Messages in this thread Patch in this message | | | Date | Mon, 12 Jan 2009 14:59:39 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH]Fix: 32bit binary has 64bit address of stack vma |
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On Mon, 5 Jan 2009 15:39:07 -0800 Ying Han <yinghan@google.com> wrote:
> From: Ying Han <yinghan@google.com> > > Fix 32bit binary get 64bit stack vma offset. > > 32bit binary running on 64bit system, the /proc/pid/maps shows for the > vma represents stack get a 64bit adress: > ff96c000-ff981000 rwxp 7ffffffea000 00:00 0 [stack] > > Signed-off-by: Ying Han <yinghan@google.com> > > fs/exec.c | 5 +- > > diff --git a/fs/exec.c b/fs/exec.c > index 4e834f1..8c3eff4 100644 > --- a/fs/exec.c > +++ b/fs/exec.c > @@ -517,6 +517,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, uns > unsigned long length = old_end - old_start; > unsigned long new_start = old_start - shift; > unsigned long new_end = old_end - shift; > + unsigned long new_pgoff = new_start >> PAGE_SHIFT; > struct mmu_gather *tlb; > > BUG_ON(new_start > new_end); > @@ -531,7 +532,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, uns > /* > * cover the whole range: [new_start, old_end) > */ > - vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); > + vma_adjust(vma, new_start, old_end, new_pgoff, NULL); > > /* > * move the page tables downwards, on failure we rely on > @@ -564,7 +565,7 @@ static int shift_arg_pages(struct vm_area_struct *vma, uns > /* > * shrink the vma to just the new range. > */ > - vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); > + vma_adjust(vma, new_start, new_end, new_pgoff, NULL); > > return 0;
I rewrote the chagnelog as below. Please confirm that it makes sense?
Subject: fs/exec.c: fix value of vma->vm_pgoff for the stack VMA of 32-bit processes From: Ying Han <yinghan@google.com>
With a 32 bit binary running on a 64 bit system, the /proc/pid/maps for the [stack] VMA displays a 64-bit address:
ff96c000-ff981000 rwxp 7ffffffea000 00:00 0 [stack]
This is because vma->vm_pgoff for that VMA is incorrectly being stored in units of offset-in-bytes. It should be stored in units of offset-in-pages.
Signed-off-by: Ying Han <yinghan@google.com> Cc: Mike Waychison <mikew@google.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
fs/exec.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff -puN fs/exec.c~fs-execc-fix-value-of-vma-vm_pgoff-for-the-stack-vma-of-32-bit-processes fs/exec.c --- a/fs/exec.c~fs-execc-fix-value-of-vma-vm_pgoff-for-the-stack-vma-of-32-bit-processes +++ a/fs/exec.c @@ -509,6 +509,7 @@ static int shift_arg_pages(struct vm_are unsigned long length = old_end - old_start; unsigned long new_start = old_start - shift; unsigned long new_end = old_end - shift; + unsigned long new_pgoff = new_start >> PAGE_SHIFT; struct mmu_gather *tlb; BUG_ON(new_start > new_end); @@ -523,7 +524,7 @@ static int shift_arg_pages(struct vm_are /* * cover the whole range: [new_start, old_end) */ - vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL); + vma_adjust(vma, new_start, old_end, new_pgoff, NULL); /* * move the page tables downwards, on failure we rely on @@ -556,7 +557,7 @@ static int shift_arg_pages(struct vm_are /* * shrink the vma to just the new range. */ - vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL); + vma_adjust(vma, new_start, new_end, new_pgoff, NULL); return 0; } _
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