linux-kernel - [PATCH] mm: thp: fix a double unlock bug

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Date:   Tue, 1 Jun 2021 12:24:09 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Yang Shi <shy828301@...il.com>
Cc:     Mel Gorman <mgorman@...e.de>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] mm: thp: fix a double unlock bug

We're supposed to be holding the "vmf->ptl" spin_lock when we goto
out_map.  The lock is dropped after if finishes cleaning up.

Fixes: 9aff7b33c74a ("mm: thp: refactor NUMA fault handling")
Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
 mm/huge_memory.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e353bbc6cee3..caa0148f15bb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1465,10 +1465,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
 
 	pmd = pmd_modify(oldpmd, vma->vm_page_prot);
 	page = vm_normal_page_pmd(vma, haddr, pmd);
-	if (!page) {
-		spin_unlock(vmf->ptl);
+	if (!page)
 		goto out_map;
-	}
 
 	/* See similar comment in do_numa_page for explanation */
 	if (!was_writable)
-- 
2.30.2