Re: Laptop mode causing writes to wrong sectors?

From: Bart Samwel
Date: Sat Nov 19 2005 - 18:32:25 EST

Jan Niehusmann wrote:
Question is, could this bug cause filesystem corruption without any Oops
visible in the kernel log? Cc: to Zhu Yi at Intel - can you answer this

OK, can this bug overwrite a page containing filesystem metadata? The way it looks to me, it can: it writes at some fixed distance after a block of memory allocated by the driver, and that memory could probably be anything.

Now, can the stuff go to disk without oopsing? In the case of ext3, the metadata writeback is handled by the JBD layer, which is block-based and doesn't care about the actual page contents AFAIK -- that's handled by the ext3 filesystem layer. That means a corrupted metadata page can go to disk without oopsing. Youch. :/

Remaining issue: this bug is only triggered when the ipw2200 driver does firmware restarts, which generates kernel output "ipw2200: Firmware error detected. Restarting". Jan, Bradley, do you see any of these messages in your logs near the time of corruption? That should be within 10 minutes before it; the corruption may happen anywhere during a spun-down period. (Or does the ipw2200 driver only show this message in debug mode?)

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