linux-kernel - [PATCH] mm/shmem: initialize folio to NULL

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Date:   Mon,  9 May 2022 08:31:16 -0400
From:   Tom Rix <trix@...hat.com>
To:     hughd@...gle.com, akpm@...ux-foundation.org, nathan@...nel.org,
        ndesaulniers@...gle.com, willy@...radead.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        llvm@...ts.linux.dev, Tom Rix <trix@...hat.com>
Subject: [PATCH] mm/shmem: initialize folio to NULL

The clang build fails with
mm/shmem.c:1704:7: error: variable 'folio' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
  if (!page) {
       ^~~~~
The error handler for !page jumps to an if-check for an unset folio.
So initialize folio to NULL.

Fixes: 2b58b3f33ba2 ("mm/shmem: convert shmem_swapin_page() to shmem_swapin_folio()")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 mm/shmem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 107f1e4dd0aa..7faaa61ff7fa 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1682,7 +1682,7 @@ static int shmem_swapin_folio(struct inode *inode, pgoff_t index,
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	struct mm_struct *charge_mm = vma ? vma->vm_mm : NULL;
 	struct page *page;
-	struct folio *folio;
+	struct folio *folio = NULL;
 	swp_entry_t swap;
 	int error;
 
-- 
2.27.0