Messages in this thread | | | Date | Thu, 12 Jul 2018 12:30:01 -0600 | From | Tycho Andersen <> | Subject | Re: [PATCH v4] uart: fix race between uart_put_char() and uart_shutdown() |
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On Thu, Jul 12, 2018 at 08:25:45PM +0200, Greg Kroah-Hartman wrote: > On Thu, Jul 12, 2018 at 12:18:46PM -0600, Tycho Andersen wrote: > > On Thu, Jul 12, 2018 at 05:40:15PM +0200, Greg Kroah-Hartman wrote: > > > On Thu, Jul 12, 2018 at 09:08:22AM -0600, Tycho Andersen wrote: > > > > On Thu, Jul 12, 2018 at 05:04:38PM +0200, Greg Kroah-Hartman wrote: > > > > > On Wed, Jul 11, 2018 at 10:07:44AM -0600, Tycho Andersen wrote: > > > > > > + if (uport) > > > > > > + spin_lock_irqsave(&uport->lock, flags); > > > > > > > > > > That's the same thing as just calling uart_port_lock(), why aren't you > > > > > doing that? > > > > > > > > Because the compiler can't seem to "see" through the macros/ref calls, > > > > and I get the warning I mentioned here if I use them: > > > > > > > > https://lkml.org/lkml/2018/7/6/840 > > > > > > What horrible version of gcc are you using that give you that? Don't > > > open-code things just because of a broken compiler. > > > > I've tried with both 7.3.0 and 5.4.0. I think the reason we see this > > here but not elsewhere in the file is because there's an actual > > function call (free_page()) in the critical section. > > > > If we move that out, something like the below patch, it all works for > > me. > > Ick. Which version of this series had the problem? Let me test it out > here...
v3, if you remove the initialization of flags from both functions you should see it.
Tycho
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