[PATCH] parisc: mm: Fix a memory leak related to pmd not attached to the pgd

Christophe JAILLET
2015-07-13T09:33:09Z

Commit 0e0da48dee8d ("parisc: mm: don't count preallocated pmds")
introduced a memory leak.

After this commit, the 'return' statement in pmd_free is executed in all
cases. Even for pmd that are not attached to the pgd.
So 'free_pages' can never be called anymore, leading to a memory leak.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
This patch is *untested* as I don't have the hardware to test it.

This is just a guess based on the indentation, the comment in the code
and the commit log.
---
arch/parisc/include/asm/pgalloc.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/parisc/include/asm/pgalloc.h b/arch/parisc/include/asm/pgalloc.h
index 3a08eae..f66d3738 100644
--- a/arch/parisc/include/asm/pgalloc.h
+++ b/arch/parisc/include/asm/pgalloc.h
@@ -72,7 +72,7 @@ static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long address)

static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
{
- if(pmd_flag(*pmd) & PxD_FLAG_ATTACHED)
+ if (pmd_flag(*pmd) & PxD_FLAG_ATTACHED) {
/*
* This is the permanent pmd attached to the pgd;
* cannot free it.
@@ -81,6 +81,7 @@ static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)
*/
mm_inc_nr_pmds(mm);
return;
+ }
free_pages((unsigned long)pmd, PMD_ORDER);
}

--
2.1.4