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    SubjectRe: {painfully BISECTED} Please revert f25c80a4b2: arch/um/drivers: remove duplicate structure field initialization
    On Tue, 28 Sep 2010 13:24:40 -0700
    Linus Torvalds <> wrote:

    > Ping, no comments?
    > On Mon, Sep 27, 2010 at 6:17 AM, Boaz Harrosh <> wrote:
    > >
    > > [bharrosh@fs2 ~/dev/git/pub/scsi-misc] 1115$ git bisect good
    > > f25c80a4b2bf93c99820f470573626557db35202 is the first bad commit
    > > commit f25c80a4b2bf93c99820f470573626557db35202
    > It looks like that commit is indeed very misleading. The commit message says:
    > "arch/um/drivers: remove duplicate structure field initialization"
    > but it is in fact not duplicate: there's two field initializations,
    > but they are _different_. Looking at the patch, it has:
    > .ndo_set_mac_address = uml_net_set_mac,
    > - .ndo_set_mac_address = eth_mac_addr,
    > so it removes the later one, but it is not at all clear which one the
    > compiler actually used. My guess is that it used to use the later one
    > (the standard eth_mac_addr function), and the patch made it suddenly
    > use the uml_net_set_mac function.
    > I didn't check what gcc used to do, but this:
    > > The patch Reverts cleanly on top of 2.6.36-rc5 and after Revert works perfectly as
    > > before.
    > makes me suspect that nobody else checked it either.

    I checked! gcc uses the second initialiser.

    uml_net_set_mac() is:

    static int uml_net_set_mac(struct net_device *dev, void *addr)
    struct uml_net_private *lp = netdev_priv(dev);
    struct sockaddr *hwaddr = addr;

    eth_mac_addr(dev, hwaddr->sa_data);

    return 0;

    And I misread that, assuming that it's just a wrapper around
    eth_mac_addr(). Only it isn't, because it passes eth_mac_addr() the
    MAC address's address directly (with ->sa_data). But eth_mac_addr()
    expects a `struct sockaddr *'.

    And for some wtf reason, eth_mac_addr() passes that `struct
    sockaddr *' in a `void *', thus cunningly hiding the bug.

    Yeah, please revert it.

     \ /
      Last update: 2010-09-28 22:51    [W:0.023 / U:18.880 seconds]
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