From: Ian Abbott Date: Wed, 19 Sep 2012 18:37:39 +0000 (+0100) Subject: staging: comedi: fix memory leak for saved channel list X-Git-Tag: v3.2.32~109 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=2a522045b7ede8773e4966b427391184a2b81d0c;p=profile%2Fivi%2Fkernel-adaptation-intel-automotive.git 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list is in `do_become_nonbusy()` as at that point the comedi asynchronous command associated with the channel list is no longer valid.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 Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings --- diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index c08c719..9465bce 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");