From: "Jakub Kiciński" <moorray3@wp•pl>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: netdev@vger•kernel.org, Fan Du <fan.du@windriver•com>,
Steffen Klassert <steffen.klassert@secunet•com>
Subject: Re: net-next: NULL pointer dereference on adding a net namespace and a system freeze
Date: Mon, 10 Mar 2014 13:19:09 +0100 [thread overview]
Message-ID: <20140310131909.33a3042c@north> (raw)
In-Reply-To: <1394424557.3607.4.camel@edumazet-glaptop2.roam.corp.google.com>
On Sun, 09 Mar 2014 21:09:17 -0700, Eric Dumazet wrote:
> On Sun, 2014-03-09 at 21:02 -0700, Eric Dumazet wrote:
> > On Mon, 2014-03-10 at 01:44 +0100, Jakub Kicinski wrote:
> > > Hi!
> > >
> > > Running Fedora 20 with net-next I get the following warning when
> > > libvirt or rtkit comes up:
> > >
> > > [ 272.143488] kmem_cache_sanity_check (flow_cache): Cache name already exists.
> > > [ 272.143586] CPU: 0 PID: 975 Comm: libvirtd Not tainted 3.14.0-rc5+ #1
> > > [ 272.143589] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
> > > [ 272.143591] 0000000000000000 ffff88003ceadba0 ffffffff8167baf0 ffff88003db3d300
> > > [ 272.143595] ffff88003ceadc18 ffffffff8117795b ffff88003ceadbc8 ffff88003b235158
> > > [ 272.143599] 0000000000000000 0000000000040000 0000000000000068 0000000000000000
> > > [ 272.143602] Call Trace:
> > > [ 272.143610] [<ffffffff8167baf0>] dump_stack+0x4d/0x66
> > > [ 272.143615] [<ffffffff8117795b>] kmem_cache_create_memcg+0x12b/0x420
> > > [ 272.143618] [<ffffffff81177c7b>] kmem_cache_create+0x2b/0x30
> > > [ 272.143622] [<ffffffff815c4a0e>] flow_cache_init+0x2e/0x2b0
> > > [ 272.143626] [<ffffffff8164b017>] xfrm_net_init+0x227/0x360
> > > [ 272.143629] [<ffffffff8164af41>] ? xfrm_net_init+0x151/0x360
> > > [ 272.143632] [<ffffffff815a5921>] ops_init+0x41/0x150
> > > [ 272.143635] [<ffffffff815a5aa3>] setup_net+0x73/0x110
> > > [ 272.143638] [<ffffffff815a5fe2>] copy_net_ns+0x72/0x100
> > > [ 272.143642] [<ffffffff810943f9>] create_new_namespaces+0xf9/0x190
> > > [ 272.143645] [<ffffffff81094560>] copy_namespaces+0xd0/0xf0
> > > [ 272.143648] [<ffffffff81094495>] ? copy_namespaces+0x5/0xf0
> > > [ 272.143651] [<ffffffff81069be0>] copy_process.part.31+0x950/0x1b30
> > > [ 272.143655] [<ffffffff8106af95>] do_fork+0xd5/0x370
> > > [ 272.143658] [<ffffffff811c1b2d>] ? __fput+0x17d/0x240
> > > [ 272.143662] [<ffffffff8110440c>] ? __audit_syscall_entry+0x9c/0xf0
> > > [ 272.143665] [<ffffffff8106b2b6>] SyS_clone+0x16/0x20
> > > [ 272.143669] [<ffffffff8168cf19>] stub_clone+0x69/0x90
> > > [ 272.143673] [<ffffffff8168cb69>] ? system_call_fastpath+0x16/0x1b
> > >
> > >
> > > When I try to add a netns with
> > > # ip netns add abcd
> > > I it dies with:
> >
> >
> > Yep, commit ca925cf1534ebcec332c08719a7dee6ee1782ce4 is buggy.
> >
> > flowcache: Make flow cache name space aware
> >
> > Inserting a entry into flowcache, or flushing flowcache should be based
> > on per net scope. The reason to do so is flushing operation from fat
> > netns crammed with flow entries will also making the slim netns with only
> > a few flow cache entries go away in original implementation.
> >
> > Since flowcache is tightly coupled with IPsec, so it would be easier to
> > put flow cache global parameters into xfrm namespace part. And one last
> > thing needs to do is bumping flow cache genid, and flush flow cache should
> > also be made in per net style.
> >
> > Signed-off-by: Fan Du <fan.du@windriver•com>
> > Signed-off-by: Steffen Klassert <steffen.klassert@secunet•com>
> >
> > I fail to understand why the kmem_cache must be private to a netns.
>
> Could you please try the following patch ?
It helps with the flow_cache warning and BUG ("ip netns add" works) but
machine still freezes after 5-10 minutes. I will try to revert
ca925cf1534ebcec332c08719a7dee6ee1782ce4 and see if that solves it.
-- kuba
> diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h
> index 51f0dce7b643..3492434baf88 100644
> --- a/include/net/netns/xfrm.h
> +++ b/include/net/netns/xfrm.h
> @@ -64,7 +64,6 @@ struct netns_xfrm {
>
> /* flow cache part */
> struct flow_cache flow_cache_global;
> - struct kmem_cache *flow_cachep;
> atomic_t flow_cache_genid;
> struct list_head flow_cache_gc_list;
> spinlock_t flow_cache_gc_lock;
> diff --git a/net/core/flow.c b/net/core/flow.c
> index 344a184011fd..102f8ea2eb6e 100644
> --- a/net/core/flow.c
> +++ b/net/core/flow.c
> @@ -45,6 +45,8 @@ struct flow_flush_info {
> struct completion completion;
> };
>
> +static struct kmem_cache *flow_cachep __read_mostly;
> +
> #define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
> #define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
>
> @@ -75,7 +77,7 @@ static void flow_entry_kill(struct flow_cache_entry *fle,
> {
> if (fle->object)
> fle->object->ops->delete(fle->object);
> - kmem_cache_free(xfrm->flow_cachep, fle);
> + kmem_cache_free(flow_cachep, fle);
> }
>
> static void flow_cache_gc_task(struct work_struct *work)
> @@ -230,7 +232,7 @@ flow_cache_lookup(struct net *net, const struct flowi *key, u16 family, u8 dir,
> if (fcp->hash_count > fc->high_watermark)
> flow_cache_shrink(fc, fcp);
>
> - fle = kmem_cache_alloc(net->xfrm.flow_cachep, GFP_ATOMIC);
> + fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
> if (fle) {
> fle->net = net;
> fle->family = family;
> @@ -435,10 +437,10 @@ int flow_cache_init(struct net *net)
> int i;
> struct flow_cache *fc = &net->xfrm.flow_cache_global;
>
> - /* Initialize per-net flow cache global variables here */
> - net->xfrm.flow_cachep = kmem_cache_create("flow_cache",
> - sizeof(struct flow_cache_entry),
> - 0, SLAB_PANIC, NULL);
> + if (!flow_cachep)
> + flow_cachep = kmem_cache_create("flow_cache",
> + sizeof(struct flow_cache_entry),
> + 0, SLAB_PANIC, NULL);
> spin_lock_init(&net->xfrm.flow_cache_gc_lock);
> INIT_LIST_HEAD(&net->xfrm.flow_cache_gc_list);
> INIT_WORK(&net->xfrm.flow_cache_gc_work, flow_cache_gc_task);
>
>
>
next prev parent reply other threads:[~2014-03-10 12:19 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-10 0:44 net-next: NULL pointer dereference on adding a net namespace and a system freeze Jakub Kicinski
2014-03-10 4:02 ` Eric Dumazet
2014-03-10 4:09 ` Eric Dumazet
2014-03-10 6:51 ` Fan Du
2014-03-10 13:44 ` Eric Dumazet
2014-03-10 14:09 ` [PATCH net-next] flowcache: restore a single flow_cache kmem_cache Eric Dumazet
2014-03-11 1:45 ` David Miller
2014-03-10 12:19 ` Jakub Kiciński [this message]
2014-03-10 14:04 ` net-next: NULL pointer dereference on adding a net namespace and a system freeze Eric Dumazet
2014-03-11 0:46 ` Jakub Kiciński
2014-03-11 5:30 ` Steffen Klassert
2014-03-11 12:00 ` Steffen Klassert
2014-03-11 12:40 ` Eric Dumazet
2014-03-11 13:20 ` Steffen Klassert
2014-03-11 14:30 ` Jakub Kiciński
2014-03-12 8:38 ` Steffen Klassert
2014-03-12 8:43 ` [PATCH net-next] flowcache: Fix resource leaks on namespace exit Steffen Klassert
2014-03-12 11:43 ` Eric Dumazet
2014-03-12 19:31 ` David Miller
2014-03-11 12:42 ` net-next: NULL pointer dereference on adding a net namespace and a system freeze Jakub Kiciński
2014-03-12 10:02 ` Fan Du
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