Messages in this thread Patch in this message | | | Date | Wed, 23 Sep 2015 22:46:00 +0200 | Subject | Re: [Linux 4.2-rc8+...v4.3-rc2] REGRESSION: ppp: circular locking dependency detected: [pppd] ppp_dev_uninit() | rtnl_lock() | From | Sedat Dilek <> |
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On Wed, Sep 23, 2015 at 12:38 PM, Guillaume Nault <g.nault@alphalink.fr> wrote: > On Wed, Sep 23, 2015 at 08:06:16AM +0200, Sedat Dilek wrote: >> Without reverting the below culprit ppp patch... >> >> commit/?id=8cb775bc0a34dc596837e7da03fd22c747be618b >> ("ppp: fix device unregistration upon netns deletion") >> >> ...I have an unstable Internet connection via Network-Manager/ModemManager. >> >> First I saw this with Linux v4.2. >> > > Thanks for reporting the issue. Can you test this patch ? > > --- > diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c > index 0481daf..ed00446 100644 > --- a/drivers/net/ppp/ppp_generic.c > +++ b/drivers/net/ppp/ppp_generic.c > @@ -2755,6 +2755,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, > */ > dev_net_set(dev, net); > > + rtnl_lock(); > mutex_lock(&pn->all_ppp_mutex); > > if (unit < 0) { > @@ -2785,7 +2786,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, > ppp->file.index = unit; > sprintf(dev->name, "ppp%d", unit); > > - ret = register_netdev(dev); > + ret = register_netdevice(dev); > if (ret != 0) { > unit_put(&pn->units_idr, unit); > netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n", > @@ -2797,6 +2798,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, > > atomic_inc(&ppp_unit_count); > mutex_unlock(&pn->all_ppp_mutex); > + rtnl_unlock(); > > *retp = 0; > return ppp;
I have adapted your patch against Linux v4.2.1 and it fixes the issue for me. Testcase: 1. Stop network-manager and unload "PPP Deflate Compression module". 2. Reload module and restart NM. ( No call-traces pointing to ppp. )
Do you mind to send a proper patch with subject-line and commit-message? Can you embed the Fixes-tag and give credits like Reported-by/Tested-by?
Thanks.
- Sedat - From d4ace3e00129687b680977ecc5ea4c9a03e35b63 Mon Sep 17 00:00:00 2001 From: Sedat Dilek <sedat.dilek@gmail.com> Date: Wed, 23 Sep 2015 22:33:31 +0200 Subject: [PATCH] ppp: Fix circular locking dependency
--- drivers/net/ppp/ppp_generic.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index fa8f5046afe9..487be20b6b12 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -2742,6 +2742,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, */ dev_net_set(dev, net); + rtnl_lock(); mutex_lock(&pn->all_ppp_mutex); if (unit < 0) { @@ -2772,7 +2773,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, ppp->file.index = unit; sprintf(dev->name, "ppp%d", unit); - ret = register_netdev(dev); + ret = register_netdevice(dev); if (ret != 0) { unit_put(&pn->units_idr, unit); netdev_err(ppp->dev, "PPP: couldn't register device %s (%d)\n", @@ -2784,6 +2785,7 @@ static struct ppp *ppp_create_interface(struct net *net, int unit, atomic_inc(&ppp_unit_count); mutex_unlock(&pn->all_ppp_mutex); + rtnl_unlock(); *retp = 0; return ppp; -- 2.5.3
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