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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>
hifive-unleashed-5.1
Jeff Dike 2008-02-08 04:22:11 -08:00 committed by Linus Torvalds
parent 5aaf5f7b87
commit ac2a659968
2 changed files with 6 additions and 0 deletions
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1
arch/um/include/um_mmu.h
View File

@ -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);

5
arch/um/kernel/skas/mmu.c
View File

@ -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);