FAILED: patch "[PATCH] iommu/io-pgtable-arm-v7s: Add error handle for page table" failed to apply to 4.19-stable tree

The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a556cfe4cabc6d79cbb7733f118bbb420b376fe6 Mon Sep 17 00:00:00 2001
From: Yunfei Wang <[email protected]>
Date: Tue, 7 Dec 2021 19:33:15 +0800
Subject: [PATCH] iommu/io-pgtable-arm-v7s: Add error handle for page table
allocation failure

In __arm_v7s_alloc_table function:
iommu call kmem_cache_alloc to allocate page table, this function allocate memory may fail, when kmem_cache_alloc fails to allocate table, call virt_to_phys will be abnomal and return unexpected phys and goto out_free, then call kmem_cache_free to release table will trigger KE, __get_free_pages and free_pages have similar problem, so add error handle for page table allocation failure.

index bfb6acb651e5..be066c1503d3 100644
@@ -246,13 +246,17 @@ static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp,
 			__GFP_ZERO | ARM_V7S_TABLE_GFP_DMA, get_order(size));
 	else if (lvl == 2)
 		table = kmem_cache_zalloc(data->l2_tables, gfp);
+
+	if (!table)
+		return NULL;
+
 	phys = virt_to_phys(table);
 	if (phys != (arm_v7s_iopte)phys) {
 		/* Doesn't fit in PTE */
 		dev_err(dev, "Page table does not fit in PTE: %pa", &phys);
 		goto out_free;
 	}
-	if (table && !cfg->coherent_walk) {
+	if (!cfg->coherent_walk) {
 		dma = dma_map_single(dev, table, size, DMA_TO_DEVICE);
 		if (dma_mapping_error(dev, dma))
 			goto out_free;