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 08:35:52 -0700 |
| commit | e83d31545f97dd5bf24ad77254afc38e676415c2 (patch) | |
| tree | 9f05071213ee0d525aaf6f0bf144a9ecb19d0f18 | |
| parent | 805b1efb2854bf4ce9219abc44ac431ce10bbd3a (diff) | |
| download | lwn-e83d31545f97dd5bf24ad77254afc38e676415c2.tar.gz lwn-e83d31545f97dd5bf24ad77254afc38e676415c2.zip | |
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associated with the channel list is no longer valid.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 220915459c76..d77219aee9a4 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1377,7 +1377,6 @@ 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 */ @@ -2122,6 +2121,8 @@ 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"); |