* [PATCH 0/2] Fix two kernel warnings in glink driver
@ 2021-10-25 23:24 Sujit Kautkar
2021-10-25 23:24 ` [PATCH 1/2] rpmsg: glink: Fix use-after-free in qcom_glink_rpdev_release() Sujit Kautkar
0 siblings, 1 reply; 2+ messages in thread
From: Sujit Kautkar @ 2021-10-25 23:24 UTC (permalink / raw)
To: Andy Gross, Ohad Ben-Cohen
Cc: Sibi Sankar, Bjorn Andersson, Stephen Boyd, Sujit Kautkar,
linux-arm-msm, linux-kernel, linux-remoteproc
These changes addresses kernel warnings which shows up after enabling
debug kernel. First one fixes use-after-free warning and second fixes
warning by updating cdev APIs
Sujit Kautkar (2):
rpmsg: glink: Fix use-after-free in qcom_glink_rpdev_release()
rpmsg: glink: Update cdev add/del API in
rpmsg_ctrldev_release_device()
drivers/rpmsg/qcom_glink_native.c | 5 ++++-
drivers/rpmsg/rpmsg_char.c | 5 ++---
2 files changed, 6 insertions(+), 4 deletions(-)
--
2.31.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH 1/2] rpmsg: glink: Fix use-after-free in qcom_glink_rpdev_release()
2021-10-25 23:24 [PATCH 0/2] Fix two kernel warnings in glink driver Sujit Kautkar
@ 2021-10-25 23:24 ` Sujit Kautkar
0 siblings, 0 replies; 2+ messages in thread
From: Sujit Kautkar @ 2021-10-25 23:24 UTC (permalink / raw)
To: Andy Gross, Ohad Ben-Cohen
Cc: Sibi Sankar, Bjorn Andersson, Stephen Boyd, Sujit Kautkar,
Sujit Kautkar, linux-arm-msm, linux-kernel, linux-remoteproc
From: Sujit Kautkar <sujitka@google.com>
qcom_glink_rpdev_release() sets channel->rpdev to NULL. However, with
debug enabled kernel, qcom_glink_rpdev_release() gets delayed due to
delayed kobject release and channel gets released by that time and
triggers below kernel warning. To avoid this use-after-free, add a
condition to checks if channel was already released.
| BUG: KASAN: use-after-free in qcom_glink_rpdev_release+0x54/0x70
| Write of size 8 at addr ffffffaba438e8d0 by task kworker/6:1/54
|
| CPU: 6 PID: 54 Comm: kworker/6:1 Not tainted 5.4.109-lockdep #16
| Hardware name: Google Lazor (rev3+) with KB Backlight (DT)
| Workqueue: events kobject_delayed_cleanup
| Call trace:
| dump_backtrace+0x0/0x284
| show_stack+0x20/0x2c
| dump_stack+0xd4/0x170
| print_address_description+0x3c/0x4a8
| __kasan_report+0x144/0x168
| kasan_report+0x10/0x18
| __asan_report_store8_noabort+0x1c/0x24
| qcom_glink_rpdev_release+0x54/0x70
| device_release+0x68/0x14c
| kobject_delayed_cleanup+0x158/0x2cc
| process_one_work+0x7cc/0x10a4
| worker_thread+0x80c/0xcec
| kthread+0x2a8/0x314
| ret_from_fork+0x10/0x18
Signed-off-by: Sujit Kautkar <sujitka@chromium.org>
---
drivers/rpmsg/qcom_glink_native.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index e1444fefdd1c0..cc3556a9385a9 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -270,6 +270,7 @@ static void qcom_glink_channel_release(struct kref *ref)
spin_unlock_irqrestore(&channel->intent_lock, flags);
kfree(channel->name);
+ channel = NULL;
kfree(channel);
}
@@ -1372,8 +1373,10 @@ static void qcom_glink_rpdev_release(struct device *dev)
{
struct rpmsg_device *rpdev = to_rpmsg_device(dev);
struct glink_channel *channel = to_glink_channel(rpdev->ept);
+ if (channel) {
+ channel->rpdev = NULL;
+ }
- channel->rpdev = NULL;
kfree(rpdev);
}
--
2.31.0
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