cros_ec_sensors_push_data() reads `indio_dev->active_scan_mask` and
calls iio_push_to_buffers_with_timestamp() without making sure the
`indio_dev` stays in buffer mode. There is a race if `indio_dev` exits
buffer mode right before cros_ec_sensors_push_data() accesses them.
An use-after-free on `indio_dev->active_scan_mask` was observed. The
call trace:
[...]
_find_next_bit
cros_ec_sensors_push_data
cros_ec_sensorhub_event
blocking_notifier_call_chain
cros_ec_irq_thread
It was …
[View More]caused by a race condition: one thread just freed
`active_scan_mask` at [1]; while another thread tried to access the
memory at [2].
Fix it by calling iio_device_claim_buffer_mode() to ensure the
`indio_dev` can't exit buffer mode during cros_ec_sensors_push_data().
[1]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/industrialio-buffe…
[2]: https://elixir.bootlin.com/linux/v6.5/source/drivers/iio/common/cros_ec_sen…
Cc: stable(a)vger.kernel.org
Fixes: aa984f1ba4a4 ("iio: cros_ec: Register to cros_ec_sensorhub when EC supports FIFO")
Signed-off-by: Tzung-Bi Shih <tzungbi(a)kernel.org>
---
Changes from v1(https://patchwork.kernel.org/project/linux-iio/patch/20230828094339.1248…:
- Use iio_device_{claim|release}_buffer_mode() instead of accessing `mlock`.
drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
index b72d39fc2434..6bfe5d6847e7 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -190,8 +190,11 @@ int cros_ec_sensors_push_data(struct iio_dev *indio_dev,
/*
* Ignore samples if the buffer is not set: it is needed if the ODR is
* set but the buffer is not enabled yet.
+ *
+ * Note: iio_device_claim_buffer_mode() returns -EBUSY if the buffer
+ * is not enabled.
*/
- if (!iio_buffer_enabled(indio_dev))
+ if (iio_device_claim_buffer_mode(indio_dev) < 0)
return 0;
out = (s16 *)st->samples;
@@ -210,6 +213,7 @@ int cros_ec_sensors_push_data(struct iio_dev *indio_dev,
iio_push_to_buffers_with_timestamp(indio_dev, st->samples,
timestamp + delta);
+ iio_device_release_buffer_mode(indio_dev);
return 0;
}
EXPORT_SYMBOL_GPL(cros_ec_sensors_push_data);
--
2.42.0.rc2.253.gd59a3bf2b4-goog
[View Less]
The rtnl lock also needs to be held before rndis_filter_device_add()
which advertises nvsp_2_vsc_capability / sriov bit, and triggers
VF NIC offering and registering. If VF NIC finished register_netdev()
earlier it may cause name based config failure.
To fix this issue, move the call to rtnl_lock() before
rndis_filter_device_add(), so VF will be registered later than netvsc
/ synthetic NIC, and gets a name numbered (ethX) after netvsc.
Cc: stable(a)vger.kernel.org
Fixes: e04e7a7bbd4b ("…
[View More]hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
Reported-by: Dexuan Cui <decui(a)microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz(a)microsoft.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek(a)intel.com>
---
v3:
Divide it into two patches, suggested by Jakub Kicinski.
v2:
Fix rtnl_unlock() in error handling as found by Wojciech Drewek.
---
drivers/net/hyperv/netvsc_drv.c | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 3ba3c8fb28a5..5e528a76f5f5 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2531,15 +2531,6 @@ static int netvsc_probe(struct hv_device *dev,
goto devinfo_failed;
}
- nvdev = rndis_filter_device_add(dev, device_info);
- if (IS_ERR(nvdev)) {
- ret = PTR_ERR(nvdev);
- netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
- goto rndis_failed;
- }
-
- eth_hw_addr_set(net, device_info->mac_adr);
-
/* We must get rtnl lock before scheduling nvdev->subchan_work,
* otherwise netvsc_subchan_work() can get rtnl lock first and wait
* all subchannels to show up, but that may not happen because
@@ -2547,9 +2538,23 @@ static int netvsc_probe(struct hv_device *dev,
* -> ... -> device_add() -> ... -> __device_attach() can't get
* the device lock, so all the subchannels can't be processed --
* finally netvsc_subchan_work() hangs forever.
+ *
+ * The rtnl lock also needs to be held before rndis_filter_device_add()
+ * which advertises nvsp_2_vsc_capability / sriov bit, and triggers
+ * VF NIC offering and registering. If VF NIC finished register_netdev()
+ * earlier it may cause name based config failure.
*/
rtnl_lock();
+ nvdev = rndis_filter_device_add(dev, device_info);
+ if (IS_ERR(nvdev)) {
+ ret = PTR_ERR(nvdev);
+ netdev_err(net, "unable to add netvsc device (ret %d)\n", ret);
+ goto rndis_failed;
+ }
+
+ eth_hw_addr_set(net, device_info->mac_adr);
+
if (nvdev->num_chn > 1)
schedule_work(&nvdev->subchan_work);
@@ -2586,9 +2591,9 @@ static int netvsc_probe(struct hv_device *dev,
return 0;
register_failed:
- rtnl_unlock();
rndis_filter_device_remove(dev, nvdev);
rndis_failed:
+ rtnl_unlock();
netvsc_devinfo_put(device_info);
devinfo_failed:
free_percpu(net_device_ctx->vf_stats);
--
2.25.1
[View Less]
commit f79936545fb122856bd78b189d3c7ee59928c751 upstream.
This patch fixes a boot failure that happens with VMs running with
SEV-ES or SEV-SNP when the guest kernel is compiled with a gcc version
past 12.3 (or possibly earlier) due to undefined behavior. As far as I
know, the UB has existed ever since SEV-ES guest support was merged in
(I believe 5.9), but only started causing boot failures with the
updated compiler. Thus, I propose backporting this patch to stable
branches since 5.9.