Messages in this thread | | | Date | Mon, 28 Sep 2020 10:06:13 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 2/2] sched: mark PRINTK_DEFERRED_CONTEXT_MASK in __schedule() |
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On Mon, Sep 28, 2020 at 10:00:22AM +0200, Peter Zijlstra wrote: > On Mon, Sep 28, 2020 at 12:52:44AM -0700, Joe Perches wrote: > > On Mon, 2020-09-28 at 09:32 +0200, Peter Zijlstra wrote: > > > On Mon, Sep 28, 2020 at 12:11:30AM +0800, Chengming Zhou wrote: > > > > The WARN_ON/WARN_ON_ONCE with rq lock held in __schedule() should be > > > > deferred by marking the PRINTK_DEFERRED_CONTEXT_MASK, or will cause > > > > deadlock on rq lock in the printk path. > > [] > > > NAK printk_deferred is an abomination, kill that. > > > > Didn't you introduce it? > > Should you be complaining to yourself? > > Yeah. I should've hacked around it then I suppose. Still, no reason to > proliferate that crap. Afaik the new printk should be able to deal with > this at some point. > > The thing we're not going to do it add a cache-miss to schedule just > because.
Also, using deferred for WARN/BUG is fundamentally wrong, you want that splat _NOW_, there might not be a later.
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