Messages in this thread |  | | Date | Sun, 19 Jan 2025 13:45:18 +0100 | | From | Kory Maincent <> | | Subject | Re: [PATCH net-next v2] net: phy: Fix suspicious rcu_dereference usage |
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On Fri, 17 Jan 2025 19:07:20 -0800 Jakub Kicinski <kuba@kernel.org> wrote:
> On Fri, 17 Jan 2025 23:16:59 +0100 Kory Maincent wrote: > > > If not protected by RTNL, what prevents two threads from calling this > > > function at the same time, > > > thus attempting to kfree_rcu() the same pointer twice ? > > > > I don't think this function can be called simultaneously from two threads, > > if this were the case we would have already seen several issues with the > > phydev pointer. But maybe I am wrong. > > > > The rcu_lock here is to prevent concurrent dev->hwprov pointer modification > > done under rtnl_lock in net/ethtool/tsconfig.c. > > I could also be wrong, but I don't recall being told that suspend path > can't race with anything else. So I think ravb should probably take > rtnl_lock or some such when its shutting itself down.. ?
Should we add an ASSERT_RTNL call in the phy_detach function? (Maybe also in phy_attach to be consistent) Even thought, I think it may raise lots of warning from other NIT drivers.
> If I'm wrong I think we should mention this is from suspend and > add Claudiu's stack trace to the commit msg.
Ack.
Regards, -- Köry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com
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