um: uml_dup_mmap() relies on ->mmap_sem being held, but activate_mm() doesn't hold it

... while calling uml_dup_mmap()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-02-23 01:37:19 -05:00
parent ea6fb41752
commit ac2aca2817
2 changed files with 10 additions and 3 deletions

View File

@ -9,7 +9,7 @@
#include <linux/sched.h>
#include <asm/mmu.h>
extern void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm);
extern void uml_setup_stubs(struct mm_struct *mm);
extern void arch_exit_mmap(struct mm_struct *mm);
#define deactivate_mm(tsk,mm) do { } while (0)
@ -23,7 +23,9 @@ static inline void activate_mm(struct mm_struct *old, struct mm_struct *new)
* when the new ->mm is used for the first time.
*/
__switch_mm(&new->context.id);
arch_dup_mmap(old, new);
down_write(&new->mmap_sem);
uml_setup_stubs(new);
up_write(&new->mmap_sem);
}
static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
@ -39,6 +41,11 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next,
}
}
static inline void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
{
uml_setup_stubs(mm);
}
static inline void enter_lazy_tlb(struct mm_struct *mm,
struct task_struct *tsk)
{

View File

@ -101,7 +101,7 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
return ret;
}
void arch_dup_mmap(struct mm_struct *oldmm, struct mm_struct *mm)
void uml_setup_stubs(struct mm_struct *mm)
{
struct page **pages;
int err, ret;