* [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint
@ 2022-09-21 1:58 Shengjiu Wang
2022-09-21 8:18 ` Peng Fan
2022-09-21 17:34 ` Mathieu Poirier
0 siblings, 2 replies; 3+ messages in thread
From: Shengjiu Wang @ 2022-09-21 1:58 UTC (permalink / raw)
To: andersson, mathieu.poirier, arnaud.pouliquen
Cc: linux-remoteproc, linux-kernel, shengjiu.wang
The rpmsg_dev_remove() in rpmsg_core is the place for releasing
this default endpoint.
So need to avoid destroying the default endpoint in
rpmsg_chrdev_eptdev_destroy(), this should be the same as
rpmsg_eptdev_release(). Otherwise there will be double destroy
issue that ept->refcount report warning:
refcount_t: underflow; use-after-free.
Call trace:
refcount_warn_saturate+0xf8/0x150
virtio_rpmsg_destroy_ept+0xd4/0xec
rpmsg_dev_remove+0x60/0x70
The issue can be reproduced by stopping remoteproc before
closing the /dev/rpmsgX.
Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint of the rpmsg device")
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
---
changes in v2:
- Add comments
drivers/rpmsg/rpmsg_char.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
index 0850ae34fb88..3e0b8f3496ed 100644
--- a/drivers/rpmsg/rpmsg_char.c
+++ b/drivers/rpmsg/rpmsg_char.c
@@ -76,7 +76,9 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
mutex_lock(&eptdev->ept_lock);
if (eptdev->ept) {
- rpmsg_destroy_ept(eptdev->ept);
+ /* The default endpoint is released by the rpmsg core */
+ if (!eptdev->default_ept)
+ rpmsg_destroy_ept(eptdev->ept);
eptdev->ept = NULL;
}
mutex_unlock(&eptdev->ept_lock);
--
2.34.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* RE: [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint
2022-09-21 1:58 [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint Shengjiu Wang
@ 2022-09-21 8:18 ` Peng Fan
2022-09-21 17:34 ` Mathieu Poirier
1 sibling, 0 replies; 3+ messages in thread
From: Peng Fan @ 2022-09-21 8:18 UTC (permalink / raw)
To: S.J. Wang, andersson@kernel.org, mathieu.poirier@linaro.org,
arnaud.pouliquen@foss.st.com
Cc: linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
shengjiu.wang@gmail.com
> Subject: [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint
>
> The rpmsg_dev_remove() in rpmsg_core is the place for releasing this
> default endpoint.
>
> So need to avoid destroying the default endpoint in
> rpmsg_chrdev_eptdev_destroy(), this should be the same as
> rpmsg_eptdev_release(). Otherwise there will be double destroy issue that
> ept->refcount report warning:
>
> refcount_t: underflow; use-after-free.
>
> Call trace:
> refcount_warn_saturate+0xf8/0x150
> virtio_rpmsg_destroy_ept+0xd4/0xec
> rpmsg_dev_remove+0x60/0x70
>
> The issue can be reproduced by stopping remoteproc before closing the
> /dev/rpmsgX.
>
> Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint
> of the rpmsg device")
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> changes in v2:
> - Add comments
>
> drivers/rpmsg/rpmsg_char.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 0850ae34fb88..3e0b8f3496ed 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -76,7 +76,9 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev,
> void *data)
>
> mutex_lock(&eptdev->ept_lock);
> if (eptdev->ept) {
> - rpmsg_destroy_ept(eptdev->ept);
> + /* The default endpoint is released by the rpmsg core */
> + if (!eptdev->default_ept)
> + rpmsg_destroy_ept(eptdev->ept);
> eptdev->ept = NULL;
> }
> mutex_unlock(&eptdev->ept_lock);
> --
Reviewed-by: Peng Fan <peng.fan@nxp.com>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint
2022-09-21 1:58 [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint Shengjiu Wang
2022-09-21 8:18 ` Peng Fan
@ 2022-09-21 17:34 ` Mathieu Poirier
1 sibling, 0 replies; 3+ messages in thread
From: Mathieu Poirier @ 2022-09-21 17:34 UTC (permalink / raw)
To: Shengjiu Wang
Cc: andersson, arnaud.pouliquen, linux-remoteproc, linux-kernel,
shengjiu.wang
On Wed, Sep 21, 2022 at 09:58:43AM +0800, Shengjiu Wang wrote:
> The rpmsg_dev_remove() in rpmsg_core is the place for releasing
> this default endpoint.
>
> So need to avoid destroying the default endpoint in
> rpmsg_chrdev_eptdev_destroy(), this should be the same as
> rpmsg_eptdev_release(). Otherwise there will be double destroy
> issue that ept->refcount report warning:
>
> refcount_t: underflow; use-after-free.
>
> Call trace:
> refcount_warn_saturate+0xf8/0x150
> virtio_rpmsg_destroy_ept+0xd4/0xec
> rpmsg_dev_remove+0x60/0x70
>
> The issue can be reproduced by stopping remoteproc before
> closing the /dev/rpmsgX.
>
> Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint of the rpmsg device")
> Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
> Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
> changes in v2:
> - Add comments
>
> drivers/rpmsg/rpmsg_char.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c
> index 0850ae34fb88..3e0b8f3496ed 100644
> --- a/drivers/rpmsg/rpmsg_char.c
> +++ b/drivers/rpmsg/rpmsg_char.c
> @@ -76,7 +76,9 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data)
>
> mutex_lock(&eptdev->ept_lock);
> if (eptdev->ept) {
> - rpmsg_destroy_ept(eptdev->ept);
> + /* The default endpoint is released by the rpmsg core */
> + if (!eptdev->default_ept)
> + rpmsg_destroy_ept(eptdev->ept);
Applied.
Thanks,
Mathieu
> eptdev->ept = NULL;
> }
> mutex_unlock(&eptdev->ept_lock);
> --
> 2.34.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-09-21 1:58 [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint Shengjiu Wang
2022-09-21 8:18 ` Peng Fan
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