Quoting Dan Carpenter (2020-04-29 14:24:25)
> If intel_context_create() fails then it leads to an error pointer
> dereference. I shuffled things around to make error handling easier.
>
> Fixes: 1dd47b54baea ("drm/i915: Add live selftests for indirect ctx batchbuffers")
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gt/selftest_lrc.c | 30 +++++++++++++++-----------
> 1 file changed, 18 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/selftest_lrc.c b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> index d3fa91aed7dee..c4bfad5c49dea 100644
> --- a/drivers/gpu/drm/i915/gt/selftest_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/selftest_lrc.c
> @@ -5795,26 +5795,29 @@ static int indirect_ctx_bb_check(struct intel_context *ce)
> static int __live_lrc_indirect_ctx_bb(struct intel_engine_cs *engine)
> {
> struct intel_context *a, *b;
> - int err = 0;
> + int err;
>
> a = intel_context_create(engine);
> - b = intel_context_create(engine);
> -
> + if (IS_ERR(a))
> + return PTR_ERR(a);
> err = intel_context_pin(a);
> if (err)
> - return err;
> + goto put_a;
>
> - err = intel_context_pin(b);
> - if (err) {
> - intel_context_put(a);
> - return err;
> + b = intel_context_create(engine);
> + if (IS_ERR(b)) {
> + err = PTR_ERR(b);
> + goto unpin_a;
> }
> + err = intel_context_pin(b);
> + if (err)
> + goto put_b;
>
> /* We use the already reserved extra page in context state */
> if (!a->wa_bb_page) {
> GEM_BUG_ON(b->wa_bb_page);
> GEM_BUG_ON(INTEL_GEN(engine->i915) == 12);
> - goto out;
> + goto unpin_b;
> }
>
> /*
> @@ -5829,14 +5832,17 @@ static int __live_lrc_indirect_ctx_bb(struct intel_engine_cs *engine)
>
> err = indirect_ctx_bb_check(a);
> if (err)
> - goto out;
> + goto unpin_b;
>
> err = indirect_ctx_bb_check(b);
> -out:
> +
> +unpin_b:
> intel_context_unpin(b);
> +put_b:
> intel_context_put(b);
> -
> +unpin_a:
> intel_context_unpin(a);
> +put_a:
> intel_context_put(a);
Onion looks correct, and there should not be any issue with this
sequence of create/pin.
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
-Chris
