Forwarded: [PATCH] iommufd: Initialize batch->kind in batch_clear()

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Subject: [PATCH] iommufd: Initialize batch->kind in batch_clear()
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

KMSAN reported an uninitialized value when batch_add_pfn_num() reads
batch->kind. This occurs because batch_clear() does not initialize
the kind field, leaving it with garbage data when a struct pfn_batch
is declared on the stack.

When batch_add_pfn_num() checks "if (batch->kind != kind)", it reads
this uninitialized value, triggering KMSAN warnings.

Initialize batch->kind to zero in batch_clear() to ensure the field
always starts in a known state.

Reported-by: syzbot+df28076a30d726933015@syzkaller.appspotmail.com
Signed-off-by: Deepanshu Kartikey <kartikey406@gmail.com>
---
 drivers/iommu/iommufd/pages.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index dbe51ecb9a20..f606148920fa 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -289,6 +289,7 @@ static void batch_clear(struct pfn_batch *batch)
 	batch->end = 0;
 	batch->pfns[0] = 0;
 	batch->npfns[0] = 0;
+	batch->kind = 0;
 }
 
 /*
-- 
2.43.0