module: kallsyms: Ensure preemption in add_kallsyms() with PREEMPT_RT
The commit 08126db5 ("module: kallsyms: Fix suspicious rcu usage") under PREEMPT_RT=y, disabling preemption introduced an unbounded latency since the loop is not fixed. This change caused a regression since previously preemption was not disabled and we would dereference RCU-protected pointers explicitly. That being said, these pointers cannot change. Before kallsyms-specific data is prepared/or set-up, we ensure that the unformed module is known to be unique i.e. does not already exist (see load_module()). Therefore, we can fix this by using the common and more appropriate RCU flavour as this section of code can be safely preempted. Reported-by:Steven Rostedt <rostedt@goodmis.org> Fixes: 08126db5 ("module: kallsyms: Fix suspicious rcu usage") Signed-off-by:
Aaron Tomlin <atomlin@redhat.com> Signed-off-by:
Luis Chamberlain <mcgrof@kernel.org>
parent
2cc39179
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