From: Matthias Kaehlcke <mka@chromium.org> stable inclusion from stable-v5.10.96 commit fcaf94c49a846ffeaf3efb0faa95a13951ce08c8 bugzilla: https://gitee.com/openeuler/kernel/issues/I55NWB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 7a534ae89e34e9b51acb5a63dd0f88308178b46a upstream. struct rpmsg_eptdev contains a struct cdev. The current code frees the rpmsg_eptdev struct in rpmsg_eptdev_destroy(), but the cdev is a managed object, therefore its release is not predictable and the rpmsg_eptdev could be freed before the cdev is entirely released. The cdev_device_add/del() API was created to address this issue (see commit '233ed09d7fda ("chardev: add helper function to register char devs with a struct device")'), use it instead of cdev add/del(). Fixes: c0cdc19f84a4 ("rpmsg: Driver for user space endpoint interface") Suggested-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Reviewed-by: Stephen Boyd <swboyd@chromium.org> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Link: https://lore.kernel.org/r/20220110104706.v6.2.Idde68b05b88d4a2e6e54766c653f3... Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- drivers/rpmsg/rpmsg_char.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index 8816b1923cdb..be90d77c5168 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -92,7 +92,7 @@ static int rpmsg_eptdev_destroy(struct device *dev, void *data) /* wake up any blocked readers */ wake_up_interruptible(&eptdev->readq); - device_del(&eptdev->dev); + cdev_device_del(&eptdev->cdev, &eptdev->dev); put_device(&eptdev->dev); return 0; @@ -332,7 +332,6 @@ static void rpmsg_eptdev_release_device(struct device *dev) ida_simple_remove(&rpmsg_ept_ida, dev->id); ida_simple_remove(&rpmsg_minor_ida, MINOR(eptdev->dev.devt)); - cdev_del(&eptdev->cdev); kfree(eptdev); } @@ -377,19 +376,13 @@ static int rpmsg_eptdev_create(struct rpmsg_ctrldev *ctrldev, dev->id = ret; dev_set_name(dev, "rpmsg%d", ret); - ret = cdev_add(&eptdev->cdev, dev->devt, 1); + ret = cdev_device_add(&eptdev->cdev, &eptdev->dev); if (ret) goto free_ept_ida; /* We can now rely on the release function for cleanup */ dev->release = rpmsg_eptdev_release_device; - ret = device_add(dev); - if (ret) { - dev_err(dev, "device_add failed: %d\n", ret); - put_device(dev); - } - return ret; free_ept_ida: -- 2.20.1