* [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
@ 2023-09-15 4:54 Ramya SR
2023-09-22 9:41 ` Ramya SR
2023-09-22 19:02 ` Lyude Paul
0 siblings, 2 replies; 11+ messages in thread
From: Ramya SR @ 2023-09-15 4:54 UTC (permalink / raw)
To: David Airlie, Daniel Vetter, Lyude Paul, Wayne Lin, Jani Nikula,
Imre Deak, Alex Deucher, Jeff Layton, dri-devel, linux-kernel
Cc: Ramya SR
Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
This will lead to deadlock if calling the function multiple times in
an atomic operation, for example, getting imultiple MST ports status
for a DP MST bonding scenario.
Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ed96cfc..d6512c4 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
ret = drm_modeset_lock(&mgr->base.lock, ctx);
if (ret)
- goto out;
+ goto fail;
ret = connector_status_disconnected;
@@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
break;
}
out:
+ drm_modeset_unlock(&mgr->base.lock);
+fail:
drm_dp_mst_topology_put_port(port);
return ret;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-15 4:54 [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect Ramya SR
@ 2023-09-22 9:41 ` Ramya SR
2023-09-22 19:02 ` Lyude Paul
1 sibling, 0 replies; 11+ messages in thread
From: Ramya SR @ 2023-09-22 9:41 UTC (permalink / raw)
To: Ramya SR (QUIC),
David Airlie, Daniel Vetter, Lyude Paul, Wayne Lin, Jani Nikula,
Imre Deak, Alex Deucher, Jeff Layton, dri-devel, linux-kernel
Gentle Reminder. Please review the commit.
-----Original Message-----
From: Ramya SR (QUIC) <quic_rsr@quicinc.com>
Sent: Friday, September 15, 2023 10:25 AM
To: David Airlie <airlied@gmail.com>; Daniel Vetter <daniel@ffwll.ch>; Lyude Paul <lyude@redhat.com>; Wayne Lin <Wayne.Lin@amd.com>; Jani Nikula <jani.nikula@intel.com>; Imre Deak <imre.deak@intel.com>; Alex Deucher <alexander.deucher@amd.com>; Jeff Layton <jlayton@kernel.org>; dri-devel@lists.freedesktop.org; linux-kernel@vger.kernel.org
Cc: Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
This will lead to deadlock if calling the function multiple times in an atomic operation, for example, getting imultiple MST ports status for a DP MST bonding scenario.
Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index ed96cfc..d6512c4 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
ret = drm_modeset_lock(&mgr->base.lock, ctx);
if (ret)
- goto out;
+ goto fail;
ret = connector_status_disconnected;
@@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
break;
}
out:
+ drm_modeset_unlock(&mgr->base.lock);
+fail:
drm_dp_mst_topology_put_port(port);
return ret;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-15 4:54 [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect Ramya SR
2023-09-22 9:41 ` Ramya SR
@ 2023-09-22 19:02 ` Lyude Paul
2023-09-22 19:22 ` Imre Deak
1 sibling, 1 reply; 11+ messages in thread
From: Lyude Paul @ 2023-09-22 19:02 UTC (permalink / raw)
To: Ramya SR, David Airlie, Daniel Vetter, Wayne Lin, Jani Nikula,
Imre Deak, Alex Deucher, Jeff Layton, dri-devel, linux-kernel
Oh! wow thank you for catching this:
Reviewed-by: Lyude Paul <lyude@redhat.com>
I will go and push this to drm-misc-next in just a moment
On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> This will lead to deadlock if calling the function multiple times in
> an atomic operation, for example, getting imultiple MST ports status
> for a DP MST bonding scenario.
>
> Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> ---
> drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index ed96cfc..d6512c4 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
>
> ret = drm_modeset_lock(&mgr->base.lock, ctx);
> if (ret)
> - goto out;
> + goto fail;
>
> ret = connector_status_disconnected;
>
> @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> break;
> }
> out:
> + drm_modeset_unlock(&mgr->base.lock);
> +fail:
> drm_dp_mst_topology_put_port(port);
> return ret;
> }
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-22 19:02 ` Lyude Paul
@ 2023-09-22 19:22 ` Imre Deak
2023-09-22 19:23 ` Lyude Paul
2023-09-25 14:57 ` Alex Deucher
0 siblings, 2 replies; 11+ messages in thread
From: Imre Deak @ 2023-09-22 19:22 UTC (permalink / raw)
To: Lyude Paul
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR
On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
>
> Oh! wow thank you for catching this:
>
> Reviewed-by: Lyude Paul <lyude@redhat.com>
>
> I will go and push this to drm-misc-next in just a moment
>
> On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > This will lead to deadlock if calling the function multiple times in
> > an atomic operation, for example, getting imultiple MST ports status
> > for a DP MST bonding scenario.
> >
> > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > ---
> > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > index ed96cfc..d6512c4 100644
> > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> >
> > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > if (ret)
> > - goto out;
> > + goto fail;
> >
> > ret = connector_status_disconnected;
> >
> > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > break;
> > }
> > out:
> > + drm_modeset_unlock(&mgr->base.lock);
Isn't this supposed to be unlocked only by drm_helper_probe_detect_ctx()
/ drm_helper_probe_detect() ?
> > +fail:
> > drm_dp_mst_topology_put_port(port);
> > return ret;
> > }
>
> --
> Cheers,
> Lyude Paul (she/her)
> Software Engineer at Red Hat
>
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-22 19:22 ` Imre Deak
@ 2023-09-22 19:23 ` Lyude Paul
2023-09-25 14:57 ` Alex Deucher
1 sibling, 0 replies; 11+ messages in thread
From: Lyude Paul @ 2023-09-22 19:23 UTC (permalink / raw)
To: imre.deak
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR
…ugh, thanks for catching that :|
yes you're completely right - NAK on this patch then
On Fri, 2023-09-22 at 22:22 +0300, Imre Deak wrote:
> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
> >
> > Oh! wow thank you for catching this:
> >
> > Reviewed-by: Lyude Paul <lyude@redhat.com>
> >
> > I will go and push this to drm-misc-next in just a moment
> >
> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > > This will lead to deadlock if calling the function multiple times in
> > > an atomic operation, for example, getting imultiple MST ports status
> > > for a DP MST bonding scenario.
> > >
> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > > ---
> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > index ed96cfc..d6512c4 100644
> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > >
> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > > if (ret)
> > > - goto out;
> > > + goto fail;
> > >
> > > ret = connector_status_disconnected;
> > >
> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > > break;
> > > }
> > > out:
> > > + drm_modeset_unlock(&mgr->base.lock);
>
> Isn't this supposed to be unlocked only by drm_helper_probe_detect_ctx()
> / drm_helper_probe_detect() ?
>
> > > +fail:
> > > drm_dp_mst_topology_put_port(port);
> > > return ret;
> > > }
> >
> > --
> > Cheers,
> > Lyude Paul (she/her)
> > Software Engineer at Red Hat
> >
>
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-22 19:22 ` Imre Deak
2023-09-22 19:23 ` Lyude Paul
@ 2023-09-25 14:57 ` Alex Deucher
2023-09-26 10:41 ` Ramya SR
1 sibling, 1 reply; 11+ messages in thread
From: Alex Deucher @ 2023-09-25 14:57 UTC (permalink / raw)
To: imre.deak
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR
On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>
> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
> >
> > Oh! wow thank you for catching this:
> >
> > Reviewed-by: Lyude Paul <lyude@redhat.com>
> >
> > I will go and push this to drm-misc-next in just a moment
> >
> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > > This will lead to deadlock if calling the function multiple times in
> > > an atomic operation, for example, getting imultiple MST ports status
> > > for a DP MST bonding scenario.
> > >
> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > > ---
> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > index ed96cfc..d6512c4 100644
> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > >
> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > > if (ret)
> > > - goto out;
> > > + goto fail;
> > >
> > > ret = connector_status_disconnected;
> > >
> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > > break;
> > > }
> > > out:
> > > + drm_modeset_unlock(&mgr->base.lock);
>
> Isn't this supposed to be unlocked only by drm_helper_probe_detect_ctx()
> / drm_helper_probe_detect() ?
Maybe adding a comment to that effect would be helpful for the future.
Alex
>
> > > +fail:
> > > drm_dp_mst_topology_put_port(port);
> > > return ret;
> > > }
> >
> > --
> > Cheers,
> > Lyude Paul (she/her)
> > Software Engineer at Red Hat
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-25 14:57 ` Alex Deucher
@ 2023-09-26 10:41 ` Ramya SR
2023-09-28 2:25 ` Ramya SR
0 siblings, 1 reply; 11+ messages in thread
From: Ramya SR @ 2023-09-26 10:41 UTC (permalink / raw)
To: Alex Deucher, imre.deak
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR (QUIC)
-----Original Message-----
From: Alex Deucher <alexdeucher@gmail.com>
Sent: Monday, September 25, 2023 8:27 PM
To: imre.deak@intel.com
Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>
> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
> >
> > Oh! wow thank you for catching this:
> >
> > Reviewed-by: Lyude Paul <lyude@redhat.com>
> >
> > I will go and push this to drm-misc-next in just a moment
> >
> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > > This will lead to deadlock if calling the function multiple times
> > > in an atomic operation, for example, getting imultiple MST ports
> > > status for a DP MST bonding scenario.
> > >
> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > > ---
> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > index ed96cfc..d6512c4 100644
> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector
> > > *connector,
> > >
> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > > if (ret)
> > > - goto out;
> > > + goto fail;
> > >
> > > ret = connector_status_disconnected;
> > >
> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > > break;
> > > }
> > > out:
> > > + drm_modeset_unlock(&mgr->base.lock);
>
> Isn't this supposed to be unlocked only by
> drm_helper_probe_detect_ctx() / drm_helper_probe_detect() ?
Maybe adding a comment to that effect would be helpful for the future.
Alex
>this is different lock, above function mentioned is locking/unlocking the global connection_mutex, that is required always locked during the atomic >check/commit. Here we are talking about MST topology manager mutex "mgr->base.lock".
>For normal non-bond MST, it's ok, the calling sequence for detecting MST connector status is
> dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is locked)
> Then for the bond MST case, to figure out if the sibling connectors are also connected, so that the bonding is possible, we need detect two or more connectors >in single dp_mst_connector_detect call
>dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is locked)
>dp_mst_find_sibling_connector ->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port ->drm_dp_mst_detect_port (blocked by mgr->base.lock)
>
> > > +fail:
> > > drm_dp_mst_topology_put_port(port);
> > > return ret;
> > > }
> >
> > --
> > Cheers,
> > Lyude Paul (she/her)
> > Software Engineer at Red Hat
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-26 10:41 ` Ramya SR
@ 2023-09-28 2:25 ` Ramya SR
2023-09-28 8:23 ` Jani Nikula
2023-09-29 4:44 ` Ramya SR
0 siblings, 2 replies; 11+ messages in thread
From: Ramya SR @ 2023-09-28 2:25 UTC (permalink / raw)
To: Alex Deucher, imre.deak
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR (QUIC)
Reminder. Please review the reply comment.
Thanks and Regards,
Ramya SR
-----Original Message-----
From: Ramya SR
Sent: Tuesday, September 26, 2023 4:12 PM
To: Alex Deucher <alexdeucher@gmail.com>; imre.deak@intel.com
Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
-----Original Message-----
From: Alex Deucher <alexdeucher@gmail.com>
Sent: Monday, September 25, 2023 8:27 PM
To: imre.deak@intel.com
Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>
> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
> >
> > Oh! wow thank you for catching this:
> >
> > Reviewed-by: Lyude Paul <lyude@redhat.com>
> >
> > I will go and push this to drm-misc-next in just a moment
> >
> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > > This will lead to deadlock if calling the function multiple times
> > > in an atomic operation, for example, getting imultiple MST ports
> > > status for a DP MST bonding scenario.
> > >
> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > > ---
> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > index ed96cfc..d6512c4 100644
> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector
> > > *connector,
> > >
> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > > if (ret)
> > > - goto out;
> > > + goto fail;
> > >
> > > ret = connector_status_disconnected;
> > >
> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > > break;
> > > }
> > > out:
> > > + drm_modeset_unlock(&mgr->base.lock);
>
> Isn't this supposed to be unlocked only by
> drm_helper_probe_detect_ctx() / drm_helper_probe_detect() ?
Maybe adding a comment to that effect would be helpful for the future.
Alex
>this is different lock, above function mentioned is locking/unlocking the global connection_mutex, that is required always locked during the atomic >check/commit. Here we are talking about MST topology manager mutex "mgr->base.lock".
>For normal non-bond MST, it's ok, the calling sequence for detecting
>MST connector status is dp_mst_connector_detect
>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>->drm_dp_mst_detect_port (where mgr->base.lock is locked)
> Then for the bond MST case, to figure out if the sibling connectors
> are also connected, so that the bonding is possible, we need detect
> two or more connectors >in single dp_mst_connector_detect call
>dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx =
>dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is
>locked) dp_mst_find_sibling_connector
>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>->drm_dp_mst_detect_port (blocked by mgr->base.lock)
>
> > > +fail:
> > > drm_dp_mst_topology_put_port(port);
> > > return ret;
> > > }
> >
> > --
> > Cheers,
> > Lyude Paul (she/her)
> > Software Engineer at Red Hat
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-28 2:25 ` Ramya SR
@ 2023-09-28 8:23 ` Jani Nikula
2023-09-29 4:44 ` Ramya SR
1 sibling, 0 replies; 11+ messages in thread
From: Jani Nikula @ 2023-09-28 8:23 UTC (permalink / raw)
To: Ramya SR, Alex Deucher, imre.deak
Cc: Jeff Layton, linux-kernel, dri-devel, Wayne Lin, Alex Deucher,
Ramya SR (QUIC)
On Thu, 28 Sep 2023, Ramya SR <rsr@qti.qualcomm.com> wrote:
> Reminder. Please review the reply comment.
Maybe send a patch to review?
It's also not helping that your previous mail looks like it's just
quoting other messages [1].
BR,
Jani.
[1] https://lore.kernel.org/all/BN0PR02MB79517B267D593DC484BA34DF81C3A@BN0PR02MB7951.namprd02.prod.outlook.com/
>
> Thanks and Regards,
> Ramya SR
>
> -----Original Message-----
> From: Ramya SR
> Sent: Tuesday, September 26, 2023 4:12 PM
> To: Alex Deucher <alexdeucher@gmail.com>; imre.deak@intel.com
> Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
> Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
>
>
>
> -----Original Message-----
> From: Alex Deucher <alexdeucher@gmail.com>
> Sent: Monday, September 25, 2023 8:27 PM
> To: imre.deak@intel.com
> Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
> Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
>
> WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
>
> On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>>
>> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
>> >
>> > Oh! wow thank you for catching this:
>> >
>> > Reviewed-by: Lyude Paul <lyude@redhat.com>
>> >
>> > I will go and push this to drm-misc-next in just a moment
>> >
>> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
>> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
>> > > This will lead to deadlock if calling the function multiple times
>> > > in an atomic operation, for example, getting imultiple MST ports
>> > > status for a DP MST bonding scenario.
>> > >
>> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
>> > > ---
>> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
>> > > 1 file changed, 3 insertions(+), 1 deletion(-)
>> > >
>> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > index ed96cfc..d6512c4 100644
>> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector
>> > > *connector,
>> > >
>> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
>> > > if (ret)
>> > > - goto out;
>> > > + goto fail;
>> > >
>> > > ret = connector_status_disconnected;
>> > >
>> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
>> > > break;
>> > > }
>> > > out:
>> > > + drm_modeset_unlock(&mgr->base.lock);
>>
>> Isn't this supposed to be unlocked only by
>> drm_helper_probe_detect_ctx() / drm_helper_probe_detect() ?
>
> Maybe adding a comment to that effect would be helpful for the future.
>
> Alex
>
>>this is different lock, above function mentioned is locking/unlocking the global connection_mutex, that is required always locked during the atomic >check/commit. Here we are talking about MST topology manager mutex "mgr->base.lock".
>
>>For normal non-bond MST, it's ok, the calling sequence for detecting
>>MST connector status is dp_mst_connector_detect
>>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>>->drm_dp_mst_detect_port (where mgr->base.lock is locked)
>
>> Then for the bond MST case, to figure out if the sibling connectors
>> are also connected, so that the bonding is possible, we need detect
>> two or more connectors >in single dp_mst_connector_detect call
>
>>dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx =
>>dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is
>>locked) dp_mst_find_sibling_connector
>>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>>->drm_dp_mst_detect_port (blocked by mgr->base.lock)
>
>>
>> > > +fail:
>> > > drm_dp_mst_topology_put_port(port);
>> > > return ret;
>> > > }
>> >
>> > --
>> > Cheers,
>> > Lyude Paul (she/her)
>> > Software Engineer at Red Hat
>> >
--
Jani Nikula, Intel
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-28 2:25 ` Ramya SR
2023-09-28 8:23 ` Jani Nikula
@ 2023-09-29 4:44 ` Ramya SR
2023-09-29 7:53 ` Jani Nikula
1 sibling, 1 reply; 11+ messages in thread
From: Ramya SR @ 2023-09-29 4:44 UTC (permalink / raw)
To: Alex Deucher, imre.deak
Cc: Jani Nikula, Jeff Layton, linux-kernel, dri-devel, Wayne Lin,
Alex Deucher, Ramya SR (QUIC)
Hi All ,
Please review the reply comment.
Regards,
Ramya SR
-----Original Message-----
From: Ramya SR
Sent: Thursday, September 28, 2023 7:55 AM
To: 'Alex Deucher' <alexdeucher@gmail.com>; 'imre.deak@intel.com' <imre.deak@intel.com>
Cc: 'Lyude Paul' <lyude@redhat.com>; 'Jani Nikula' <jani.nikula@intel.com>; 'Jeff Layton' <jlayton@kernel.org>; 'linux-kernel@vger.kernel.org' <linux-kernel@vger.kernel.org>; 'dri-devel@lists.freedesktop.org' <dri-devel@lists.freedesktop.org>; 'Wayne Lin' <Wayne.Lin@amd.com>; 'Alex Deucher' <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
Reminder. Please review the reply comment.
Thanks and Regards,
Ramya SR
-----Original Message-----
From: Ramya SR
Sent: Tuesday, September 26, 2023 4:12 PM
To: Alex Deucher <alexdeucher@gmail.com>; imre.deak@intel.com
Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
-----Original Message-----
From: Alex Deucher <alexdeucher@gmail.com>
Sent: Monday, September 25, 2023 8:27 PM
To: imre.deak@intel.com
Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>
> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
> >
> > Oh! wow thank you for catching this:
> >
> > Reviewed-by: Lyude Paul <lyude@redhat.com>
> >
> > I will go and push this to drm-misc-next in just a moment
> >
> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
> > > This will lead to deadlock if calling the function multiple times
> > > in an atomic operation, for example, getting imultiple MST ports
> > > status for a DP MST bonding scenario.
> > >
> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
> > > ---
> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
> > > 1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > index ed96cfc..d6512c4 100644
> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector
> > > *connector,
> > >
> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
> > > if (ret)
> > > - goto out;
> > > + goto fail;
> > >
> > > ret = connector_status_disconnected;
> > >
> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
> > > break;
> > > }
> > > out:
> > > + drm_modeset_unlock(&mgr->base.lock);
>
> Isn't this supposed to be unlocked only by
> drm_helper_probe_detect_ctx() / drm_helper_probe_detect() ?
Maybe adding a comment to that effect would be helpful for the future.
Alex
>this is different lock, above function mentioned is locking/unlocking the global connection_mutex, that is required always locked during the atomic >check/commit. Here we are talking about MST topology manager mutex "mgr->base.lock".
>For normal non-bond MST, it's ok, the calling sequence for detecting
>MST connector status is dp_mst_connector_detect
>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>->drm_dp_mst_detect_port (where mgr->base.lock is locked)
> Then for the bond MST case, to figure out if the sibling connectors
> are also connected, so that the bonding is possible, we need detect
> two or more connectors >in single dp_mst_connector_detect call
>dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx =
>dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is
>locked) dp_mst_find_sibling_connector
>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>->drm_dp_mst_detect_port (blocked by mgr->base.lock)
>
> > > +fail:
> > > drm_dp_mst_topology_put_port(port);
> > > return ret;
> > > }
> >
> > --
> > Cheers,
> > Lyude Paul (she/her)
> > Software Engineer at Red Hat
> >
^ permalink raw reply [flat|nested] 11+ messages in thread
* RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
2023-09-29 4:44 ` Ramya SR
@ 2023-09-29 7:53 ` Jani Nikula
0 siblings, 0 replies; 11+ messages in thread
From: Jani Nikula @ 2023-09-29 7:53 UTC (permalink / raw)
To: Ramya SR, Alex Deucher, imre.deak
Cc: Jeff Layton, linux-kernel, dri-devel, Wayne Lin, Alex Deucher,
Ramya SR (QUIC)
On Fri, 29 Sep 2023, Ramya SR <rsr@qti.qualcomm.com> wrote:
> Hi All ,
>
> Please review the reply comment.
Please read the responses you do get [1]. Please stop
top-posting. Please fix your mail client.
BR,
Jani.
[1] https://lore.kernel.org/r/877coak8o3.fsf@intel.com
>
> Regards,
> Ramya SR
>
> -----Original Message-----
> From: Ramya SR
> Sent: Thursday, September 28, 2023 7:55 AM
> To: 'Alex Deucher' <alexdeucher@gmail.com>; 'imre.deak@intel.com' <imre.deak@intel.com>
> Cc: 'Lyude Paul' <lyude@redhat.com>; 'Jani Nikula' <jani.nikula@intel.com>; 'Jeff Layton' <jlayton@kernel.org>; 'linux-kernel@vger.kernel.org' <linux-kernel@vger.kernel.org>; 'dri-devel@lists.freedesktop.org' <dri-devel@lists.freedesktop.org>; 'Wayne Lin' <Wayne.Lin@amd.com>; 'Alex Deucher' <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
> Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
>
> Reminder. Please review the reply comment.
>
> Thanks and Regards,
> Ramya SR
>
> -----Original Message-----
> From: Ramya SR
> Sent: Tuesday, September 26, 2023 4:12 PM
> To: Alex Deucher <alexdeucher@gmail.com>; imre.deak@intel.com
> Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
> Subject: RE: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
>
>
>
> -----Original Message-----
> From: Alex Deucher <alexdeucher@gmail.com>
> Sent: Monday, September 25, 2023 8:27 PM
> To: imre.deak@intel.com
> Cc: Lyude Paul <lyude@redhat.com>; Jani Nikula <jani.nikula@intel.com>; Jeff Layton <jlayton@kernel.org>; linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org; Wayne Lin <Wayne.Lin@amd.com>; Alex Deucher <alexander.deucher@amd.com>; Ramya SR (QUIC) <quic_rsr@quicinc.com>
> Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect
>
> WARNING: This email originated from outside of Qualcomm. Please be wary of any links or attachments, and do not enable macros.
>
> On Fri, Sep 22, 2023 at 3:22 PM Imre Deak <imre.deak@intel.com> wrote:
>>
>> On Fri, Sep 22, 2023 at 03:02:23PM -0400, Lyude Paul wrote:
>> >
>> > Oh! wow thank you for catching this:
>> >
>> > Reviewed-by: Lyude Paul <lyude@redhat.com>
>> >
>> > I will go and push this to drm-misc-next in just a moment
>> >
>> > On Fri, 2023-09-15 at 10:24 +0530, Ramya SR wrote:
>> > > Modeset mutex unlock is missing in drm_dp_mst_detect_port function.
>> > > This will lead to deadlock if calling the function multiple times
>> > > in an atomic operation, for example, getting imultiple MST ports
>> > > status for a DP MST bonding scenario.
>> > >
>> > > Signed-off-by: Ramya SR <quic_rsr@quicinc.com>
>> > > ---
>> > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++-
>> > > 1 file changed, 3 insertions(+), 1 deletion(-)
>> > >
>> > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > index ed96cfc..d6512c4 100644
>> > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> > > @@ -4154,7 +4154,7 @@ drm_dp_mst_detect_port(struct drm_connector
>> > > *connector,
>> > >
>> > > ret = drm_modeset_lock(&mgr->base.lock, ctx);
>> > > if (ret)
>> > > - goto out;
>> > > + goto fail;
>> > >
>> > > ret = connector_status_disconnected;
>> > >
>> > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *connector,
>> > > break;
>> > > }
>> > > out:
>> > > + drm_modeset_unlock(&mgr->base.lock);
>>
>> Isn't this supposed to be unlocked only by
>> drm_helper_probe_detect_ctx() / drm_helper_probe_detect() ?
>
> Maybe adding a comment to that effect would be helpful for the future.
>
> Alex
>
>>this is different lock, above function mentioned is locking/unlocking the global connection_mutex, that is required always locked during the atomic >check/commit. Here we are talking about MST topology manager mutex "mgr->base.lock".
>
>>For normal non-bond MST, it's ok, the calling sequence for detecting
>>MST connector status is dp_mst_connector_detect
>>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>>->drm_dp_mst_detect_port (where mgr->base.lock is locked)
>
>> Then for the bond MST case, to figure out if the sibling connectors
>> are also connected, so that the bonding is possible, we need detect
>> two or more connectors >in single dp_mst_connector_detect call
>
>>dp_mst_connector_detect ->mst->mst_fw_cbs->detect_port_ctx =
>>dp_mst_detect_port ->drm_dp_mst_detect_port (where mgr->base.lock is
>>locked) dp_mst_find_sibling_connector
>>->mst->mst_fw_cbs->detect_port_ctx = dp_mst_detect_port
>>->drm_dp_mst_detect_port (blocked by mgr->base.lock)
>
>>
>> > > +fail:
>> > > drm_dp_mst_topology_put_port(port);
>> > > return ret;
>> > > }
>> >
>> > --
>> > Cheers,
>> > Lyude Paul (she/her)
>> > Software Engineer at Red Hat
>> >
--
Jani Nikula, Intel
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2023-09-29 8:23 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-09-15 4:54 [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect Ramya SR
2023-09-22 9:41 ` Ramya SR
2023-09-22 19:02 ` Lyude Paul
2023-09-22 19:22 ` Imre Deak
2023-09-22 19:23 ` Lyude Paul
2023-09-25 14:57 ` Alex Deucher
2023-09-26 10:41 ` Ramya SR
2023-09-28 2:25 ` Ramya SR
2023-09-28 8:23 ` Jani Nikula
2023-09-29 4:44 ` Ramya SR
2023-09-29 7:53 ` Jani Nikula
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