lkml.org 
[lkml]   [2007]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: 2.6.24-rc5-mm1: problems with cat /proc/kpageflags
    Date
    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


    \
     
     \ /
      Last update: 2007-12-21 22:51    [W:4.121 / U:0.028 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site