Re: [PATCH] rcutorture: Avoid problematic critical section nesting on RT
flat view
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2021-08-20 06:54:23
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linux-rt-users, lkml, rcu
On 2021-08-19 22:23:37 [-0500], Scott Wood wrote:
On Tue, 2021-08-17 at 16:40 +0200, Sebastian Andrzej Siewior wrote:quoted
[bigeasy: remove 'preempt_disable(); local_bh_disable(); preempt_enable(); local_bh_enable();' from the examples because this works on RT now. ]Does it actually work? If preemption is disabled during local_bh_disable, softirq_ctrl.lock won't be taken. If you then get preempted between the preempt_enable() and the local_bh_enable(), and another task tries to do local_bh_disable(), won't it successfully get softirq_ctrl.lock, add to softirq_ctrl.cnt, and proceed right into the critical section? Or am I missing something?
No, I mixed it up with migrate_disable/enable. I corrected it while redoing it yesterday.
-Scott
Sebastian _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel