[RFC 1/1] swiotlb: Replace BUG_ON() with graceful error handling

[Brian Johannesmeyer <bjohannesmeyer@gmail.com>]

Replace the BUG_ON() assertion in swiotlb_release_slots() with a
conditional check and return. This change prevents a corrupted tlb_addr
from causing a kernel panic.

Co-developed-by: Raphael Isemann <teemperor@gmail.com>
Signed-off-by: Raphael Isemann <teemperor@gmail.com>
Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
---
 kernel/dma/swiotlb.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index aa0a4a220719..54b4f9665772 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -834,7 +834,11 @@ static void swiotlb_release_slots(struct device *dev, phys_addr_t tlb_addr)
 	 * While returning the entries to the free list, we merge the entries
 	 * with slots below and above the pool being returned.
 	 */
-	BUG_ON(aindex >= mem->nareas);
+	if (unlikely(aindex >= mem->nareas)) {
+		dev_err(dev, "%s: invalid area index (%d >= %d)\n", __func__,
+			aindex, mem->nareas);
+		return;
+	}
 
 	spin_lock_irqsave(&area->lock, flags);
 	if (index + nslots < ALIGN(index + 1, IO_TLB_SEGSIZE))
-- 
2.34.1