diff options
| author | Simon Lindgren <simon@aqwary.com> | 2014-08-26 23:13:24 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-10-06 00:40:53 +0400 |
| commit | 705ee1e247ee4f99f0a2975d53f14aa037468b8c (patch) | |
| tree | ced80a8c04b0974b2cddd6232078bbe073248b8f /drivers/i2c | |
| parent | b998a12e678d205ca6c8ba37e2bd7f576877b5bc (diff) | |
| download | linux-705ee1e247ee4f99f0a2975d53f14aa037468b8c.tar.xz | |
i2c: at91: Fix a race condition during signal handling in at91_do_twi_xfer.
commit 6721f28a26efd6368497abbdef5dcfc59608d899 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/i2c')
| -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 f963b463769e..e96edab2e30b 100644 --- a/drivers/i2c/busses/i2c-at91.c +++ b/drivers/i2c/busses/i2c-at91.c @@ -434,8 +434,8 @@ 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); |