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    SubjectRe: [PATCH] memory mapped files not updating timestamps
    Peter Staubach a écrit :
    > --- linux-2.6.16.i686/mm/msync.c.org
    > +++ linux-2.6.16.i686/mm/msync.c
    > @@ -206,12 +206,16 @@ asmlinkage long sys_msync(unsigned long
    > file = vma->vm_file;
    > start = vma->vm_end;
    > if ((flags & MS_ASYNC) && file && nr_pages_dirtied) {
    > + struct address_space *mapping = file->f_mapping;
    > +
    > get_file(file);
    > up_read(&current->mm->mmap_sem);
    > - balance_dirty_pages_ratelimited_nr(file->f_mapping,
    > + balance_dirty_pages_ratelimited_nr(mapping,
    > nr_pages_dirtied);
    > fput(file);

    <here>, another thread can perform an munmap(), and the file can be totally
    dismantled.

    > down_read(&current->mm->mmap_sem);

    So referencing 'mapping' is *buggy* here.
    I believe that you have to move 'fput(file);' *after* the folloging two lines.

    > + if (test_and_clear_bit(AS_MCTIME, &mapping->flags))
    > + inode_update_time(mapping->host);
    > vma = find_vma(current->mm, start);
    > } else if ((flags & MS_SYNC) && file &&
    > (vma->vm_flags & VM_SHARED)) {


    Eric
    -
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