| Message ID | 20180319193053.GA7016@embeddedgus (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Quoting Gustavo A. R. Silva (2018-03-19 19:30:53) > _workload_ is being dereferenced before it is null checked, hence > there is a potential null pointer dereference. > > Fix this by moving the pointer dereference after _workload_ has > been null checked. The checks are misleading and not required. -Chris
Hi Chris, On 03/19/2018 03:38 PM, Chris Wilson wrote: > Quoting Gustavo A. R. Silva (2018-03-19 19:30:53) >> _workload_ is being dereferenced before it is null checked, hence >> there is a potential null pointer dereference. >> >> Fix this by moving the pointer dereference after _workload_ has >> been null checked. > > The checks are misleading and not required. All of them? if (!workload || !reg_state || workload->ring_id != RCS) return; or just the null check on workload ? Thanks for the feedback. -- Gustavo
Quoting Gustavo A. R. Silva (2018-03-19 20:50:12) > Hi Chris, > > On 03/19/2018 03:38 PM, Chris Wilson wrote: > > Quoting Gustavo A. R. Silva (2018-03-19 19:30:53) > >> _workload_ is being dereferenced before it is null checked, hence > >> there is a potential null pointer dereference. > >> > >> Fix this by moving the pointer dereference after _workload_ has > >> been null checked. > > > > The checks are misleading and not required. > > All of them? > > if (!workload || !reg_state || workload->ring_id != RCS) > return; workload can not be NULL (dereference in caller), reg_state can not be NULL (by construct from kmap()). It may be not an RCS ring through. -Chris
diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c index 0681264..be1a297 100644 --- a/drivers/gpu/drm/i915/gvt/scheduler.c +++ b/drivers/gpu/drm/i915/gvt/scheduler.c @@ -60,9 +60,9 @@ static void set_context_pdp_root_pointer( static void sr_oa_regs(struct intel_vgpu_workload *workload, u32 *reg_state, bool save) { - struct drm_i915_private *dev_priv = workload->vgpu->gvt->dev_priv; - u32 ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset; - u32 ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset; + struct drm_i915_private *dev_priv; + u32 ctx_oactxctrl; + u32 ctx_flexeu0; int i = 0; u32 flex_mmio[] = { i915_mmio_reg_offset(EU_PERF_CNTL0), @@ -77,6 +77,10 @@ static void sr_oa_regs(struct intel_vgpu_workload *workload, if (!workload || !reg_state || workload->ring_id != RCS) return; + dev_priv = workload->vgpu->gvt->dev_priv; + ctx_oactxctrl = dev_priv->perf.oa.ctx_oactxctrl_offset; + ctx_flexeu0 = dev_priv->perf.oa.ctx_flexeu0_offset; + if (save) { workload->oactxctrl = reg_state[ctx_oactxctrl + 1];
_workload_ is being dereferenced before it is null checked, hence there is a potential null pointer dereference. Fix this by moving the pointer dereference after _workload_ has been null checked. Addresses-Coverity-ID: 1430136 ("Dereference before null check") Fixes: fa3dd623e559 ("drm/i915/gvt: keep oa config in shadow ctx") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/gpu/drm/i915/gvt/scheduler.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)