* next-20131218 - WARNING in qdisc_list_add
@ 2013-12-19 18:14 Valdis Kletnieks
2013-12-20 16:26 ` Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Valdis Kletnieks @ 2013-12-19 18:14 UTC (permalink / raw)
To: Eric Dumazet, netdev; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 3669 bytes --]
Seen once while booting next-20131218 (different boot than the BUG
I hit). Command that triggered it would have been one of these 2:
/usr/sbin/tc qdisc add dev em1 root codel
/usr/sbin/tc qdisc add dev wlp3s0 root codel
It's possible that wlp3s0 wasn't there yet due to rfkill switch having
nuked the wireless.
'git blame' points at the message being added in this commit:
commit e57a784d8cae429f5b697fe55abf420181d9ff09
Author: Eric Dumazet <edumazet@google.com>
Date: Thu Dec 12 15:41:56 2013 -0800
pkt_sched: set root qdisc before change() in attach_default_qdiscs()
After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave
qdiscs") we call disc_list_add() while the device qdisc might be
the noop_qdisc one.
This shows up as duplicates in "tc qdisc show", as all inactive devices
point to noop_qdisc.
Fix this by setting dev->qdisc to the new qdisc before calling
ops->change() in attach_default_qdiscs()
Add a WARN_ON_ONCE() to catch any future similar problem.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[ 153.876539] ------------[ cut here ]------------
[ 153.878667] WARNING: CPU: 1 PID: 1446 at net/sched/sch_api.c:278 qdisc_list_add+0x79/0xcf()
[ 153.897042] CPU: 3 PID: 1446 Comm: tc Tainted: G O 3.13.0-rc4-next-20131218 #129
[ 153.898877] Hardware name: Dell Inc. Latitude E6530/07Y85M, BIOS A11 03/12/2013
[ 153.900666] 0000000000000000 ffff880121195950 ffffffff8164c74f 0000000000000000
[ 153.905666] ffff880121195988 ffffffff8103875e ffffffff814afe73 ffff88012828f600
[ 153.910847] 0000000000000001 ffffffff81c8cac0 0000000000000001 ffff880121195998
[ 153.916012] Call Trace:
[ 153.917237] [<ffffffff8164c74f>] dump_stack+0x4f/0xa2
[ 153.918659] [<ffffffff8103875e>] warn_slowpath_common+0x7a/0x93
[ 153.920222] [<ffffffff814afe73>] ? qdisc_list_add+0x79/0xcf
[ 153.921896] [<ffffffff81038816>] warn_slowpath_null+0x15/0x17
[ 153.923579] [<ffffffff814afe73>] qdisc_list_add+0x79/0xcf
[ 153.925134] [<ffffffff814b1466>] qdisc_create+0x237/0x350
[ 153.926658] [<ffffffff814b1a05>] tc_modify_qdisc+0x486/0x4af
[ 153.928173] [<ffffffff814a2bb0>] rtnetlink_rcv_msg+0x180/0x193
[ 153.929753] [<ffffffff810c7c32>] ? trace_preempt_on+0x12/0x2f
[ 153.931453] [<ffffffff814a2a30>] ? rtnl_newlink+0x4ba/0x4ba
[ 153.933107] [<ffffffff814b67e4>] netlink_rcv_skb+0x44/0x86
[ 153.934586] [<ffffffff8149fbeb>] rtnetlink_rcv+0x1e/0x25
[ 153.936133] [<ffffffff814b62ef>] netlink_unicast+0xf1/0x175
[ 153.937587] [<ffffffff814b6677>] netlink_sendmsg+0x304/0x34e
[ 153.939088] [<ffffffff814794ac>] __sock_sendmsg_nosec+0x25/0x27
[ 153.940638] [<ffffffff8147b0c2>] sock_sendmsg+0x52/0x6c
[ 153.942278] [<ffffffff811009ce>] ? might_fault+0x9b/0x9f
[ 153.943980] [<ffffffff81100985>] ? might_fault+0x52/0x9f
[ 153.945439] [<ffffffff81487cec>] ? verify_iovec+0x5e/0xac
[ 153.946993] [<ffffffff8147cd41>] ___sys_sendmsg+0x20d/0x29d
[ 153.948540] [<ffffffff81073236>] ? arch_local_irq_save+0x9/0xc
[ 153.950087] [<ffffffff81072708>] ? up_read+0x22/0x25
[ 153.951743] [<ffffffff8165a21b>] ? __do_page_fault+0x56f/0x600
[ 153.953495] [<ffffffff810c7bdd>] ? time_hardirqs_on+0x1b/0x2f
[ 153.955175] [<ffffffff8113fdee>] ? fcheck_files+0x80/0xe0
[ 153.956720] [<ffffffff8114062d>] ? fget_light+0x30/0x90
[ 153.958195] [<ffffffff8147d20a>] __sys_sendmsg+0x3d/0x5b
[ 153.959645] [<ffffffff8147d235>] SyS_sendmsg+0xd/0x17
[ 153.961092] [<ffffffff8165d722>] system_call_fastpath+0x16/0x1b
[ 153.965229] ---[ end trace ec29ec2eecd5a461 ]---
[-- Attachment #2: Type: application/pgp-signature, Size: 865 bytes --]
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: next-20131218 - WARNING in qdisc_list_add
2013-12-19 18:14 next-20131218 - WARNING in qdisc_list_add Valdis Kletnieks
@ 2013-12-20 16:26 ` Eric Dumazet
2014-03-08 16:01 ` [PATCH net] pkt_sched: move the sanity test in qdisc_list_add() Eric Dumazet
0 siblings, 1 reply; 4+ messages in thread
From: Eric Dumazet @ 2013-12-20 16:26 UTC (permalink / raw)
To: Valdis Kletnieks; +Cc: Eric Dumazet, netdev, linux-kernel
On Thu, 2013-12-19 at 13:14 -0500, Valdis Kletnieks wrote:
> Seen once while booting next-20131218 (different boot than the BUG
> I hit). Command that triggered it would have been one of these 2:
>
> /usr/sbin/tc qdisc add dev em1 root codel
> /usr/sbin/tc qdisc add dev wlp3s0 root codel
>
> It's possible that wlp3s0 wasn't there yet due to rfkill switch having
> nuked the wireless.
>
> 'git blame' points at the message being added in this commit:
>
> commit e57a784d8cae429f5b697fe55abf420181d9ff09
> Author: Eric Dumazet <edumazet@google.com>
> Date: Thu Dec 12 15:41:56 2013 -0800
>
> pkt_sched: set root qdisc before change() in attach_default_qdiscs()
>
> After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave
> qdiscs") we call disc_list_add() while the device qdisc might be
> the noop_qdisc one.
>
> This shows up as duplicates in "tc qdisc show", as all inactive devices
> point to noop_qdisc.
>
> Fix this by setting dev->qdisc to the new qdisc before calling
> ops->change() in attach_default_qdiscs()
>
> Add a WARN_ON_ONCE() to catch any future similar problem.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
>
>
> [ 153.876539] ------------[ cut here ]------------
> [ 153.878667] WARNING: CPU: 1 PID: 1446 at net/sched/sch_api.c:278 qdisc_list_add+0x79/0xcf()
> [ 153.897042] CPU: 3 PID: 1446 Comm: tc Tainted: G O 3.13.0-rc4-next-20131218 #129
> [ 153.898877] Hardware name: Dell Inc. Latitude E6530/07Y85M, BIOS A11 03/12/2013
> [ 153.900666] 0000000000000000 ffff880121195950 ffffffff8164c74f 0000000000000000
> [ 153.905666] ffff880121195988 ffffffff8103875e ffffffff814afe73 ffff88012828f600
> [ 153.910847] 0000000000000001 ffffffff81c8cac0 0000000000000001 ffff880121195998
> [ 153.916012] Call Trace:
> [ 153.917237] [<ffffffff8164c74f>] dump_stack+0x4f/0xa2
> [ 153.918659] [<ffffffff8103875e>] warn_slowpath_common+0x7a/0x93
> [ 153.920222] [<ffffffff814afe73>] ? qdisc_list_add+0x79/0xcf
> [ 153.921896] [<ffffffff81038816>] warn_slowpath_null+0x15/0x17
> [ 153.923579] [<ffffffff814afe73>] qdisc_list_add+0x79/0xcf
> [ 153.925134] [<ffffffff814b1466>] qdisc_create+0x237/0x350
> [ 153.926658] [<ffffffff814b1a05>] tc_modify_qdisc+0x486/0x4af
> [ 153.928173] [<ffffffff814a2bb0>] rtnetlink_rcv_msg+0x180/0x193
> [ 153.929753] [<ffffffff810c7c32>] ? trace_preempt_on+0x12/0x2f
> [ 153.931453] [<ffffffff814a2a30>] ? rtnl_newlink+0x4ba/0x4ba
> [ 153.933107] [<ffffffff814b67e4>] netlink_rcv_skb+0x44/0x86
> [ 153.934586] [<ffffffff8149fbeb>] rtnetlink_rcv+0x1e/0x25
> [ 153.936133] [<ffffffff814b62ef>] netlink_unicast+0xf1/0x175
> [ 153.937587] [<ffffffff814b6677>] netlink_sendmsg+0x304/0x34e
> [ 153.939088] [<ffffffff814794ac>] __sock_sendmsg_nosec+0x25/0x27
> [ 153.940638] [<ffffffff8147b0c2>] sock_sendmsg+0x52/0x6c
> [ 153.942278] [<ffffffff811009ce>] ? might_fault+0x9b/0x9f
> [ 153.943980] [<ffffffff81100985>] ? might_fault+0x52/0x9f
> [ 153.945439] [<ffffffff81487cec>] ? verify_iovec+0x5e/0xac
> [ 153.946993] [<ffffffff8147cd41>] ___sys_sendmsg+0x20d/0x29d
> [ 153.948540] [<ffffffff81073236>] ? arch_local_irq_save+0x9/0xc
> [ 153.950087] [<ffffffff81072708>] ? up_read+0x22/0x25
> [ 153.951743] [<ffffffff8165a21b>] ? __do_page_fault+0x56f/0x600
> [ 153.953495] [<ffffffff810c7bdd>] ? time_hardirqs_on+0x1b/0x2f
> [ 153.955175] [<ffffffff8113fdee>] ? fcheck_files+0x80/0xe0
> [ 153.956720] [<ffffffff8114062d>] ? fget_light+0x30/0x90
> [ 153.958195] [<ffffffff8147d20a>] __sys_sendmsg+0x3d/0x5b
> [ 153.959645] [<ffffffff8147d235>] SyS_sendmsg+0xd/0x17
> [ 153.961092] [<ffffffff8165d722>] system_call_fastpath+0x16/0x1b
> [ 153.965229] ---[ end trace ec29ec2eecd5a461 ]---
>
Thanks for the report !
Could you try the following patch ?
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index c31190e29b90..17c03198ebbc 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -273,11 +273,12 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
void qdisc_list_add(struct Qdisc *q)
{
- struct Qdisc *root = qdisc_dev(q)->qdisc;
+ if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+ struct Qdisc *root = qdisc_dev(q)->qdisc;
- WARN_ON_ONCE(root == &noop_qdisc);
- if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
+ WARN_ON_ONCE(root == &noop_qdisc);
list_add_tail(&q->list, &root->list);
+ }
}
EXPORT_SYMBOL(qdisc_list_add);
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH net] pkt_sched: move the sanity test in qdisc_list_add()
2013-12-20 16:26 ` Eric Dumazet
@ 2014-03-08 16:01 ` Eric Dumazet
2014-03-10 19:44 ` David Miller
0 siblings, 1 reply; 4+ messages in thread
From: Eric Dumazet @ 2014-03-08 16:01 UTC (permalink / raw)
To: Valdis Kletnieks, David Miller, Mirco Tischler; +Cc: Eric Dumazet, netdev
From: Eric Dumazet <edumazet@google.com>
The WARN_ON(root == &noop_qdisc)) added in qdisc_list_add()
can trigger in normal conditions when devices are not up.
It should be done only right before the list_add_tail() call.
Fixes: e57a784d8cae4 ("pkt_sched: set root qdisc before change() in attach_default_qdiscs()")
Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Tested-by: Mirco Tischler <mt-ml@gmx.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
net/sched/sch_api.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index c31190e29b90..17c03198ebbc 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -273,11 +273,12 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle)
void qdisc_list_add(struct Qdisc *q)
{
- struct Qdisc *root = qdisc_dev(q)->qdisc;
+ if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) {
+ struct Qdisc *root = qdisc_dev(q)->qdisc;
- WARN_ON_ONCE(root == &noop_qdisc);
- if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS))
+ WARN_ON_ONCE(root == &noop_qdisc);
list_add_tail(&q->list, &root->list);
+ }
}
EXPORT_SYMBOL(qdisc_list_add);
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH net] pkt_sched: move the sanity test in qdisc_list_add()
2014-03-08 16:01 ` [PATCH net] pkt_sched: move the sanity test in qdisc_list_add() Eric Dumazet
@ 2014-03-10 19:44 ` David Miller
0 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2014-03-10 19:44 UTC (permalink / raw)
To: eric.dumazet; +Cc: Valdis.Kletnieks, mt-ml, edumazet, netdev
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 08 Mar 2014 08:01:19 -0800
> From: Eric Dumazet <edumazet@google.com>
>
> The WARN_ON(root == &noop_qdisc)) added in qdisc_list_add()
> can trigger in normal conditions when devices are not up.
> It should be done only right before the list_add_tail() call.
>
> Fixes: e57a784d8cae4 ("pkt_sched: set root qdisc before change() in attach_default_qdiscs()")
> Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
> Tested-by: Mirco Tischler <mt-ml@gmx.de>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, thanks Eric.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-03-10 19:44 UTC | newest]
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2013-12-19 18:14 next-20131218 - WARNING in qdisc_list_add Valdis Kletnieks
2013-12-20 16:26 ` Eric Dumazet
2014-03-08 16:01 ` [PATCH net] pkt_sched: move the sanity test in qdisc_list_add() Eric Dumazet
2014-03-10 19:44 ` David Miller
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