[lkml]   [2019]   [Jul]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 5.1 121/138] staging: comedi: amplc_pci230: fix null pointer deref on interrupt
From: Ian Abbott <>

commit 7379e6baeddf580d01feca650ec1ad508b6ea8ee upstream.

The interrupt handler `pci230_interrupt()` causes a null pointer
dereference for a PCI260 card. There is no analog output subdevice for
a PCI260. The `dev->write_subdev` subdevice pointer and therefore the
`s_ao` subdevice pointer variable will be `NULL` for a PCI260. The
following call near the end of the interrupt handler results in the null
pointer dereference for a PCI260:

comedi_handle_events(dev, s_ao);

Fix it by only calling the above function if `s_ao` is valid.

Note that the other uses of `s_ao` in the calls
`pci230_handle_ao_nofifo(dev, s_ao);` and `pci230_handle_ao_fifo(dev,
s_ao);` will never be reached for a PCI260, so they are safe.

Fixes: 39064f23284c ("staging: comedi: amplc_pci230: use comedi_handle_events()")
Cc: <> # v3.19+
Signed-off-by: Ian Abbott <>
Signed-off-by: Greg Kroah-Hartman <>

drivers/staging/comedi/drivers/amplc_pci230.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/staging/comedi/drivers/amplc_pci230.c
+++ b/drivers/staging/comedi/drivers/amplc_pci230.c
@@ -2330,7 +2330,8 @@ static irqreturn_t pci230_interrupt(int
devpriv->intr_running = false;
spin_unlock_irqrestore(&devpriv->isr_spinlock, irqflags);

- comedi_handle_events(dev, s_ao);
+ if (s_ao)
+ comedi_handle_events(dev, s_ao);
comedi_handle_events(dev, s_ai);


 \ /
  Last update: 2019-07-12 14:37    [W:0.347 / U:1.264 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site