Re: Memory modified after freeing in 2.5.63?

From: Andrew Morton (akpm@digeo.com)
Date: Fri Feb 28 2003 - 16:23:22 EST


Petr Vandrovec <vandrove@vc.cvut.cz> wrote:
>
> Hi,
> for some time I'm using patch attached at the end of this email,
> which modifies check_poison function to not only verify that
> last byte is POISON_END, but also that all preceeding bytes are
> either POISON_BEFORE or POISON_AFTER bytes.

Nice patch.

> And now when I returned from my month vacation and upgraded
> from 2.5.52 to 2.5.63, when dselect/apt updates dozens of packages,
> I'm getting memory corruption reports as shown below - 22nd byte
> in vm_area_struct - which looks like that VM_ACCOUNT in vm_flags
> is set after vma is freeed... Any clue? Setting VM_ACCOUNT
> in mremap.c:move_vma after calling do_unmap() looks suspicious
> to me, but as I know almost nothing about MM...

Ha! I've been harrassing Hugh over this ;)

Thanks.

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This archive was generated by hypermail 2b29 : Fri Feb 28 2003 - 22:00:50 EST