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    SubjectRe: [PATCH v2] rpmsg: char: Avoid double destroy of default endpoint
    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
    >

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