1. 14 2月, 2013 38 次提交
  2. 13 2月, 2013 2 次提交
    • M
      x86/mm: Check if PUD is large when validating a kernel address · 0ee364eb
      Mel Gorman 提交于
      A user reported the following oops when a backup process reads
      /proc/kcore:
      
       BUG: unable to handle kernel paging request at ffffbb00ff33b000
       IP: [<ffffffff8103157e>] kern_addr_valid+0xbe/0x110
       [...]
      
       Call Trace:
        [<ffffffff811b8aaa>] read_kcore+0x17a/0x370
        [<ffffffff811ad847>] proc_reg_read+0x77/0xc0
        [<ffffffff81151687>] vfs_read+0xc7/0x130
        [<ffffffff811517f3>] sys_read+0x53/0xa0
        [<ffffffff81449692>] system_call_fastpath+0x16/0x1b
      
      Investigation determined that the bug triggered when reading
      system RAM at the 4G mark. On this system, that was the first
      address using 1G pages for the virt->phys direct mapping so the
      PUD is pointing to a physical address, not a PMD page.
      
      The problem is that the page table walker in kern_addr_valid() is
      not checking pud_large() and treats the physical address as if
      it was a PMD.  If it happens to look like pmd_none then it'll
      silently fail, probably returning zeros instead of real data. If
      the data happens to look like a present PMD though, it will be
      walked resulting in the oops above.
      
      This patch adds the necessary pud_large() check.
      
      Unfortunately the problem was not readily reproducible and now
      they are running the backup program without accessing
      /proc/kcore so the patch has not been validated but I think it
      makes sense.
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Reviewed-by: NRik van Riel <riel@redhat.coM>
      Reviewed-by: NMichal Hocko <mhocko@suse.cz>
      Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
      Cc: stable@vger.kernel.org
      Cc: linux-mm@kvack.org
      Link: http://lkml.kernel.org/r/20130211145236.GX21389@suse.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
      0ee364eb
    • L
      Merge branch 'autofs-fix' of... · ecf223fc
      Linus Torvalds 提交于
      Merge branch 'autofs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux into akpm
      
      Pull hp parisc automounter fix from Helge Deller:
       "This unbreaks automounter support for the parisc architecture (and
        probably aarch64 as well).""
      
      * 'autofs-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
        unbreak automounter support on 64-bit kernel with 32-bit userspace (v2)
      ecf223fc