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