| Message ID | 20220711123835.811358-2-nuno.sa@analog.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | make iio inkern interface firmware agnostic | expand |
On Mon, Jul 11, 2022 at 2:38 PM Nuno Sá <nuno.sa@analog.com> wrote: > > 'of_node_put()' can potentially release the memory pointed to by > 'iiospec.np' which would leave us with an invalid pointer (and we would > still pass it in 'of_xlate()'). Note that it is not guaranteed for the > of_node lifespan to be attached to the device (to which is attached) > lifespan so that there is (even though very unlikely) the possibility > for the node to freed while the device is still around. Thus, as there be freed > are indeed some of_xlate users which do access the node, a possible race > is indeed possible. possible ... possible. (I would drop the first one) > As such, we can only release the node after we are done with it.
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c index df74765d33dc..9d87057794fc 100644 --- a/drivers/iio/inkern.c +++ b/drivers/iio/inkern.c @@ -165,9 +165,10 @@ static int __of_iio_channel_get(struct iio_channel *channel, idev = bus_find_device(&iio_bus_type, NULL, iiospec.np, iio_dev_node_match); - of_node_put(iiospec.np); - if (idev == NULL) + if (idev == NULL) { + of_node_put(iiospec.np); return -EPROBE_DEFER; + } indio_dev = dev_to_iio_dev(idev); channel->indio_dev = indio_dev; @@ -175,6 +176,7 @@ static int __of_iio_channel_get(struct iio_channel *channel, index = indio_dev->info->of_xlate(indio_dev, &iiospec); else index = __of_iio_simple_xlate(indio_dev, &iiospec); + of_node_put(iiospec.np); if (index < 0) goto err_put; channel->channel = &indio_dev->channels[index];
'of_node_put()' can potentially release the memory pointed to by 'iiospec.np' which would leave us with an invalid pointer (and we would still pass it in 'of_xlate()'). Note that it is not guaranteed for the of_node lifespan to be attached to the device (to which is attached) lifespan so that there is (even though very unlikely) the possibility for the node to freed while the device is still around. Thus, as there are indeed some of_xlate users which do access the node, a possible race is indeed possible. As such, we can only release the node after we are done with it. Fixes: 17d82b47a215d ("iio: Add OF support") Signed-off-by: Nuno Sá <nuno.sa@analog.com> --- drivers/iio/inkern.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)