From: Alex Elder <elder@xxxxxxxxxx>
[ Upstream commit 6c75dc94f2b27fff57b305af9236eea181a00b6c ]
In gsi_trans_pool_init_dma(), the total size of a pool of memory
used for DMA transactions is calculated. However the calculation is
done incorrectly.
For 4KB pages, this total size is currently always more than one
page, and as a result, the calculation produces a positive (though
incorrect) total size. The code still works in this case; we just
end up with fewer DMA pool entries than we intended.
Bjorn Andersson tested booting a kernel with 16KB pages, and hit a
null pointer derereference in sg_alloc_append_table_from_pages(),
descending from gsi_trans_pool_init_dma(). The cause of this was
that a 16KB total size was going to be allocated, and with 16KB
pages the order of that allocation is 0. The total_size calculation
yielded 0, which eventually led to the crash.
Correcting the total_size calculation fixes the problem.
Reported-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
Tested-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
Fixes: 9dd441e4ed57 ("soc: qcom: ipa: GSI transactions")
Reviewed-by: Mark Bloch <mbloch@xxxxxxxxxx>
Signed-off-by: Alex Elder <elder@xxxxxxxxxx>
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230328162751.2861791-1-elder@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ipa/gsi_trans.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ipa/gsi_trans.c b/drivers/net/ipa/gsi_trans.c
index 26b7f683a3e17..fa6863c265eb9 100644
--- a/drivers/net/ipa/gsi_trans.c
+++ b/drivers/net/ipa/gsi_trans.c
@@ -153,7 +153,7 @@ int gsi_trans_pool_init_dma(struct device *dev, struct gsi_trans_pool *pool,
* gsi_trans_pool_exit_dma() can assume the total allocated
* size is exactly (count * size).
*/
- total_size = get_order(total_size) << PAGE_SHIFT;
+ total_size = PAGE_SIZE << get_order(total_size);
virt = dma_alloc_coherent(dev, total_size, &addr, GFP_KERNEL);
if (!virt)
--
2.39.2
