On 2021-08-19 22:23:37 [-0500], Scott Wood wrote: > On Tue, 2021-08-17 at 16:40 +0200, Sebastian Andrzej Siewior wrote: > > [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
