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authorJeff Dike <jdike@addtoit.com>2008-02-08 04:22:11 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 09:22:43 -0800
commitac2a659968f5318a180213f0409c2ea21f072820 (patch)
tree2bebff50071f9f9fef802d2434de951e9c235332 /arch/um
parent5aaf5f7b871abf00fb2525e7ed2d5938a74ce23c (diff)
uml: fix mm_context memory leak
[ 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/include/um_mmu.h1
-rw-r--r--arch/um/kernel/skas/mmu.c5
2 files changed, 6 insertions, 0 deletions
diff --git a/arch/um/include/um_mmu.h b/arch/um/include/um_mmu.h
index 82865fcf6872..f575ff91f2a0 100644
--- a/arch/um/include/um_mmu.h
+++ b/arch/um/include/um_mmu.h
@@ -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);
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 78b3e9f69d57..0cd9a7a05e77 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -91,6 +91,8 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
goto out_free;
}
+ to_mm->stub_pages = NULL;
+
return 0;
out_free:
@@ -126,6 +128,7 @@ void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
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);