1. 22 Feb, 2014 1 commit
    • Mel Gorman's avatar
      xen: properly account for _PAGE_NUMA during xen pte translations · 1160ce4b
      Mel Gorman authored
      commit a9c8e4be upstream.
      
      Steven Noonan forwarded a users report where they had a problem starting
      vsftpd on a Xen paravirtualized guest, with this in dmesg:
      
        BUG: Bad page map in process vsftpd  pte:8000000493b88165 pmd:e9cc01067
        page:ffffea00124ee200 count:0 mapcount:-1 mapping:     (null) index:0x0
        page flags: 0x2ffc0000000014(referenced|dirty)
        addr:00007f97eea74000 vm_flags:00100071 anon_vma:ffff880e98f80380 mapping:          (null) index:7f97eea74
        CPU: 4 PID: 587 Comm: vsftpd Not tainted 3.12.7-1-ec2 #1
        Call Trace:
          dump_stack+0x45/0x56
          print_bad_pte+0x22e/0x250
          unmap_single_vma+0x583/0x890
          unmap_vmas+0x65/0x90
          exit_mmap+0xc5/0x170
          mmput+0x65/0x100
          do_exit+0x393/0x9e0
          do_group_exit+0xcc/0x140
          SyS_exit_group+0x14/0x20
          system_call_fastpath+0x1a/0x1f
        Disabling lock debugging due to kernel taint
        BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:0 val:-1
        BUG: Bad rss-counter state mm:ffff880e9ca60580 idx:1 val:1
      
      The issue could not be reproduced under an HVM instance with the same
      kernel, so it appears to be exclusive to paravirtual Xen guests.  He
      bisected the problem to commit 1667918b ("mm: numa: clear numa
      hinting information on mprotect") that was also included in 3.12-stable.
      
      The problem was related to how xen translates ptes because it was not
      accounting for the _PAGE_NUMA bit.  This patch splits pte_present to add
      a pteval_present helper for use by xen so both bare metal and xen use
      the same code when checking if a PTE is present.
      
      [mgorman@suse.de: wrote changelog, proposed minor modifications]
      [akpm@linux-foundation.org: fix typo in comment]
      Reported-by: default avatarSteven Noonan <steven@uplinklabs.net>
      Tested-by: default avatarSteven Noonan <steven@uplinklabs.net>
      Signed-off-by: default avatarElena Ufimtseva <ufimtseva@gmail.com>
      Signed-off-by: default avatarMel Gorman <mgorman@suse.de>
      Reviewed-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Acked-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1160ce4b
  2. 20 Feb, 2014 32 commits
  3. 13 Feb, 2014 7 commits