From ebe162db655881a38de43301151ff7ac940602b5 Mon Sep 17 00:00:00 2001 From: Krzysztof Karas Date: Fri, 11 Sep 2026 06:11:45 +0000 Subject: [PATCH 1/2] drm/i915/gem: Prevent overstepping exec array boundary It is possible for eb_relocate_parse_slow() to call kvfree() on entries outside the original exec array during following scenario inside eb_relocate_parse_slow(): 1) eb_copy_relocations() allocates as many as eb->buffer_count copies for exec entries; 2) eb_parse() appends up to two VMAs, right after incrementing eb->buffer_count; 3) cleanup under "out" label uses this incremented buffer_count to release relocation pointers from exec array via kvfree(), not from VMA array. To amend this problem, ensure that relocation cleanup uses the original exec object count, excluding the VMAs appended by the command parser. Fixes: 8e4ba491b0ba ("drm/i915: Parse command buffer earlier in eb_relocate(slow)") Signed-off-by: Krzysztof Karas Assisted-by: GitHub-Copilot:gpt-6-astra Cc: stable@vger.kernel.org # 5.10+ Reviewed-by: Andi Shyti Signed-off-by: Andi Shyti Link: https://patch.msgid.link/20260911061145.3535489-1-krzysztof.karas@intel.com (cherry picked from commit 2a0158925fb943c7ba8f3216e2734952128defc9) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c index 1f303d4eaa4d..d5aadced7da0 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c @@ -1766,6 +1766,7 @@ static int eb_reinit_userptr(struct i915_execbuffer *eb) static noinline int eb_relocate_parse_slow(struct i915_execbuffer *eb) { + const unsigned int count = eb->buffer_count; bool have_copy = false; struct eb_vma *ev; int err = 0; @@ -1868,7 +1869,6 @@ err: out: if (have_copy) { - const unsigned int count = eb->buffer_count; unsigned int i; for (i = 0; i < count; i++) { From 5346b1cec6afa4f9b4b49a9f84e3cfef95a3f7bb Mon Sep 17 00:00:00 2001 From: Krzysztof Karas Date: Thu, 10 Sep 2026 08:13:29 +0000 Subject: [PATCH 2/2] drm/i915/gt: Unmask interrupts only when ACTIVE is true There is a small race window between intel_rps_boost() reading a stale ACTIVE state and queuing rps->work, where ACTIVE may be changed via asynchronous calls triggered by wakeref drop. This means that rps_work() could be triggered after the GT has been parked, so unmasking RPS PM interrupts would happen without holding PM wakelock. This sequence of events may be observed during live_rc6_ctx_wa() selftest: 1) live_rc6_ctx_wa() -> intel_engine_pm_put() -> wakeref_put() ASYNC1) wakeref_put() callback -> __engine_park() -> intel_gt_pm_put_async() -> intel_gt_pm_put_async_untracked() -> intel_wakeref_put_async() ASYNC2) wakeref_put_async() callback -> __gt_park() -> intel_rps_park() -> intel_rps_clear_active() [clear ACTIVE] WITH INTERRUPTS: -> rps_disable_interrupts() -> cancel_work_sync(rps->work) -> rps_reset_interrupts() [rps->pm_iir = 0] WITHOUT INTERRUPTS (TIMER mode): -> rps_stop_timer() -> cancel_work_sync(rps->work) 2) live_rc6_ctx_wa() -> intel_gt_wait_for_idle() -> intel_gt_retire_requests_timeout() -> dma_fence_wait_timeout() -> ops->wait() [i915_fence_wait()] -> i915_request_wait_timeout() -> intel_rps_boost() -> intel_rps_is_active() [check ACTIVE] [OPEN RACE WINDOW] -> queue_work(rps->work) -> retire_requests() -> i915_request_retire() -> intel_rps_dec_waiters() [from 1 to 0] If ASYNC1 and ASYNC2 would execute during [OPEN RACE WINDOW], then: 3) rps_work() executes from the workqueue and may satisfy "(!pm_iir && !client_boost)" test (in TIMER mode rps->pm_iir is zeroed by an earlier rps_work() call or never gets a new value after previous intel_rps_unpark() event), so it jumps to "out" label, bypassing intel_rps_is_active() guard and executes gen6_gt_pm_unmask_irq(); 4) GT is parked and runtime PM wakelock is dropped, so only a raw reference in __gt_park() -> intel_display_power_put_async() remains for 100ms, then the MMIO write in gen6_gt_pm_unmask_irq() detects missing wakelock via assert_rpm_wakelock_held() and emits "RPM wakelock ref not held during HW access" tainting kernel. Commit 3e7abf814193 ("drm/i915: Extract GT render power state management") dropped the "if (rps->interrupts_enabled)" guard that gen6_pm_rps_work() had around this unmask in i915_irq.c. INTEL_RPS_ACTIVE brackets the same window, since it is set in intel_rps_unpark() before rps_enable_interrupts() and rps_start_timer() and cleared in intel_rps_park() before rps_stop_timer() and rps_disable_interrupts(). Skip unmasking when RPS is no longer active (reaching unmask operation is independent of INTERRUPT mode). This does not prevent RPS operation from resuming on the next unpark. In interrupt mode, intel_rps_unpark() calls rps_enable_interrupts(), which enables and unmasks the PM interrupts. In timer mode, it calls rps_start_timer(), restarting periodic engine-busyness evaluation. The timer generates software RPS events and queues rps_work() directly, independently of PM interrupt delivery. Neither mode requires the late worker to unmask interrupts while the GT is parked Fixes: 3e7abf814193 ("drm/i915: Extract GT render power state management") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/16562 Cc: stable@vger.kernel.org # v5.5+ Assisted-by: GitHub-Copilot:claude-opus-5 Assisted-by: GitHub-Copilot:gpt-6-astra Signed-off-by: Krzysztof Karas Reviewed-by: Andi Shyti Signed-off-by: Andi Shyti Link: https://patch.msgid.link/20260910081329.3300417-1-krzysztof.karas@intel.com (cherry picked from commit ca4a6deadad15b91ee083afe445fa6bdbfb68206) Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/gt/intel_rps.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/gt/intel_rps.c b/drivers/gpu/drm/i915/gt/intel_rps.c index a33b19c04737..0f9b4f1dd3cb 100644 --- a/drivers/gpu/drm/i915/gt/intel_rps.c +++ b/drivers/gpu/drm/i915/gt/intel_rps.c @@ -1904,7 +1904,8 @@ static void rps_work(struct work_struct *work) out: spin_lock_irq(gt->irq_lock); - gen6_gt_pm_unmask_irq(gt, rps->pm_events); + if (intel_rps_is_active(rps)) + gen6_gt_pm_unmask_irq(gt, rps->pm_events); spin_unlock_irq(gt->irq_lock); }