From: Eric Dumazet <eric.dumazet@gmail.com>
To: Ido Schimmel <idosch@idosch.org>,
Heiner Kallweit <hkallweit1@gmail.com>,
David Miller <davem@davemloft.net>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: [PATCH net] ipv6: addrconf: break critical section in addrconf_verify_rtnl()
Date: Fri, 26 Jan 2018 16:10:43 -0800 [thread overview]
Message-ID: <1517011843.3715.68.camel@gmail.com> (raw)
In-Reply-To: <1516732983.3715.6.camel@gmail.com>
From: Eric Dumazet <edumazet@google.com>
Heiner reported a lockdep splat [1]
This is caused by attempting GFP_KERNEL allocation while RCU lock is
held and BH blocked.
We believe that addrconf_verify_rtnl() could run for a long period,
so instead of using GFP_ATOMIC here as Ido suggested, we should break
the critical section and restart it after the allocation.
[1]
[86220.125562] =============================
[86220.125586] WARNING: suspicious RCU usage
[86220.125612] 4.15.0-rc7-next-20180110+ #7 Not tainted
[86220.125641] -----------------------------
[86220.125666] kernel/sched/core.c:6026 Illegal context switch in RCU-bh read-side critical section!
[86220.125711]
other info that might help us debug this:
[86220.125755]
rcu_scheduler_active = 2, debug_locks = 1
[86220.125792] 4 locks held by kworker/0:2/1003:
[86220.125817] #0: ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.125895] #1: ((addr_chk_work).work){+.+.}, at: [<00000000da8e9b73>] process_one_work+0x1de/0x680
[86220.125959] #2: (rtnl_mutex){+.+.}, at: [<00000000b06d9510>] rtnl_lock+0x12/0x20
[86220.126017] #3: (rcu_read_lock_bh){....}, at: [<00000000aef52299>] addrconf_verify_rtnl+0x1e/0x510 [ipv6]
[86220.126111]
stack backtrace:
[86220.126142] CPU: 0 PID: 1003 Comm: kworker/0:2 Not tainted 4.15.0-rc7-next-20180110+ #7
[86220.126185] Hardware name: ZOTAC ZBOX-CI321NANO/ZBOX-CI321NANO, BIOS B246P105 06/01/2015
[86220.126250] Workqueue: ipv6_addrconf addrconf_verify_work [ipv6]
[86220.126288] Call Trace:
[86220.126312] dump_stack+0x70/0x9e
[86220.126337] lockdep_rcu_suspicious+0xce/0xf0
[86220.126365] ___might_sleep+0x1d3/0x240
[86220.126390] __might_sleep+0x45/0x80
[86220.126416] kmem_cache_alloc_trace+0x53/0x250
[86220.126458] ? ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.126498] ipv6_add_addr+0xfe/0x6e0 [ipv6]
[86220.126538] ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.126580] ? ipv6_create_tempaddr+0x24d/0x430 [ipv6]
[86220.126623] addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.126664] ? addrconf_verify_rtnl+0x339/0x510 [ipv6]
[86220.126708] addrconf_verify_work+0xe/0x20 [ipv6]
[86220.126738] process_one_work+0x258/0x680
[86220.126765] worker_thread+0x35/0x3f0
[86220.126790] kthread+0x124/0x140
[86220.126813] ? process_one_work+0x680/0x680
[86220.126839] ? kthread_create_worker_on_cpu+0x40/0x40
[86220.126869] ? umh_complete+0x40/0x40
[86220.126893] ? call_usermodehelper_exec_async+0x12a/0x160
[86220.126926] ret_from_fork+0x4b/0x60
[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
Fixes: f3d9832e56c4 ("ipv6: addrconf: cleanup locking in ipv6_add_addr")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Heiner Kallweit <hkallweit1@gmail.com>
---
net/ipv6/addrconf.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f49bd7897e95f15a381e4700660991f2d3c3fed4..10facd174210974ac82b2304211061b90714aac8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4352,9 +4352,11 @@ 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:[~2018-01-27 0:10 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
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 ` Eric Dumazet [this message]
2018-01-27 8:52 ` [PATCH net] ipv6: addrconf: break critical section in addrconf_verify_rtnl() Ido Schimmel
2018-01-29 19:24 ` David Miller
2018-01-26 22:15 ` ipv6_addrconf: WARNING about suspicious RCU usage Heiner Kallweit
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1517011843.3715.68.camel@gmail.com \
--to=eric.dumazet@gmail.com \
--cc=davem@davemloft.net \
--cc=hkallweit1@gmail.com \
--cc=idosch@idosch.org \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.