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Commit ac2aca28 authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent ea6fb417

arch/um/include/asm/mmu_context.h

+9 −2
Original line number Diff line number Diff line
@@ -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)

{

arch/um/kernel/skas/mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -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;