[PATCH 5.10/5.15 3/3] ntb: Store original DMA address for future release

[Mikhail Dmitrichenko <mdmitrichenko@astralinux.ru>]

From: Leon Romanovsky <leonro@nvidia.com>

commit da6d997ac556479c112554ab5d95cbd04683eb11 upstream.

The DMA API requires that dma_free_attrs receive the exact dma_handle
originally returned by the allocation function. Do not modify it.

Fixes: fc5d1829f9bf ("NTB: transport: Try harder to alloc an aligned MW buffer")
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260501-dma-attrs-debug-v2-1-8dbac75cd501@nvidia.com
Signed-off-by: Mikhail Dmitrichenko <mdmitrichenko@astralinux.ru>
---
Backport fix for CVE-2026-80884.

 drivers/ntb/ntb_transport.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c
index 2fca53b8e486d..fd3af0058f08c 100644
--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -211,6 +211,7 @@ struct ntb_transport_mw {
 	void *alloc_addr;
 	void *virt_addr;
 	dma_addr_t dma_addr;
+	dma_addr_t original_dma_addr;
 };
 
 struct ntb_transport_client_dev {
@@ -800,7 +801,7 @@ static void ntb_free_mw(struct ntb_transport_ctx *nt, int num_mw)
 
 	ntb_mw_clear_trans(nt->ndev, PIDX, num_mw);
 	dma_free_coherent(dma_dev, mw->alloc_size,
-			  mw->alloc_addr, mw->dma_addr);
+			  mw->alloc_addr, mw->original_dma_addr);
 	mw->xlat_size = 0;
 	mw->buff_size = 0;
 	mw->alloc_size = 0;
@@ -823,6 +824,7 @@ static int ntb_alloc_mw_buffer(struct ntb_transport_mw *mw,
 		return -ENOMEM;
 	}
 	virt_addr = alloc_addr;
+	mw->original_dma_addr = dma_addr;
 
 	/*
 	 * we must ensure that the memory address allocated is BAR size
-- 
2.43.0