1. 22 2月, 2009 12 次提交
  2. 21 2月, 2009 26 次提交
  3. 20 2月, 2009 2 次提交
    • C
      Btrfs: check file pointer in btrfs_sync_file · 2cfbd50b
      Chris Mason 提交于
      fsync can be called by NFS with a null file pointer, and btrfs was
      oopsing in this case.
      Signed-off-by: NChris Mason <chris.mason@oracle.com>
      2cfbd50b
    • I
      x86: use the right protections for split-up pagetables · 07a66d7c
      Ingo Molnar 提交于
      Steven Rostedt found a bug in where in his modified kernel
      ftrace was unable to modify the kernel text, due to the PMD
      itself having been marked read-only as well in
      split_large_page().
      
      The fix, suggested by Linus, is to not try to 'clone' the
      reference protection of a huge-page, but to use the standard
      (and permissive) page protection bits of KERNPG_TABLE.
      
      The 'cloning' makes sense for the ptes but it's a confused and
      incorrect concept at the page table level - because the
      pagetable entry is a set of all ptes and hence cannot
      'clone' any single protection attribute - the ptes can be any
      mixture of protections.
      
      With the permissive KERNPG_TABLE, even if the pte protections
      get changed after this point (due to ftrace doing code-patching
      or other similar activities like kprobes), the resulting combined
      protections will still be correct and the pte's restrictive
      (or permissive) protections will control it.
      
      Also update the comment.
      
      This bug was there for a long time but has not caused visible
      problems before as it needs a rather large read-only area to
      trigger. Steve possibly hacked his kernel with some really
      large arrays or so. Anyway, the bug is definitely worth fixing.
      
      [ Huang Ying also experienced problems in this area when writing
        the EFI code, but the real bug in split_large_page() was not
        realized back then. ]
      Reported-by: NSteven Rostedt <rostedt@goodmis.org>
      Reported-by: NHuang Ying <ying.huang@intel.com>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      07a66d7c