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    SubjectRe: [PATCH v3 3/6] floppy: avoid leaking extra reference to queue on do_floppy_init error handling
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    On Tue, 2012-08-14 at 11:03 +0200, Stanislaw Gruszka wrote:
    > On Tue, Aug 14, 2012 at 04:20:39AM +0100, Ben Hutchings wrote:
    > > On Mon, 2012-08-13 at 15:16 -0300, Herton Ronaldo Krzesinski wrote:
    > > > After commit 3f9a5aa ("floppy: Cleanup disk->queue before caling
    > > > put_disk() if add_disk() was never called"), if something fails in the
    > > > add_disk loop, we unconditionally set disks[dr]->queue to NULL. But
    > > > that's wrong, since we may have succesfully done an add_disk on some of
    > > > the drives previously in the loop, and in this case we would end up with
    > > > an extra reference to the disks[dr]->queue.
    > > >
    > > > Add a new global array to mark "registered" disks, and use that to check
    > > > if we did an add_disk on one of the disks already. Using an array to
    > > > track added disks also will help to simplify/cleanup code later, as
    > > > suggested by Vivek Goyal.
    > > [...]
    > >
    > > It's totally ridiculous that a driver should have to do this. Any
    > > registered disk should have the GENHD_FL_UP flag set... so why can't
    > > genhd check it? It doesn't look like floppy is the only driver affected
    > > by this problem, either. So I suggest the following general fix
    > > (untested):
    > >
    > > ---
    > > Subject: genhd: Make put_disk() safe for disks that have not been registered
    > >
    > > Since commit 9f53d2f ('block: fix __blkdev_get and add_disk race
    > > condition'), add_disk() adds a reference to disk->queue,
    >
    > I do not see this? Commit 9f53d2fe insert disk_alloc_events() to add_disk(),
    > but disk_alloc_events() function does not get any reference to disk->queue,
    > I missed something?

    Sorry, not sure why I pointed to that one. The reference should of
    course be to:

    commit 523e1d399ce0e23bec562abe2b2f8d297af81161
    Author: Tejun Heo <tj@kernel.org>
    Date: Wed Oct 19 14:31:07 2011 +0200

    block: make gendisk hold a reference to its queue

    Ben.

    --
    Ben Hutchings
    I say we take off; nuke the site from orbit. It's the only way to be sure.
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