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* [PATCH 5/5] UML - Fix mm_context memory leak
@ 2008-02-06 17:44 Jeff Dike
0 siblings, 0 replies; only message in thread
From: Jeff Dike @ 2008-02-06 17:44 UTC (permalink / raw)
To: Andrew Morton; +Cc: LKML, uml-devel, Miklos Szeredi
[ Spotted by Miklos ]
Fix a memory leak in init_new_context. The struct page ** buffer
allocated for install_special_mapping was never recorded, and thus
leaked when the mm_struct was freed. Fix it by saving the pointer in
mm_context_t and freeing it in arch_exit_mmap.
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
---
arch/um/include/um_mmu.h | 1 +
arch/um/kernel/skas/mmu.c | 5 +++++
2 files changed, 6 insertions(+)
Index: linux-2.6-git/arch/um/include/um_mmu.h
===================================================================
--- linux-2.6-git.orig/arch/um/include/um_mmu.h 2008-02-06 12:15:05.000000000 -0500
+++ linux-2.6-git/arch/um/include/um_mmu.h 2008-02-06 12:24:08.000000000 -0500
@@ -13,6 +13,7 @@
typedef struct mm_context {
struct mm_id id;
struct uml_ldt ldt;
+ struct page **stub_pages;
} mm_context_t;
extern void __switch_mm(struct mm_id * mm_idp);
Index: linux-2.6-git/arch/um/kernel/skas/mmu.c
===================================================================
--- linux-2.6-git.orig/arch/um/kernel/skas/mmu.c 2008-02-06 12:15:05.000000000 -0500
+++ linux-2.6-git/arch/um/kernel/skas/mmu.c 2008-02-06 12:24:31.000000000 -0500
@@ -91,6 +91,8 @@ int init_new_context(struct task_struct
goto out_free;
}
+ to_mm->stub_pages = NULL;
+
return 0;
out_free:
@@ -126,6 +128,7 @@ void arch_dup_mmap(struct mm_struct *old
pages[0] = virt_to_page(&__syscall_stub_start);
pages[1] = virt_to_page(mm->context.id.stack);
+ mm->context.stub_pages = pages;
/* dup_mmap already holds mmap_sem */
err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
@@ -147,6 +150,8 @@ void arch_exit_mmap(struct mm_struct *mm
{
pte_t *pte;
+ if (mm->context.stub_pages != NULL)
+ kfree(mm->context.stub_pages);
pte = virt_to_pte(mm, STUB_CODE);
if (pte != NULL)
pte_clear(mm, STUB_CODE, pte);
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2008-02-06 17:44 [PATCH 5/5] UML - Fix mm_context memory leak Jeff Dike
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