Commit 73219d17 authored Jun 21, 2005 by Chris Wright Committed by Linus Torvalds Jun 21, 2005

[PATCH] mmap topdown fix for large stack limit, large allocation



The topdown changes in 2.6.12-rc1 can cause large allocations with large
stack limit to fail, despite there being space available.  The
mmap_base-len is only valid when len >= mmap_base.  However, nothing in
topdown allocator checks this.  It's only (now) caught at higher level,
which will cause allocation to simply fail.  The following change restores
the fallback to bottom-up path, which will allow large allocations with
large stack limit to potentially still succeed.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 1363c3cd

mm/mmap.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1267,6 +1267,9 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
		return (mm->free_area_cache = addr-len);
		}

		if (mm->mmap_base < len)
		goto bottomup;

		addr = mm->mmap_base-len;

		do {
		@@ -1288,6 +1291,7 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
		addr = vma->vm_start-len;
		} while (len < vma->vm_start);

		bottomup:
		/*
		* A failed mmap() very likely causes application failure,
		* so fall back to the bottom-up function here. This scenario