[PATCH] drm/mst: Fix NULL pointer dereference at drm_dp_add_payload_part2
Jani Nikula
jani.nikula at linux.intel.com
Fri May 10 09:24:12 UTC 2024
On Fri, 10 May 2024, "Lin, Wayne" <Wayne.Lin at amd.com> wrote:
> [Public]
>
>> -----Original Message-----
>> From: Limonciello, Mario <Mario.Limonciello at amd.com>
>> Sent: Friday, May 10, 2024 3:18 AM
>> To: Linux regressions mailing list <regressions at lists.linux.dev>; Wentland, Harry
>> <Harry.Wentland at amd.com>; Lin, Wayne <Wayne.Lin at amd.com>
>> Cc: lyude at redhat.com; imre.deak at intel.com; Leon Weiß <leon.weiss at ruhr-uni-
>> bochum.de>; stable at vger.kernel.org; dri-devel at lists.freedesktop.org; amd-
>> gfx at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
>> Subject: Re: [PATCH] drm/mst: Fix NULL pointer dereference at
>> drm_dp_add_payload_part2
>>
>> On 5/9/2024 07:43, Linux regression tracking (Thorsten Leemhuis) wrote:
>> > On 18.04.24 21:43, Harry Wentland wrote:
>> >> On 2024-03-07 01:29, Wayne Lin wrote:
>> >>> [Why]
>> >>> Commit:
>> >>> - commit 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload
>> >>> allocation/removement") accidently overwrite the commit
>> >>> - commit 54d217406afe ("drm: use mgr->dev in drm_dbg_kms in
>> >>> drm_dp_add_payload_part2") which cause regression.
>> >>>
>> >>> [How]
>> >>> Recover the original NULL fix and remove the unnecessary input
>> >>> parameter 'state' for drm_dp_add_payload_part2().
>> >>>
>> >>> Fixes: 5aa1dfcdf0a4 ("drm/mst: Refactor the flow for payload
>> >>> allocation/removement")
>> >>> Reported-by: Leon Weiß <leon.weiss at ruhr-uni-bochum.de>
>> >>> Link:
>> >>> https://lore.kernel.org/r/38c253ea42072cc825dc969ac4e6b9b600371cc8.c
>> >>> amel at ruhr-uni-bochum.de/
>> >>> Cc: lyude at redhat.com
>> >>> Cc: imre.deak at intel.com
>> >>> Cc: stable at vger.kernel.org
>> >>> Cc: regressions at lists.linux.dev
>> >>> Signed-off-by: Wayne Lin <Wayne.Lin at amd.com>
>> >>
>> >> I haven't been deep in MST code in a while but this all looks pretty
>> >> straightforward and good.
>> >>
>> >> Reviewed-by: Harry Wentland <harry.wentland at amd.com>
>> >
>> > Hmmm, that was three weeks ago, but it seems since then nothing
>> > happened to fix the linked regression through this or some other
>> > patch. Is there a reason? The build failure report from the CI maybe?
>>
>> It touches files outside of amd but only has an ack from AMD. I think we
>> /probably/ want an ack from i915 and nouveau to take it through.
>
> Thanks, Mario!
>
> Hi Thorsten,
> Yeah, like what Mario said. Would also like to have ack from i915 and nouveau.
It usually works better if you Cc the folks you want an ack from! ;)
Acked-by: Jani Nikula <jani.nikula at intel.com>
>
>>
>> >
>> > Wayne Lin, do you know what's up?
>> >
>> > Ciao, Thorsten
>> >
>> >>> ---
>> >>> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 2 +-
>> >>> drivers/gpu/drm/display/drm_dp_mst_topology.c | 4 +---
>> >>> drivers/gpu/drm/i915/display/intel_dp_mst.c | 2 +-
>> >>> drivers/gpu/drm/nouveau/dispnv50/disp.c | 2 +-
>> >>> include/drm/display/drm_dp_mst_helper.h | 1 -
>> >>> 5 files changed, 4 insertions(+), 7 deletions(-)
>> >>>
>> >>> diff --git
>> >>> a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> >>> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> >>> index c27063305a13..2c36f3d00ca2 100644
>> >>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> >>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
>> >>> @@ -363,7 +363,7 @@ void dm_helpers_dp_mst_send_payload_allocation(
>> >>> mst_state = to_drm_dp_mst_topology_state(mst_mgr->base.state);
>> >>> new_payload = drm_atomic_get_mst_payload_state(mst_state,
>> >>> aconnector->mst_output_port);
>> >>>
>> >>> - ret = drm_dp_add_payload_part2(mst_mgr, mst_state->base.state,
>> new_payload);
>> >>> + ret = drm_dp_add_payload_part2(mst_mgr, new_payload);
>> >>>
>> >>> if (ret) {
>> >>> amdgpu_dm_set_mst_status(&aconnector->mst_status,
>> >>> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> >>> b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> >>> index 03d528209426..95fd18f24e94 100644
>> >>> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> >>> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
>> >>> @@ -3421,7 +3421,6 @@
>> EXPORT_SYMBOL(drm_dp_remove_payload_part2);
>> >>> /**
>> >>> * drm_dp_add_payload_part2() - Execute payload update part 2
>> >>> * @mgr: Manager to use.
>> >>> - * @state: The global atomic state
>> >>> * @payload: The payload to update
>> >>> *
>> >>> * If @payload was successfully assigned a starting time slot by
>> >>> drm_dp_add_payload_part1(), this @@ -3430,14 +3429,13 @@
>> EXPORT_SYMBOL(drm_dp_remove_payload_part2);
>> >>> * Returns: 0 on success, negative error code on failure.
>> >>> */
>> >>> int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
>> >>> - struct drm_atomic_state *state,
>> >>> struct drm_dp_mst_atomic_payload *payload)
>> >>> {
>> >>> int ret = 0;
>> >>>
>> >>> /* Skip failed payloads */
>> >>> if (payload->payload_allocation_status !=
>> DRM_DP_MST_PAYLOAD_ALLOCATION_DFP) {
>> >>> - drm_dbg_kms(state->dev, "Part 1 of payload creation for %s
>> failed, skipping part 2\n",
>> >>> + drm_dbg_kms(mgr->dev, "Part 1 of payload creation for %s
>> failed,
>> >>> +skipping part 2\n",
>> >>> payload->port->connector->name);
>> >>> return -EIO;
>> >>> }
>> >>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> >>> b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> >>> index 53aec023ce92..2fba66aec038 100644
>> >>> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> >>> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
>> >>> @@ -1160,7 +1160,7 @@ static void intel_mst_enable_dp(struct
>> intel_atomic_state *state,
>> >>> if (first_mst_stream)
>> >>> intel_ddi_wait_for_fec_status(encoder, pipe_config, true);
>> >>>
>> >>> - drm_dp_add_payload_part2(&intel_dp->mst_mgr, &state->base,
>> >>> + drm_dp_add_payload_part2(&intel_dp->mst_mgr,
>> >>>
>> drm_atomic_get_mst_payload_state(mst_state,
>> >>> connector->port));
>> >>>
>> >>> if (DISPLAY_VER(dev_priv) >= 12)
>> >>> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> >>> b/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> >>> index 0c3d88ad0b0e..88728a0b2c25 100644
>> >>> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> >>> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
>> >>> @@ -915,7 +915,7 @@ nv50_msto_cleanup(struct drm_atomic_state *state,
>> >>> msto->disabled = false;
>> >>> drm_dp_remove_payload_part2(mgr, new_mst_state,
>> old_payload, new_payload);
>> >>> } else if (msto->enabled) {
>> >>> - drm_dp_add_payload_part2(mgr, state, new_payload);
>> >>> + drm_dp_add_payload_part2(mgr, new_payload);
>> >>> msto->enabled = false;
>> >>> }
>> >>> }
>> >>> diff --git a/include/drm/display/drm_dp_mst_helper.h
>> >>> b/include/drm/display/drm_dp_mst_helper.h
>> >>> index 9b19d8bd520a..6c9145abc7e2 100644
>> >>> --- a/include/drm/display/drm_dp_mst_helper.h
>> >>> +++ b/include/drm/display/drm_dp_mst_helper.h
>> >>> @@ -851,7 +851,6 @@ int drm_dp_add_payload_part1(struct
>> drm_dp_mst_topology_mgr *mgr,
>> >>> struct drm_dp_mst_topology_state *mst_state,
>> >>> struct drm_dp_mst_atomic_payload *payload);
>> >>> int drm_dp_add_payload_part2(struct drm_dp_mst_topology_mgr *mgr,
>> >>> - struct drm_atomic_state *state,
>> >>> struct drm_dp_mst_atomic_payload *payload);
>> >>> void drm_dp_remove_payload_part1(struct drm_dp_mst_topology_mgr
>> *mgr,
>> >>> struct drm_dp_mst_topology_state *mst_state,
>> >>
>> >>
>> >>
>> >
> ---
> Regards,
> Wayne Lin
--
Jani Nikula, Intel
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