7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Marek Czernohous [ Upstream commit 843bc34db94bff0612c8294861b156489958897b ] nouveau_dp_irq() looks the encoder up and dereferences it in the same breath, five lines before testing it: struct nouveau_encoder *outp = find_encoder(connector, DCB_OUTPUT_DP); struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev); ... if (!outp) return; find_encoder() walks the connector's possible encoders and returns NULL when none of them matches the requested type, so the NULL test is not decoration: it is the author saying this can happen. The initialiser above it dereferences the same pointer regardless. The NULL test predates the dereference. commit 773eb04d14a1 ("drm/nouveau/disp: expose conn event class") turned nouveau_dp_irq() into a work callback, and since the drm pointer was no longer passed in as an argument it was recovered from the encoder in the declaration block, which put the dereference above the existing test. Move the drm lookup below the test. No functional change when outp is non-NULL. Fixes: 773eb04d14a1 ("drm/nouveau/disp: expose conn event class") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-5 Signed-off-by: Marek Czernohous Reviewed-by: Lyude Paul Signed-off-by: Lyude Paul Link: https://patch.msgid.link/178682366004.3748010.14933649768375463967@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/nouveau/nouveau_dp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c b/drivers/gpu/drm/nouveau/nouveau_dp.c index 55691ec44abaa..738802358d85c 100644 --- a/drivers/gpu/drm/nouveau/nouveau_dp.c +++ b/drivers/gpu/drm/nouveau/nouveau_dp.c @@ -486,7 +486,7 @@ nouveau_dp_irq(struct work_struct *work) container_of(work, typeof(*nv_connector), irq_work); struct drm_connector *connector = &nv_connector->base; struct nouveau_encoder *outp = find_encoder(connector, DCB_OUTPUT_DP); - struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev); + struct nouveau_drm *drm; struct nv50_mstm *mstm; u64 hpd = 0; int ret; @@ -494,6 +494,8 @@ nouveau_dp_irq(struct work_struct *work) if (!outp) return; + drm = nouveau_drm(outp->base.base.dev); + mstm = outp->dp.mstm; NV_DEBUG(drm, "service %s\n", connector->name); -- 2.53.0