From 6721f28a26efd6368497abbdef5dcfc59608d899 Mon Sep 17 00:00:00 2001 From: Simon Lindgren Date: Tue, 26 Aug 2014 21:13:24 +0200 Subject: [PATCH] i2c: at91: Fix a race condition during signal handling in at91_do_twi_xfer. There is a race condition in at91_do_twi_xfer when signals arrive. If a signal is recieved while waiting for a transfer to complete wait_for_completion_interruptible_timeout() will return -ERESTARTSYS. This is not handled correctly resulting in interrupts still being enabled and a transfer being in flight when we return. Symptoms include a range of oopses and bus lockups. Oopses can happen when the transfer completes because the interrupt handler will corrupt the stack. If a new transfer is started before the interrupt fires the controller will start a new transfer in the middle of the old one, resulting in confused slaves and a locked bus. To avoid this, use wait_for_completion_io_timeout instead so that we don't have to deal with gracefully shutting down the transfer and disabling the interrupts. Signed-off-by: Simon Lindgren Acked-by: Ludovic Desroches Signed-off-by: Wolfram Sang Cc: stable@kernel.org --- Reading git-format-patch failed