Messages in this thread Patch in this message | | | Date | Tue, 04 Jun 2013 19:22:40 +0200 | From | Willy Tarreau <> | Subject | [ 070/184] staging: comedi: fix memory leak for saved channel |
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2.6.32-longterm review patch. If anyone has any objections, please let me know.
------------------ list
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list is in `do_become_nonbusy()` as at that point the comedi asynchronous command associated with the channel list is no longer valid.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> Signed-off-by: Willy Tarreau <w@1wt.eu> --- drivers/staging/comedi/comedi_fops.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 908f25a..b83c76f 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -1035,7 +1035,6 @@ static int do_cmd_ioctl(struct comedi_device *dev, void *arg, void *file) goto cleanup; } - kfree(async->cmd.chanlist); async->cmd = user_cmd; async->cmd.data = NULL; /* load channel/gain list */ @@ -1759,6 +1758,8 @@ 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"); -- 1.7.12.2.21.g234cd45.dirty
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