the
	Linux kernel,		Linux kernel,

Documentation/RCU/Design/Requirements/Requirements.htmlx

+2 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1513,7 +1513,8 @@ situations where neither <tt>synchronize_rcu()</tt> nor
	<tt>synchronize_rcu_expedited()</tt> would be legal,		<tt>synchronize_rcu_expedited()</tt> would be legal,
	including within preempt-disable code, <tt>local_bh_disable()</tt> code,		including within preempt-disable code, <tt>local_bh_disable()</tt> code,
	interrupt-disable code, and interrupt handlers.		interrupt-disable code, and interrupt handlers.
	However, even <tt>call_rcu()</tt> is illegal within NMI handlers.		However, even <tt>call_rcu()</tt> is illegal within NMI handlers
			and from offline CPUs.
	The callback function (<tt>remove_gp_cb()</tt> in this case) will be		The callback function (<tt>remove_gp_cb()</tt> in this case) will be
	executed within softirq (software interrupt) environment within the		executed within softirq (software interrupt) environment within the
	Linux kernel,		Linux kernel,