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    SubjectRe: [UPDATED PATCH] fix memory corruption from misinterpreted bad_inode_ops return values
    On Thu, 04 Jan 2007 12:33:59 -0600
    Eric Sandeen <sandeen@redhat.com> wrote:

    > Andrew Morton wrote:
    > > On Thu, 04 Jan 2007 11:51:10 -0600
    > > Eric Sandeen <sandeen@redhat.com> wrote:
    >
    > >> Also - is it ok to alias a function with one signature to a function with
    > >> another signature?
    > >
    > > Ordinarily I'd say no wucking fay, but that's effectively what we've been
    > > doing in there for ages, and it seems to work.
    >
    > Hmm that gives me a lot of confidence ;-) I'd hate to carry along bad
    > assumptions while we try to make this all kosher... but I'm willing to
    > defer to popular opinion on this one....

    yeah, I'm a bit wobbly about it. Linus, what do you think?

    > > I'd be a bit worried if any of these functions were returning pointers,
    > > because one could certainly conceive of an arch+compiler combo which
    > > returns pointers in a different register from integers (680x0?) but that's
    > > not happening here.
    >
    > Well, one is...
    >
    > static long * return_EIO_ptr(void)
    > {
    > return ERR_PTR(-EIO);
    > }
    > ...
    > static struct dentry *bad_inode_lookup(struct inode * dir,
    > struct dentry *dentry, struct nameidata *nd)
    > __attribute__((alias("return_EIO_ptr")));
    >
    > Maybe it'd be better to lose the alias in this case then? and go back
    > to this:
    >
    > static struct dentry *bad_inode_lookup(struct inode * dir,
    > struct dentry *dentry, struct nameidata *nd)
    > {
    > return ERR_PTR(-EIO);
    > }

    A bit saner, but again, the old code used the same function for *everything*
    and apart from the 32/64-bit thing, it worked.

    Half a kb isn't much of course, but we've done lots of changes for a lot
    less...


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