Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 19/58] staging: comedi: fix memory leak for saved channel list | Date | Thu, 4 Oct 2012 14:19:26 -0700 |
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3.5-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott <abbotti@mev.co.uk>
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list is in `do_become_nonbusy()` as at that point the comedi asynchronous command associated with the channel list is no longer valid.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>
--- drivers/staging/comedi/comedi_fops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- 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_de 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_dev 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");
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