Re: [bug report] mm,thp: add read-only THP support for (non-shmem) FS

[Song Liu <songliubraving@xxxxxx>]

+ Andrew

> On Aug 9, 2019, at 5:34 AM, Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
> 
> Hello Song Liu,
> 
> The patch 89e1c65c0db7: "mm,thp: add read-only THP support for
> (non-shmem) FS" from Aug 7, 2019, leads to the following static
> checker warning:
> 
> 	mm/khugepaged.c:1532 collapse_file()
> 	error: double unlock 'irq:'
> 
[...]

Thanks Dan! The following patch fixes this issue. 

Hi Andrew, could you please add this fix to the mm tree?

Thanks,
Song


================= 8< ======================

>From 30fd3683bb62cb81bb144e945edb768aff7ca445 Mon Sep 17 00:00:00 2001
From: Song Liu <songliubraving@xxxxxx>
Date: Fri, 9 Aug 2019 07:15:17 -0700
Subject: [PATCH] khugepaged: fix double unlock in collapse_file()

In collapse_file, when try_to_release_page() fails, we need to goto
out_unlock, because we already called xas_unlock_irq().

Fixes: 89e1c65c0db7 ("mm,thp: add read-only THP support for (non-shmem) FS")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
 mm/khugepaged.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 40c25ddf29e4..f3b94a5a9c43 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1472,7 +1472,7 @@ static void collapse_file(struct mm_struct *mm,
                if (page_has_private(page) &&
                    !try_to_release_page(page, GFP_KERNEL)) {
                        result = SCAN_PAGE_HAS_PRIVATE;
-                       break;
+                       goto out_unlock;
                }

                if (page_mapped(page))
--
2.17.1