Re: xfs: Uninitialized memory read at xlog_write

[Dave Chinner <david@fromorbit.com>]

On Mon, Sep 18, 2017 at 11:21:21AM -0700, Darrick J. Wong wrote:
> On Fri, Sep 15, 2017 at 08:44:31AM +1000, Dave Chinner wrote:
> > xfs: Don't log uninitialised fields in inode structures
> > 
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > Prevent kmemcheck from throwing warnings about reading uninitialised
> > memory when formatting inodes into the incore log buffer. There are
> > several issues here - we don't always log all the fields in the
> > inode log format item, and we never log the inode the
> > di_next_unlinked field.
> > 
> > In the case of the inode log format item, this is aused b cerbated
> 
> "is aused b cerbated" ?

vi fail when replacing the word "used" with "exacerbated". :)

> > by the old xfs_inode_log_format structure padding issue. Hence make
> > the padded, 64 bit aligned version of the structure the one we always
> > use for formatting the log and get rid of the 64 bit variant. This
> > means we'll always log the 64-bit version and so recovery only needs
> > to convert from the unpadded 32 bit version from older 32 bit
> > kernels.
> 
> And those old 32-bit kernels can read the xfs_inode_log_format{,_64}
> structures, right?

Yes. With the in-memory format now being the same as the old
xfs_inode_log_format_64 structure in the log, we only need a
conversion from "32 bit in log to 64 bit in memory" on all
platforms.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com