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([2600:4040:5c6c:a300::feb]) by smtp.gmail.com with ESMTPSA id a27-20020ac844bb000000b004035843ec96sm1681935qto.89.2023.09.22.12.23.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 22 Sep 2023 12:23:53 -0700 (PDT) Message-ID: Subject: Re: [PATCH v1] drm/dp/mst: fix missing modeset unlock for MST port detect From: Lyude Paul To: imre.deak@intel.com Cc: Ramya SR , David Airlie , Daniel Vetter , Wayne Lin , Jani Nikula , Alex Deucher , Jeff Layton , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Date: Fri, 22 Sep 2023 15:23:52 -0400 In-Reply-To: References: <1694753689-29782-1-git-send-email-quic_rsr@quicinc.com> <19ce2cd9abfd3bdf3ea91f9bceb43206e4740c2e.camel@redhat.com> Organization: Red Hat Inc. Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org =E2=80=A6ugh, 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: > >=20 > > Oh! wow thank you for catching this: > >=20 > > Reviewed-by: Lyude Paul > >=20 > > I will go and push this to drm-misc-next in just a moment > >=20 > > 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. > > >=20 > > > Signed-off-by: Ramya SR > > > --- > > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +++- > > > 1 file changed, 3 insertions(+), 1 deletion(-) > > >=20 > > > 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 *co= nnector, > > > =20 > > > ret =3D drm_modeset_lock(&mgr->base.lock, ctx); > > > if (ret) > > > - goto out; > > > + goto fail; > > > =20 > > > ret =3D connector_status_disconnected; > > > =20 > > > @@ -4181,6 +4181,8 @@ drm_dp_mst_detect_port(struct drm_connector *co= nnector, > > > break; > > > } > > > out: > > > + drm_modeset_unlock(&mgr->base.lock); >=20 > Isn't this supposed to be unlocked only by drm_helper_probe_detect_ctx() > / drm_helper_probe_detect() ? >=20 > > > +fail: > > > drm_dp_mst_topology_put_port(port); > > > return ret; > > > } > >=20 > > --=20 > > Cheers, > > Lyude Paul (she/her) > > Software Engineer at Red Hat > >=20 >=20 --=20 Cheers, Lyude Paul (she/her) Software Engineer at Red Hat