c0729eeefd
Éric Piel reported a kernel oops in the "comedi_test" module. It was a NULL pointer dereference within `waveform_ai_interrupt()` (actually a timer function) that sometimes occurred when a running asynchronous command is cancelled (either by the `COMEDI_CANCEL` ioctl or by closing the device file). This seems to be a race between the caller of `waveform_ai_cancel()` which on return from that function goes and tears down the running command, and the timer function which uses the command. In particular, `async->cmd.chanlist` gets freed (and the pointer set to NULL) by `do_become_nonbusy()` in "comedi_fops.c" but a previously scheduled `waveform_ai_interrupt()` timer function will dereference that pointer regardless, leading to the oops. Fix it by replacing the `del_timer()` call in `waveform_ai_cancel()` with `del_timer_sync()`. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Reported-by: Éric Piel <piel@delmic.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
||
|---|---|---|
| .. | ||
| drivers | ||
| kcomedilib | ||
| Kconfig | ||
| Makefile | ||
| TODO | ||
| comedi.h | ||
| comedi_compat32.c | ||
| comedi_compat32.h | ||
| comedi_fops.c | ||
| comedi_internal.h | ||
| comedidev.h | ||
| comedilib.h | ||
| drivers.c | ||
| proc.c | ||
| range.c | ||