Hello Chris Wilson,
The patch eb5c10cbbc2f: "drm/i915: Remove I915_USER_PRIORITY_SHIFT"
from Jan 20, 2021, leads to the following Smatch static checker
warning:
drivers/gpu/drm/i915/gt/selftest_execlists.c:1544 live_busywait_preempt() error: 'ctx_hi' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:1549 live_busywait_preempt() error: 'ctx_lo' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:1740 live_preempt() error: 'ctx_hi' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:1745 live_preempt() error: 'ctx_lo' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:1844 live_late_preempt() error: 'ctx_lo' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:1871 live_late_preempt() error: 'ctx_hi' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:3382 live_preempt_timeout() error: 'ctx_hi' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c:3387 live_preempt_timeout() error: 'ctx_lo' dereferencing possible ERR_PTR()
drivers/gpu/drm/i915/gt/selftest_execlists.c
1525 static int live_busywait_preempt(void *arg)
1526 {
1527 struct intel_gt *gt = arg;
1528 struct i915_gem_context *ctx_hi, *ctx_lo;
1529 struct intel_engine_cs *engine;
1530 struct drm_i915_gem_object *obj;
1531 struct i915_vma *vma;
1532 enum intel_engine_id id;
1533 int err = -ENOMEM;
1534 u32 *map;
1535
1536 /*
1537 * Verify that even without HAS_LOGICAL_RING_PREEMPTION, we can
1538 * preempt the busywaits used to synchronise between rings.
1539 */
1540
1541 ctx_hi = kernel_context(gt->i915, NULL);
1542 if (!ctx_hi)
^^^^^^^
kernel_context() returns error pointers.
1543 return -ENOMEM;
--> 1544 ctx_hi->sched.priority = I915_CONTEXT_MAX_USER_PRIORITY;
1545
1546 ctx_lo = kernel_context(gt->i915, NULL);
1547 if (!ctx_lo)
^^^^^^^
Same.
It's so weird that I'm getting this warning and today I can't compile
this file... Plus I'm supposed to be on an ARM config... Something is
wrong with my setup. But the warnings looks correct.
1548 goto err_ctx_hi;
1549 ctx_lo->sched.priority = I915_CONTEXT_MIN_USER_PRIORITY;
1550
1551 obj = i915_gem_object_create_internal(gt->i915, PAGE_SIZE);
1552 if (IS_ERR(obj)) {
1553 err = PTR_ERR(obj);
1554 goto err_ctx_lo;
1555 }
1556
regards,
dan carpenter
