On 16.01.2025 11:40, Krzysztof Karas wrote:
spin_lock/unlock() functions used in interrupt contexts could result in a deadlock, as seen in GitLab issue #13399: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13399, which occurs when interrupt comes in while holding a lock. Try to remedy the problem by saving irq state before spin lock acquisition. v2: add irqs' state save/restore calls to all locks/unlocks in signal_irq_work() execution (Maciej) v3: use with spin_lock_irqsave() in guc_lrc_desc_unpin() instead of other lock/unlock calls and add Fixes and Cc tags (Tvrtko); change title and commit message Signed-off-by: Krzysztof Karas <krzysztof.karas@xxxxxxxxx> Fixes: 2f2cc53b5fe7 ("drm/i915/guc: Close deregister-context race against CT-loss") Cc: <stable@xxxxxxxxxxxxxxx> # v6.9+ --- drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c index 12f1ba7ca9c1..29d9c81473cc 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c @@ -3433,10 +3433,10 @@ static inline int guc_lrc_desc_unpin(struct intel_context *ce) */ ret = deregister_context(ce, ce->guc_id.id); if (ret) { - spin_lock(&ce->guc_state.lock); + spin_lock_irqsave(&ce->guc_state.lock, flags); set_context_registered(ce); clr_context_destroyed(ce); - spin_unlock(&ce->guc_state.lock); + spin_unlock_irqrestore(&ce->guc_state.lock, flags); /* * As gt-pm is awake at function entry, intel_wakeref_put_async merely decrements * the wakeref immediately but per function spec usage call this after unlock.
Looked at this and wasn't seeing it. There is spin_lock_irqsave() used earlier.
Reviewed-by: Maciej Patelczyk <maciej.patelczyk@xxxxxxxxx>
