Commit 4c4ac9a4 authored Jul 13, 2015 by Christophe Jaillet Committed by Helge Deller Jul 19, 2015

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



Commit 0e0da48d ("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>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org  # v4.0+
Signed-off-by: Helge Deller <deller@gmx.de>

parent 9d37e667

arch/parisc/include/asm/pgalloc.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);
		}

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