diff options
| author | Simon Lindgren <simon@aqwary.com> | 2014-08-26 21:13:24 +0200 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2014-09-02 14:29:20 +0200 |
| commit | 6721f28a26efd6368497abbdef5dcfc59608d899 (patch) | |
| tree | ab605a2947c61973e2c3b30a14deb74ce7141239 /drivers/i2c/busses | |
| parent | 0ce4bc1dbdd911ae1763e2d4ff36bd1b214a59f7 (diff) | |
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 <simon@aqwary.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
Diffstat (limited to 'drivers/i2c/busses')
| -rw-r--r-- | drivers/i2c/busses/i2c-at91.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c index 79a68999a696..ec299ae17a5a 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -421,8 +421,8 @@ static int at91_do_twi_transfer(struct at91_twi_dev *dev) } } - ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, - dev->adapter.timeout); + ret = wait_for_completion_io_timeout(&dev->cmd_complete, + dev->adapter.timeout); if (ret == 0) { dev_err(dev->dev, "controller timed out\n"); at91_init_twi_bus(dev); |