Messages in this thread | | | Date | Mon, 11 Jul 2022 10:32:35 -0700 | From | Luis Chamberlain <> | Subject | Re: [PATCH v3 -next 1/1] module: kallsyms: Ensure preemption in add_kallsyms() with PREEMPT_RT |
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On Mon, Jul 11, 2022 at 06:17:19PM +0100, Aaron Tomlin wrote: > The commit 08126db5ff73 ("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: 08126db5ff73 ("module: kallsyms: Fix suspicious rcu usage") > Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Thanks! Queued up!
Luis
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