Messages in this thread | | | Subject | Re: Current bk on ppc32: kernel text corruption | From | Benjamin Herrenschmidt <> | Date | Sun, 20 Feb 2005 10:32:12 +1100 |
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On Fri, 2005-02-18 at 18:09 +1100, Benjamin Herrenschmidt wrote: > Ok, we may not be over with memory corruption bugs yet. ppc64 now seem > stable running LTP overnight, but my laptop has a page of kernel .text > replaced with zero's as soon as I launch X (and just X, no need to launc > the whole desktop environment). > > I suspect remap_pfn_range() but I haven't checked yet.
Ok, I found it. It's a bug that was there forever it seems, where radeonfb accel ops may corrupt kernel memory (via bus master from the radeon chip) when switching back from X, due to X remapping some areas of the card vs. fbcon calling some radeonfb accel ops before radeonfb has a chance to re-initialize the chip (when switching back from X).
I'm cooking a workaround patch for 2.6.11, will be ready as soon as I have tested. Proper fix is to make sure fbcon never calls any fbdev accel op before the chip has been properly restored (by a set_var call), but that is beyond the scope of 2.6.11 I suppose...
Ben.
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