From: Heiner Kallweit <hkallweit1@gmail.com>
To: Ido Schimmel <idosch@idosch.org>, Eric Dumazet <eric.dumazet@gmail.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: ipv6_addrconf: WARNING about suspicious RCU usage
Date: Sat, 20 Jan 2018 20:48:49 +0100 [thread overview]
Message-ID: <0aa8167b-d2fd-8631-d30f-928c20640444@gmail.com> (raw)
In-Reply-To: <20180120191959.GA5010@splinter>
Am 20.01.2018 um 20:19 schrieb Ido Schimmel:
> On Sat, Jan 20, 2018 at 10:49:03AM -0800, Eric Dumazet wrote:
>> On Sat, 2018-01-20 at 15:37 +0200, Ido Schimmel wrote:
>>> On Sat, Jan 20, 2018 at 12:57:01PM +0100, Heiner Kallweit wrote:
>>>> Since some time (didn't bisect it yet) I get the following warning.
>>>> Is it a known issue?
>>>
>>> [...]
>>>
>>>> [86220.126999] BUG: sleeping function called from invalid context at mm/slab.h:420
>>>> [86220.127041] in_atomic(): 1, irqs_disabled(): 0, pid: 1003, name: kworker/0:2
>>>> [86220.127082] 4 locks held by kworker/0:2/1003:
>>>> [86220.127107] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
>>>> [86220.127179] #1: ((addr_chk_work).work){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
>>>> [86220.127242] #2: (rtnl_mutex){+.+.}, at: [<00000000b06d9510>] rtnl_lock+0x12/0x20
>>>> [86220.127300] #3: (rcu_read_lock_bh){....}, at: [<00000000aef52299>] addrconf_verify_rtnl+0x1e/0x510 [ipv6]
>>>> [86220.127414] CPU: 0 PID: 1003 Comm: kworker/0:2 Not tainted 4.15.0-rc7-next-20180110+ #7
>>>> [86220.127463] Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015
>>>> [86220.127528] Workqueue: ipv6_addrconf addrconf_verify_work [ipv6]
>>>> [86220.127568] Call Trace:
>>>> [86220.127591] dump_stack+0x70/0x9e
>>>> [86220.127616] ___might_sleep+0x14d/0x240
>>>> [86220.127644] __might_sleep+0x45/0x80
>>>> [86220.127672] kmem_cache_alloc_trace+0x53/0x250
>>>> [86220.127717] ? ipv6_add_addr+0xfe/0x6e0 [ipv6]
>>>> [86220.127762] ipv6_add_addr+0xfe/0x6e0 [ipv6]
>>>> [86220.127807] ipv6_create_tempaddr+0x24d/0x430 [ipv6]
>>>> [86220.127854] ? ipv6_create_tempaddr+0x24d/0x430 [ipv6]
>>>> [86220.127903] addrconf_verify_rtnl+0x339/0x510 [ipv6]
>>>> [86220.127950] ? addrconf_verify_rtnl+0x339/0x510 [ipv6]
>>>> [86220.127998] addrconf_verify_work+0xe/0x20 [ipv6]
>>>> [86220.128032] process_one_work+0x258/0x680
>>>> [86220.128063] worker_thread+0x35/0x3f0
>>>> [86220.128091] kthread+0x124/0x140
>>>> [86220.128117] ? process_one_work+0x680/0x680
>>>> [86220.128146] ? kthread_create_worker_on_cpu+0x40/0x40
>>>> [86220.128180] ? umh_complete+0x40/0x40
>>>> [86220.128207] ? call_usermodehelper_exec_async+0x12a/0x160
>>>> [86220.128243] ret_from_fork+0x4b/0x60
>>>
>>> Can you please try attached patch (untested)?
>>
>>
>>
>> I would also/instead break rcu section.
>
> Thanks Eric, this should work. We can continue to block in
> ipv6_create_tempaddr().
>
> Heiner, can you try Eric's patch instead?
>
Sure, thanks for the quick response to both of you.
>>
>> Holding RCU (and BH) for whole hash traversal is a recipe for disaster,
>> if we have thousands of IPv6 addresses.
>>
>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>> index ab99cb641b7cccdda0ad4ae553c09274d7dbc047..adda73466ae1dd0f3b700b3db5fbf3065e4d3f7f 100644
>> --- a/net/ipv6/addrconf.c
>> +++ b/net/ipv6/addrconf.c
>> @@ -4356,9 +4356,11 @@ static void addrconf_verify_rtnl(void)
>> spin_lock(&ifpub->lock);
>> ifpub->regen_count = 0;
>> spin_unlock(&ifpub->lock);
>> + rcu_read_unlock_bh();
>> ipv6_create_tempaddr(ifpub, ifp, true);
>> in6_ifa_put(ifpub);
>> in6_ifa_put(ifp);
>> + rcu_read_lock_bh();
>> goto restart;
>> }
>> } else if (time_before(ifp->tstamp + ifp->prefered_lft * HZ - regen_advance * HZ, next))
>>
>>
>>
>>
>
next prev parent reply other threads:[~2018-01-20 19:48 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-20 11:57 ipv6_addrconf: WARNING about suspicious RCU usage Heiner Kallweit
2018-01-20 13:37 ` Ido Schimmel
2018-01-20 18:49 ` Eric Dumazet
2018-01-20 19:19 ` Ido Schimmel
2018-01-20 19:48 ` Heiner Kallweit [this message]
2018-01-21 21:22 ` Heiner Kallweit
2018-01-23 18:01 ` Ido Schimmel
2018-01-23 18:43 ` Eric Dumazet
2018-01-27 0:10 ` [PATCH net] ipv6: addrconf: break critical section in addrconf_verify_rtnl() Eric Dumazet
2018-01-27 8:52 ` Ido Schimmel
2018-01-29 19:24 ` David Miller
2018-01-26 22:15 ` ipv6_addrconf: WARNING about suspicious RCU usage Heiner Kallweit
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