Messages in this thread | | | Date | Fri, 4 May 2018 10:52:41 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] kernel/signal: Remove no longer required irqsave/restore |
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On Fri, May 04, 2018 at 12:17:20PM -0500, Eric W. Biederman wrote: > Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes: > > > On 2018-05-04 11:59:08 [-0500], Eric W. Biederman wrote: > >> Sebastian Andrzej Siewior <bigeasy@linutronix.de> writes: > >> > From: Anna-Maria Gleixner <anna-maria@linutronix.de> > > … > >> > This long-term fix has been made in commit 4abf91047cf ("rtmutex: Make > > >> > wait_lock irq safe") for different reason. > >> > >> Which tree has this change been made in? I am not finding the commit > >> you mention above in Linus's tree. > > > > I'm sorry, it should have been commit b4abf91047cf ("rtmutex: Make > > wait_lock irq safe"). > > Can you fix that in your patch description and can you also up the > description of rcu_read_unlock? > > If we don't need to jump through hoops it looks very reasonable to > remove this unnecessary logic. But we should fix the description > in rcu_read_unlock that still says we need these hoops.
The hoops are still required for rcu_read_lock(), otherwise you get deadlocks between the scheduler and RCU in PREEMPT=y kernels. What happens with this patch (if I understand it correctly) is that the signal code now uses a different way of jumping through the hoops. But the hoops are still jumped through.
Thanx, Paul
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