linux-kernel - [PATH RESEND v2 00/10] tty: xuartps: Fix lock ups

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Message-ID: <1447963344-16266-1-git-send-email-soren.brinkmann@xilinx.com>
Date:	Thu, 19 Nov 2015 12:02:14 -0800
From:	Soren Brinkmann <soren.brinkmann@...inx.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.com>
CC:	Michal Simek <michal.simek@...inx.com>,
	<linux-serial@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<linux-kernel@...r.kernel.org>,
	"Soren Brinkmann" <soren.brinkmann@...inx.com>
Subject: [PATH RESEND v2 00/10] tty: xuartps: Fix lock ups

Hi,

I guess this series got probably lost during the merge window. Hence, I
resend the patches.

This is v2, hopefully without any build issues. The changes are the same
as before, just the warning reported by kbuild test robot about unused
variables have been fixed. And, I added one more patch with some
cleanup/refactoring.

I recently found my system locking up under some conditions. I dug
through the code a bit and the result is this collections of various
changes. Some of it may not be required and has just been created out of
half-baked theories and re-reading the documentation. The actual failing
scenarios seem to be:
 - RX IRQ conditions are handled while the receiver is disabled, leaving
   the driver in an infinite loop
 - console_put_char seems to be interrupted by uart_shutdown disabling
   the transmitter while/just before printing

I.e. overall I tried to serialize all operations using the port lock to
avoid such interaction.

	Thanks,
	Sören

Sören Brinkmann (10):
  tty: xuartps: Beautify read-modify writes
  tty: xuartps: Use spinlock to serialize HW access
  tty: xuartps: Always enable transmitter in start_tx
  tty: xuartps: Clear interrupt status register in shutdown
  tty: xuartps: Improve startup function
  tty: xuartps: Keep lock for whole ISR
  tty: xuartps: Acquire port lock for shutdown
  tty: xuartps: Move RX path into helper function
  tty: xuartps: Only handle RX IRQs when RX is enabled
  tty: xuartps: Cleanup: Reformat if-else

 drivers/tty/serial/xilinx_uartps.c | 247 ++++++++++++++++++++-----------------
 1 file changed, 136 insertions(+), 111 deletions(-)

-- 
2.6.3.3.g9bb996a

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