Re: [PATCH 2/4] staging: vme: make match() driver specific toimprove non-VME64x support

From: Emilio G. Cota
Date: Mon Sep 26 2011 - 19:29:28 EST


On Mon, Sep 26, 2011 at 11:27:16 +0200, Manohar Vanga wrote:
(snip)
> diff --git a/drivers/staging/vme/vme.c b/drivers/staging/vme/vme.c
> index 76e08f3..9cb6938 100644
> --- a/drivers/staging/vme/vme.c
> +++ b/drivers/staging/vme/vme.c
> @@ -1317,6 +1317,7 @@ static int vme_add_bus(struct vme_bridge *bridge)
> if ((vme_bus_numbers & (1 << i)) == 0) {
> vme_bus_numbers |= (1 << i);
> bridge->num = i;
> + INIT_LIST_HEAD(&bridge->devices);
> list_add_tail(&bridge->bus_list, &vme_bus_list);

Just realised that vme_buses_lock also protects vme_bus_list; appending
to this list here should be protected by the mutex, otherwise
vme_add_bus (ie this function) could race with __vme_register_driver,
which might access a corrupt copy of the list.

Note that vme_remove_bus does the right thing though; it acquires
the lock before unpinning the bridge from vme_bus_list.

Emilio

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