Messages in this thread | | | From | Mariusz Kozlowski <> | Subject | Re: 2.6.24-rc5-mm1: problems with cat /proc/kpageflags | Date | Fri, 21 Dec 2007 22:51:45 +0100 |
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Hello,
> > > [ 145.128915] TSTATE: 0000004411009603 TPC: 00000000005119ac TNPC: 00000000005119b0 Y: 00000000 Not tainted > > > [ 145.128940] TPC: <kpagecount_read+0x94/0xe0> > > > > My suspicion at this point is that with certain RAM layouts, simply > > iterating over PFN's is simply not working out. > > That was my original suspicion, which is why I asked Mariusz to > effectively comment out the actual PFN lookup up-thread. I didn't send > him a patch to do that, so I guess my instructions on how to hack it > may have been misunderstood.
No. I just made a trivial mistake :-/ Sorry for confusion. I guess I need to verify things three times before sending an email next time.
> > pfn_to_page() seems to be doing no range checking, and with sparsemem > > vmemmap, which sparc64 always uses, this can be problematic. > > > > It just blindly goes "vmemmap + pfn" which is asking for trouble, in > > particular when the physical RAM layout really is sparse. > > > > Maybe it's enough to add a pfn_valid() check here? If pfn_valid() > > means there is a vmemmap translation setup for that page struct too, > > it would work. > > Here's a test patch:
Tested on 2.6.23 and 2.6.24-rc5-mm1. The patch fixes the bug.
Thanks a lot to both of you.
Mariusz
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