search for: prepage_pages

...to pwrite to write to the same page of the same file. In btrfs_file_aio_write(), the pages is locked by prepare_pages(). So when btrfs_copy_from_user() is called, page fault happens and the same page needs to be locked again in filemap_fault(). The fix is to move iov_iter_fault_in_readable() before prepage_pages() to make page fault happen before pages are locked. And also disable page fault in critical region in btrfs_copy_from_user(). Signed-off-by: Xin Zhong <xin.zhong@intel.com> --- fs/btrfs/file.c | 23 +++++------------------ 1 files changed, 5 insertions(+), 18 deletions(-) diff --git a/f...

(switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Thu, 6 Jan 2011 20:59:08 GMT bugzilla-daemon@bugzilla.kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=26242 > > Summary: BUG: unable to handle kernel NULL pointer dereference > at (null) > Product: Memory Management >