x86 get_unmapped_area: Access mmap_legacy_base through mm_struct member (41aacc1e) · Commits · 戴 / test

This is the updated version of ("x86 get_unmapped_area(): use proper mmap base for bottom-up direction") that only randomizes the mmap base address once. Signed-off-by:

Radu Caragea <sinaelgl@gmail.com> Reported-and-tested-by:

Jeff Shorey <shoreyjeff@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Michel Lespinasse <walken@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Adrian Sendroiu <molecula2788@gmail.com> Cc: Greg KH <greg@kroah.com> Cc: Kamal Mostafa <kamal@canonical.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/kernel/sys_x86_64.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -101,7 +101,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
		*begin = new_begin;
		}
		} else {
		*begin = TASK_UNMAPPED_BASE;
		*begin = current->mm->mmap_legacy_base;
		*end = TASK_SIZE;
		}
		}

arch/x86/mm/mmap.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -112,11 +112,13 @@ static unsigned long mmap_legacy_base(void)
		*/
		void arch_pick_mmap_layout(struct mm_struct *mm)
		{
		mm->mmap_legacy_base = mmap_legacy_base();
		mm->mmap_base = mmap_base();

		if (mmap_is_legacy()) {
		mm->mmap_base = mmap_legacy_base();
		mm->mmap_base = mm->mmap_legacy_base;
		mm->get_unmapped_area = arch_get_unmapped_area;
		} else {
		mm->mmap_base = mmap_base();
		mm->get_unmapped_area = arch_get_unmapped_area_topdown;
		}
		}

include/linux/mm_types.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -332,6 +332,7 @@ struct mm_struct {
		unsigned long pgoff, unsigned long flags);
		#endif
		unsigned long mmap_base; /* base of mmap area */
		unsigned long mmap_legacy_base; /* base of mmap area in bottom-up allocations */
		unsigned long task_size; /* size of task vm space */
		unsigned long highest_vm_end; /* highest vma end address */
		pgd_t * pgd;

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