From 9e1e236acdc42b5c43ec8d7f03a39537e70cc309 Mon Sep 17 00:00:00 2001 From: Marijn Suijten Date: Tue, 10 Jan 2023 00:15:55 +0100 Subject: drm/msm/dpu: Disallow unallocated resources to be returned [ Upstream commit abc40122d9a69f56c04efb5a7485795f5ac799d1 ] In the event that the topology requests resources that have not been created by the system (because they are typically not represented in dpu_mdss_cfg ^1), the resource(s) in global_state (in this case DSC blocks, until their allocation/assignment is being sanity-checked in "drm/msm/dpu: Reject topologies for which no DSC blocks are available") remain NULL but will still be returned out of dpu_rm_get_assigned_resources, where the caller expects to get an array containing num_blks valid pointers (but instead gets these NULLs). To prevent this from happening, where null-pointer dereferences typically result in a hard-to-debug platform lockup, num_blks shouldn't increase past NULL blocks and will print an error and break instead. After all, max_blks represents the static size of the maximum number of blocks whereas the actual amount varies per platform. ^1: which can happen after a git rebase ended up moving additions to _dpu_cfg to a different struct which has the same patch context. Fixes: bb00a452d6f7 ("drm/msm/dpu: Refactor resource manager") Signed-off-by: Marijn Suijten Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/517636/ Link: https://lore.kernel.org/r/20230109231556.344977-1-marijn.suijten@somainline.org Signed-off-by: Dmitry Baryshkov Signed-off-by: Sasha Levin --- drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'drivers/gpu/drm/msm/disp') diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c index 73b3442e7467..7ada957adbbb 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c @@ -660,6 +660,11 @@ int dpu_rm_get_assigned_resources(struct dpu_rm *rm, blks_size, enc_id); break; } + if (!hw_blks[i]) { + DPU_ERROR("Allocated resource %d unavailable to assign to enc %d\n", + type, enc_id); + break; + } blks[num_blks++] = hw_blks[i]; } -- cgit v1.2.3