Re: acpi_button: random oops on boot

From: Thomas Renninger
Date: Mon Jan 24 2011 - 08:03:29 EST


On Tuesday, December 07, 2010 06:15:21 AM Bjorn Helgaas wrote:
> On Tue, Dec 07, 2010 at 12:54:59AM +0100, Tobias Karnat wrote:
...
> > Couldn't this be a compiler issue?
> > Adding some printk's to fix it seems to be insane.
>
> Agreed, adding printk's is absolutely not any kind of fix.
> I think it's more likely to be some sort of memory corruption or
> race than a compiler problem. I assume there is some old kernel
> that works fine, even when compiled with the same compiler.
>
> In addition to the isolation ideas I suggested above, you might
> boot with "maxcpus=1" and turn on all the Kconfig memory debug
> switches.
Aren't there some memory corruption checkers which can
additionally be enabled?

CONFIG_DEBUG_SLAB
Say Y here to have the kernel do limited verification on memory
allocation as well as poisoning memory on free to catch use of freed
memory. This can make kmalloc/kfree-intensive workloads much slower.

CONFIG_DEBUG_VM
Enable this to turn on extended checks in the virtual-memory system
that may impact performance.

CONFIG_DEBUG_LIST
Enable this to turn on extended checks in the linked-list
walking routines.

CONFIG_DEBUG_PAGEALLOC
Unmap pages from the kernel linear mapping after free_pages().
This results in a large slowdown, but helps to find certain types
of memory corruption.

Did I oversee one?

Not sure which is best, it should not hurt to turn on all
(if possible) for a test.

Thomas
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