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* [PATCH] parisc: mm: Fix a memory leak related to pmd not attached to the pgd
@ 2015-07-13  9:32 ` Christophe JAILLET
  0 siblings, 0 replies; 14+ messages in thread
From: Christophe JAILLET @ 2015-07-13  9:32 UTC (permalink / raw)
  To: jejb, deller, mpatocka, kirill.shutemov
  Cc: linux-parisc, linux-kernel, kernel-janitors, Christophe JAILLET

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

^ permalink raw reply related	[flat|nested] 14+ messages in thread

end of thread, other threads:[~2015-07-20 19:28 UTC | newest]

Thread overview: 14+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-07-13  9:32 [PATCH] parisc: mm: Fix a memory leak related to pmd not attached to the pgd Christophe JAILLET
2015-07-13  9:32 ` Christophe JAILLET
2015-07-13  9:46 ` Kirill A. Shutemov
2015-07-13  9:46   ` Kirill A. Shutemov
2015-07-13 12:48 ` Mikulas Patocka
2015-07-13 12:48   ` Mikulas Patocka
2015-07-13 18:52 ` Helge Deller
2015-07-13 18:52   ` Helge Deller
     [not found]   ` <55A4095E.4060200@gmx.de>
2015-07-14 11:52     ` John David Anglin
2015-07-14 12:01       ` John David Anglin
2015-07-20 19:28   ` Meelis Roos
2015-07-20 19:28     ` Meelis Roos
2015-07-14 11:09 ` Dan Carpenter
2015-07-14 11:09   ` Dan Carpenter

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