| Message ID | 1663310366-720-1-git-send-email-shengjiu.wang@nxp.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | rpmsg: char: Avoid double destroy of default endpoint | expand |
On Fri, 16 Sept 2022 at 00:57, Shengjiu Wang <shengjiu.wang@nxp.com> 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 > > Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint of the rpmsg device") > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> > --- > drivers/rpmsg/rpmsg_char.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index 0850ae34fb88..562d545ac0d3 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -76,7 +76,8 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) > > mutex_lock(&eptdev->ept_lock); > if (eptdev->ept) { > - rpmsg_destroy_ept(eptdev->ept); > + if (!eptdev->default_ept) > + rpmsg_destroy_ept(eptdev->ept); > eptdev->ept = NULL; Arnaud - please look into this one. Thanks, Mathieu > } > mutex_unlock(&eptdev->ept_lock); > -- > 2.34.1 >
Hello Shengjiu, On 9/16/22 08:39, 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 > > Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint of the rpmsg device") > Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> > --- > drivers/rpmsg/rpmsg_char.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c > index 0850ae34fb88..562d545ac0d3 100644 > --- a/drivers/rpmsg/rpmsg_char.c > +++ b/drivers/rpmsg/rpmsg_char.c > @@ -76,7 +76,8 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) > > mutex_lock(&eptdev->ept_lock); > if (eptdev->ept) { > - rpmsg_destroy_ept(eptdev->ept); > + if (!eptdev->default_ept) > + rpmsg_destroy_ept(eptdev->ept); > eptdev->ept = NULL; > } > mutex_unlock(&eptdev->ept_lock); Good catch! I tried to reproduce it but without success. Do you set a specific config? Concerning the patch: Could you add a comment, to help to understand the condition? something like "The default endpoint is released by the rpmsg core" With that Reviewed-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> Thanks, Arnaud
diff --git a/drivers/rpmsg/rpmsg_char.c b/drivers/rpmsg/rpmsg_char.c index 0850ae34fb88..562d545ac0d3 100644 --- a/drivers/rpmsg/rpmsg_char.c +++ b/drivers/rpmsg/rpmsg_char.c @@ -76,7 +76,8 @@ int rpmsg_chrdev_eptdev_destroy(struct device *dev, void *data) mutex_lock(&eptdev->ept_lock); if (eptdev->ept) { - rpmsg_destroy_ept(eptdev->ept); + if (!eptdev->default_ept) + rpmsg_destroy_ept(eptdev->ept); eptdev->ept = NULL; } mutex_unlock(&eptdev->ept_lock);
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 Fixes: bea9b79c2d10 ("rpmsg: char: Add possibility to use default endpoint of the rpmsg device") Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com> --- drivers/rpmsg/rpmsg_char.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)