This is a note to let you know that I've just added the patch titled
staging: comedi: prevent auto-unconfig of manually configured devices
to the 3.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
staging-comedi-prevent-auto-unconfig-of-manually-configured-devices.patch
and it can be found in the queue-3.7 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c Mon Sep 17 00:00:00 2001
From: Ian Abbott <[email protected]>
Date: Tue, 4 Dec 2012 15:59:55 +0000
Subject: staging: comedi: prevent auto-unconfig of manually configured devices
From: Ian Abbott <[email protected]>
commit 7d3135af399e92cf4c9bbc5f86b6c140aab3b88c upstream.
When a low-level comedi driver auto-configures a device, a `struct
comedi_dev_file_info` is allocated (as well as a `struct
comedi_device`) by `comedi_alloc_board_minor()`. A pointer to the
hardware `struct device` is stored as a cookie in the `struct
comedi_dev_file_info`. When the low-level comedi driver
auto-unconfigures the device, `comedi_auto_unconfig()` uses the cookie
to find the `struct comedi_dev_file_info` so it can detach the comedi
device from the driver, clean it up and free it.
A problem arises if the user manually unconfigures and reconfigures the
comedi device using the `COMEDI_DEVCONFIG` ioctl so that is no longer
associated with the original hardware device. The problem is that the
cookie is not cleared, so that a call to `comedi_auto_unconfig()` from
the low-level driver will still find it, detach it, clean it up and free
it.
Stop this problem occurring by always clearing the `hardware_device`
cookie in the `struct comedi_dev_file_info` whenever the
`COMEDI_DEVCONFIG` ioctl call is successful.
Signed-off-by: Ian Abbott <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
drivers/staging/comedi/comedi_fops.c | 3 +++
1 file changed, 3 insertions(+)
--- a/drivers/staging/comedi/comedi_fops.c
+++ b/drivers/staging/comedi/comedi_fops.c
@@ -1546,6 +1546,9 @@ static long comedi_unlocked_ioctl(struct
if (cmd == COMEDI_DEVCONFIG) {
rc = do_devconfig_ioctl(dev,
(struct comedi_devconfig __user *)arg);
+ if (rc == 0)
+ /* Evade comedi_auto_unconfig(). */
+ dev_file_info->hardware_device = NULL;
goto done;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.7/staging-comedi-kconfig-comedi_ni_at_a2150-should-select-comedi_fc.patch
queue-3.7/staging-comedi-comedi_test-fix-race-when-cancelling-command.patch
queue-3.7/staging-comedi-prevent-auto-unconfig-of-manually-configured-devices.patch
queue-3.7/staging-comedi-fix-minimum-ao-period-for-ni-625x-and-ni-628x.patch
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