ftrace: Add comment to why rcu_dereference_sched() is open coded

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[ Upstream commit 16052dd5bd ]

Because the function graph tracer can execute in sections where RCU is not
"watching", the rcu_dereference_sched() for the has needs to be open coded.
This is fine because the RCU "flavor" of the ftrace hash is protected by
its own RCU handling (it does its own little synchronization on every CPU
and does not rely on RCU sched).

Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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Steven Rostedt (VMware) 2020-02-05 02:17:57 -05:00 • committed by Greg Kroah-Hartman

parent 0c51e4351b

commit 1cd057a400

1 changed files with 10 additions and 0 deletions

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kernel/trace/trace.h

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