Re: memory hotplug and force_remove

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Monday, March 20, 2017 03:29:39 PM Michal Hocko wrote:
> Hi Rafael,

Hi,

> we have been chasing the following BUG() triggering during the memory
> hotremove (remove_memory):
> 	ret = walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1), NULL,
> 				check_memblock_offlined_cb);
> 	if (ret)
> 		BUG();
> 
> and it took a while to learn that the issue is caused by
> /sys/firmware/acpi/hotplug/force_remove being enabled. I was really
> surprised to see such an option because at least for the memory hotplug
> it cannot work at all. Memory hotplug fails when the memory is still
> in use. Even if we do not BUG() here enforcing the hotplug operation
> will lead to problematic behavior later like crash or a silent memory
> corruption if the memory gets onlined back and reused by somebody else.
> 
> I am wondering what was the motivation for introducing this behavior and
> whether there is a way to disallow it for memory hotplug. Or maybe drop
> it completely. What would break in such a case?

Honestly, I don't remember from the top of my head and I haven't looked at
that code for several months.

I need some time to recall that.

Thanks,
Rafael

--
To unsubscribe from this list: send the line "unsubscribe linux-api" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux