Re: Ambigiuous thread stack annotation in /proc/pid/[s]maps

From: Siddhesh Poyarekar
Date: Wed Jun 26 2013 - 12:35:47 EST


On 26 June 2013 17:13, Jan Glauber <jan.glauber@xxxxxxxxx> wrote:
> Any ideas how that can be fixed? The only solution that comes to my mind
> is to prevent merging vma's that are used for thread stacks. There is already a
> flag (MAP_STACK) which is set by the libc for mmap'ing thread stacks but the
> kernel currently does not care. If the kernel gets an mmap request with
> MAP_STACK set we could mark the VMA and avoid merging it with others.
>
> Unfortunately there seems to be no bit left in the vm_flags to store the
> MAP_STACK information...

The annotations essentially point out that the vma contains the stack
and not that the vma *is* the stack. We'd get similar output with
makecontext/getcontext, where the stack may just be a portion of
memory in another vma. I don't remember if I had explicitly mentioned
that during the original discussion.

Siddhesh
--
http://siddhesh.in
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/