diff options
| author | Ian Abbott <abbotti@mev.co.uk> | 2012-09-19 19:37:39 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-10-07 08:27:24 -0700 |
| commit | 8455d77c2b1a558aacef5c61c2d2b73dc8237c8b (patch) | |
| tree | 838f12d4df51111783d07ba87a1ee5e156e9df6c | |
| parent | 03acba6021da7f7bde0c0886379873791c6e24bf (diff) | |
staging: comedi: fix memory leak for saved channel list
commit c8cad4c89ee3b15935c532210ae6ebb5c0a2734d upstream.
When `do_cmd_ioctl()` allocates memory for the kernel copy of a channel
list, it frees any previously allocated channel list in
`async->cmd.chanlist` and replaces it with the new one. However, if the
device is ever removed (or "detached") the cleanup code in
`cleanup_device()` in "drivers.c" does not free this memory so it is
lost.
A sensible place to free the kernel copy of the channel list is in
`do_become_nonbusy()` as at that point the comedi asynchronous command
associated with the channel list is no longer valid. Free the channel
list in `do_become_nonbusy()` instead of `do_cmd_ioctl()` and clear the
pointer to prevent it being freed more than once.
Note that `cleanup_device()` could be called at an inappropriate time
while the comedi device is open, but that's a separate bug not related
to this this patch.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 10fe503d165..d80b90fa216 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1088,7 +1088,6 @@ static int do_cmd_ioctl(struct comedi_device *dev, goto cleanup; } - kfree(async->cmd.chanlist); async->cmd = user_cmd; async->cmd.data = NULL; /* load channel/gain list */ @@ -1833,6 +1832,8 @@ void do_become_nonbusy(struct comedi_device *dev, struct comedi_subdevice *s) if (async) { comedi_reset_async_buf(async); async->inttrig = NULL; + kfree(async->cmd.chanlist); + async->cmd.chanlist = NULL; } else { printk(KERN_ERR "BUG: (?) do_become_nonbusy called with async=0\n"); |