Commit:     5307cc1aa53850f017c8053db034cf950b670ac9
Parent:     bb374b7b938f73666c403b201b3dd48ec9fe118a
Author:     Linus Torvalds <[EMAIL PROTECTED]>
AuthorDate: Wed Oct 31 09:19:46 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Oct 31 09:19:46 2007 -0700

    Remove broken ptrace() special-case code from file mapping
    The kernel has for random historical reasons allowed ptrace() accesses
    to access (and insert) pages into the page cache above the size of the
    However, Nick broke that by mistake when doing the new fault handling in
    commit 54cb8821de07f2ffcd28c380ce9b93d5784b40d7 ("mm: merge populate and
    nopage into fault (fixes nonlinear)".  The breakage caused a hang with
    gdb when trying to access the invalid page.
    The ptrace "feature" really isn't worth resurrecting, since it really is
    wrong both from a portability _and_ from an internal page cache validity
    standpoint.  So this removes those old broken remnants, and fixes the
    ptrace() hang in the process.
    Noticed and bisected by Duane Griffin, who also supplied a test-case
    (quoth Nick: "Well that's probably the best bug report I've ever had,
    thanks Duane!").
    Cc: Duane Griffin <[EMAIL PROTECTED]>
    Acked-by: Nick Piggin <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 mm/filemap.c |   13 ++-----------
 1 files changed, 2 insertions(+), 11 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 9940895..188cf5f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1300,7 +1300,7 @@ int filemap_fault(struct vm_area_struct *vma, struct 
vm_fault *vmf)
        size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
        if (vmf->pgoff >= size)
-               goto outside_data_content;
+               return VM_FAULT_SIGBUS;
        /* If we don't want any read-ahead, don't bother */
        if (VM_RandomReadHint(vma))
@@ -1377,7 +1377,7 @@ retry_find:
        if (unlikely(vmf->pgoff >= size)) {
-               goto outside_data_content;
+               return VM_FAULT_SIGBUS;
@@ -1388,15 +1388,6 @@ retry_find:
        vmf->page = page;
        return ret | VM_FAULT_LOCKED;
-       /*
-        * An external ptracer can access pages that normally aren't
-        * accessible..
-        */
-       if (vma->vm_mm == current->mm)
-               return VM_FAULT_SIGBUS;
-       /* Fall through to the non-read-ahead case */
         * We're only likely to ever get here if MADV_RANDOM is in
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