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From: gregkh@linuxfoundation•org (Greg Kroah-Hartman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] serial/amba-pl011: Disable interrupts around TX softirq
Date: Fri, 24 Jul 2015 08:15:59 -0700	[thread overview]
Message-ID: <20150724151559.GA12324@kroah.com> (raw)
In-Reply-To: <20150724095605.GI10670@e103592.cambridge.arm.com>

On Fri, Jul 24, 2015 at 10:56:06AM +0100, Dave Martin wrote:
> On Thu, Jul 23, 2015 at 03:05:50PM -0700, Greg Kroah-Hartman wrote:
> > On Thu, Jul 09, 2015 at 11:57:12AM +0100, Dave Martin wrote:
> > > pl011_tx_softirq() currently uses spin_{,un}lock(), which are not
> > > sufficient to inhibit pl011_int() from being triggered by a local
> > > IRQ and trying to re-take the same lock.  This can lead to
> > > deadlocks.
> > > 
> > > This patch uses the _irq() locking variants instead to ensure that
> > > pl011_int() handling for a given port is deferred until any
> > > pl011_tx_softirq() work for that port is complete.
> > > 
> > > Fixes: 734745caeb9f serial/amba-pl011: Activate TX IRQ passively
> > > Signed-off-by: Dave Martin <Dave.Martin@arm•com>
> > > Tested-by: Robin Murphy <robin.murphy@arm•com>
> > > Tested-by: Stefan Wahren <stefan.wahren@i2se•com>
> > > Cc: stable <stable@vger•kernel.org> # 4.1
> > > ---
> > >  drivers/tty/serial/amba-pl011.c |    4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > This doesn't apply at all to 4.2-rc3, so I can't apply it :(
> 
> This is applicable to 4.1 stable only, since the code this patch fixes
> was replaced in 4.2-rc1.
> 
> Apologies, I didn't make that clear in the text.

I can't do anything with a 4.1-only patch, please read
Documentation/stable_kernel_rules.txt for how to get a patch into the
stable kernel releases.

thanks,

greg k-h

  reply	other threads:[~2015-07-24 15:15 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-09 10:57 [PATCH] serial/amba-pl011: Disable interrupts around TX softirq Dave Martin
2015-07-23 22:05 ` Greg Kroah-Hartman
2015-07-24  9:56   ` Dave Martin
2015-07-24 15:15     ` Greg Kroah-Hartman [this message]
2015-07-24 16:46       ` Dave Martin
  -- strict thread matches above, loose matches on Subject: below --
2015-06-18 13:54 Dave Martin
2015-06-20  9:09 ` Stefan Wahren
2015-06-23 11:13   ` Dave P Martin
2015-06-05 14:07 Dave Martin
2015-06-05 18:03 ` Robin Murphy
2015-06-08 10:34   ` Robin Murphy
2015-06-08 11:34     ` Dave P Martin
2015-06-13  0:39 ` Greg Kroah-Hartman
2015-06-15 10:53   ` Dave P Martin
2015-06-15 11:09   ` Andre Przywara
2015-06-15 14:03     ` Dave Martin

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