Messages in this thread | | | From | Eric Dumazet <> | Date | Tue, 20 Apr 2021 10:34:17 +0200 | Subject | Re: [PATCH] net: called rtnl_unlock() before runpm resumes devices |
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On Tue, Apr 20, 2021 at 9:54 AM AceLan Kao <acelan.kao@canonical.com> wrote: > > From: "Chia-Lin Kao (AceLan)" <acelan.kao@canonical.com> > > The rtnl_lock() has been called in rtnetlink_rcv_msg(), and then in > __dev_open() it calls pm_runtime_resume() to resume devices, and in > some devices' resume function(igb_resum,igc_resume) they calls rtnl_lock() > again. That leads to a recursive lock. > > It should leave the devices' resume function to decide if they need to > call rtnl_lock()/rtnl_unlock(), so call rtnl_unlock() before calling > pm_runtime_resume() and then call rtnl_lock() after it in __dev_open(). > >
Hi Acelan
When was the bugg added ? Please add a Fixes: tag
By doing so, you give more chances for reviewers to understand why the fix is not risky, and help stable teams work.
Thanks.
> Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com> > --- > net/core/dev.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/net/core/dev.c b/net/core/dev.c > index 1f79b9aa9a3f..427cbc80d1e5 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -1537,8 +1537,11 @@ static int __dev_open(struct net_device *dev, struct netlink_ext_ack *extack) > > if (!netif_device_present(dev)) { > /* may be detached because parent is runtime-suspended */ > - if (dev->dev.parent) > + if (dev->dev.parent) { > + rtnl_unlock(); > pm_runtime_resume(dev->dev.parent); > + rtnl_lock(); > + } > if (!netif_device_present(dev)) > return -ENODEV; > } > -- > 2.25.1 >
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