On 09/01/2023 01:28, Dmitry Baryshkov wrote:
On 22/12/2022 01:19, Marijn Suijten wrote: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) 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 <marijn.suijten@xxxxxxxxxxxxxx> --- drivers/gpu/drm/msm/disp/dpu1/dpu_rm.c | 5 +++++ 1 file changed, 5 insertions(+)I think the patch is not fully correct. Please check resource availability during allocation. I wouldn't expect an error from get_assigned_resources because of resource exhaustion.
Another option, since allocation functions (except DSC) already have these safety checks: check error message to mention internal inconstency: allocated resource doesn't exist.
-- With best wishes Dmitry
