user/sven/linux.git/include/net/sch_generic.h, branch stable/4.3.y

net_sched: fix qdisc_tree_decrease_qlen() races

2015-12-15T05:41:04Z

[ Upstream commit 4eaf3b84f2881c9c028f1d5e76c52ab575fe3a66 ] qdisc_tree_decrease_qlen() suffers from two problems on multiqueue devices. One problem is that it updates sch->q.qlen and sch->qstats.drops on the mq/mqprio root qdisc, while it should not : Daniele reported underflows errors : [ 681.774821] PAX: sch->q.qlen: 0 n: 1 [ 681.774825] PAX: size overflow detected in function qdisc_tree_decrease_qlen net/sched/sch_api.c:769 cicus.693_49 min, count: 72, decl: qlen; num: 0; context: sk_buff_head; [ 681.774954] CPU: 2 PID: 19 Comm: ksoftirqd/2 Tainted: G O 4.2.6.201511282239-1-grsec #1 [ 681.774955] Hardware name: ASUSTeK COMPUTER INC. X302LJ/X302LJ, BIOS X302LJ.202 03/05/2015 [ 681.774956] ffffffffa9a04863 0000000000000000 0000000000000000 ffffffffa990ff7c [ 681.774959] ffffc90000d3bc38 ffffffffa95d2810 0000000000000007 ffffffffa991002b [ 681.774960] ffffc90000d3bc68 ffffffffa91a44f4 0000000000000001 0000000000000001 [ 681.774962] Call Trace: [ 681.774967] [] dump_stack+0x4c/0x7f [ 681.774970] [] report_size_overflow+0x34/0x50 [ 681.774972] [] qdisc_tree_decrease_qlen+0x152/0x160 [ 681.774976] [] fq_codel_dequeue+0x7b1/0x820 [sch_fq_codel] [ 681.774978] [] ? qdisc_peek_dequeued+0xa0/0xa0 [sch_fq_codel] [ 681.774980] [] __qdisc_run+0x4d/0x1d0 [ 681.774983] [] net_tx_action+0xc2/0x160 [ 681.774985] [] __do_softirq+0xf1/0x200 [ 681.774987] [] run_ksoftirqd+0x1e/0x30 [ 681.774989] [] smpboot_thread_fn+0x150/0x260 [ 681.774991] [] ? sort_range+0x40/0x40 [ 681.774992] [] kthread+0xe4/0x100 [ 681.774994] [] ? kthread_worker_fn+0x170/0x170 [ 681.774995] [] ret_from_fork+0x3e/0x70 mq/mqprio have their own ways to report qlen/drops by folding stats on all their queues, with appropriate locking. A second problem is that qdisc_tree_decrease_qlen() calls qdisc_lookup() without proper locking : concurrent qdisc updates could corrupt the list that qdisc_match_from_root() parses to find a qdisc given its handle. Fix first problem adding a TCQ_F_NOPARENT qdisc flag that qdisc_tree_decrease_qlen() can use to abort its tree traversal, as soon as it meets a mq/mqprio qdisc children. Second problem can be fixed by RCU protection. Qdisc are already freed after RCU grace period, so qdisc_list_add() and qdisc_list_del() simply have to use appropriate rcu list variants. A future patch will add a per struct netdev_queue list anchor, so that qdisc_tree_decrease_qlen() can have more efficient lookups. Reported-by: Daniele Fucini Signed-off-by: Eric Dumazet Cc: Cong Wang Cc: Jamal Hadi Salim Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: sched: register noqueue qdisc

2015-08-28T00:14:30Z

This way users can attach noqueue just like any other qdisc using tc without having to mess with tx_queue_len first. Signed-off-by: Phil Sutter Signed-off-by: David S. Miller

net: sched: extend percpu stats helpers

2015-07-08T20:50:41Z

qdisc_bstats_update_cpu() and other helpers were added to support percpu stats for qdisc. We want to add percpu stats for tc action, so this patch add common helpers. qdisc_bstats_update_cpu() is renamed to qdisc_bstats_cpu_update() qdisc_qstats_drop_cpu() is renamed to qdisc_qstats_cpu_drop() Signed-off-by: Eric Dumazet Cc: Alexei Starovoitov Acked-by: Jamal Hadi Salim Acked-by: John Fastabend Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

net: sched: use counter to break reclassify loops

2015-05-13T19:08:14Z

Seems all we want here is to avoid endless 'goto reclassify' loop. tc_classify_compat even resets this counter when something other than TC_ACT_RECLASSIFY is returned, so this skb-counter doesn't break hypothetical loops induced by something other than perpetual TC_ACT_RECLASSIFY return values. skb_act_clone is now identical to skb_clone, so just use that. Tested with following (bogus) filter: tc filter add dev eth0 parent ffff: \ protocol ip u32 match u32 0 0 police rate 10Kbit burst \ 64000 mtu 1500 action reclassify Acked-by: Daniel Borkmann Signed-off-by: Florian Westphal Acked-by: Alexei Starovoitov Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: deprecate enqueue_root()

2015-05-11T18:17:32Z

Only left enqueue_root() user is netem, and it looks not necessary : qdisc_skb_cb(skb)->pkt_len is preserved after one skb_clone() Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net: sched: remove TC_MUNGED bits

2015-05-03T02:25:17Z

Not used. pedit sets TC_MUNGED when packet content was altered, but all the core does is unset MUNGED again and then set OK2MUNGE. And the latter isn't tested anywhere. So lets remove both TC_MUNGED and TC_OK2MUNGE. Signed-off-by: Florian Westphal Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net_sched: destroy proto tp when all filters are gone

2015-03-09T19:35:55Z

Kernel automatically creates a tp for each (kind, protocol, priority) tuple, which has handle 0, when we add a new filter, but it still is left there after we remove our own, unless we don't specify the handle (literally means all the filters under the tuple). For example this one is left: # tc filter show dev eth0 filter parent 8001: protocol arp pref 49152 basic The user-space is hard to clean up these for kernel because filters like u32 are organized in a complex way. So kernel is responsible to remove it after all filters are gone. Each type of filter has its own way to store the filters, so each type has to provide its way to check if all filters are gone. Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net: sched: fix panic in rate estimators

2015-02-01T01:49:37Z

Doing the following commands on a non idle network device panics the box instantly, because cpu_bstats gets overwritten by stats. tc qdisc add dev eth0 root ... some traffic (one packet is enough) ... tc qdisc replace dev eth0 root est 1sec 4sec [ 325.355596] BUG: unable to handle kernel paging request at ffff8841dc5a074c [ 325.362609] IP: [] __gnet_stats_copy_basic+0x3e/0x90 [ 325.369158] PGD 1fa7067 PUD 0 [ 325.372254] Oops: 0000 [#1] SMP [ 325.375514] Modules linked in: ... [ 325.398346] CPU: 13 PID: 14313 Comm: tc Not tainted 3.19.0-smp-DEV #1163 [ 325.412042] task: ffff8800793ab5d0 ti: ffff881ff2fa4000 task.ti: ffff881ff2fa4000 [ 325.419518] RIP: 0010:[] [] __gnet_stats_copy_basic+0x3e/0x90 [ 325.428506] RSP: 0018:ffff881ff2fa7928 EFLAGS: 00010286 [ 325.433824] RAX: 000000000000000c RBX: ffff881ff2fa796c RCX: 000000000000000c [ 325.440988] RDX: ffff8841dc5a0744 RSI: 0000000000000060 RDI: 0000000000000060 [ 325.448120] RBP: ffff881ff2fa7948 R08: ffffffff81cd4f80 R09: 0000000000000000 [ 325.455268] R10: ffff883ff223e400 R11: 0000000000000000 R12: 000000015cba0744 [ 325.462405] R13: ffffffff81cd4f80 R14: ffff883ff223e460 R15: ffff883feea0722c [ 325.469536] FS: 00007f2ee30fa700(0000) GS:ffff88407fa20000(0000) knlGS:0000000000000000 [ 325.477630] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 325.483380] CR2: ffff8841dc5a074c CR3: 0000003feeae9000 CR4: 00000000001407e0 [ 325.490510] Stack: [ 325.492524] ffff883feea0722c ffff883fef719dc0 ffff883feea0722c ffff883ff223e4a0 [ 325.499990] ffff881ff2fa79a8 ffffffff815424ee ffff883ff223e49c 000000015cba0744 [ 325.507460] 00000000f2fa7978 0000000000000000 ffff881ff2fa79a8 ffff883ff223e4a0 [ 325.514956] Call Trace: [ 325.517412] [] gen_new_estimator+0x8e/0x230 [ 325.523250] [] gen_replace_estimator+0x4a/0x60 [ 325.529349] [] tc_modify_qdisc+0x52b/0x590 [ 325.535117] [] rtnetlink_rcv_msg+0xa0/0x240 [ 325.540963] [] ? __rtnl_unlock+0x20/0x20 [ 325.546532] [] netlink_rcv_skb+0xb1/0xc0 [ 325.552145] [] rtnetlink_rcv+0x25/0x40 [ 325.557558] [] netlink_unicast+0x168/0x220 [ 325.563317] [] netlink_sendmsg+0x2ec/0x3e0 Lets play safe and not use an union : percpu 'pointers' are mostly read anyway, and we have typically few qdiscs per host. Signed-off-by: Eric Dumazet Cc: John Fastabend Fixes: 22e0f8b9322c ("net: sched: make bstats per cpu and estimator RCU safe") Signed-off-by: David S. Miller

net: sched: cls: remove unused op put from tcf_proto_ops

2014-12-09T19:49:02Z

It is never called and implementations are void. So just remove it. Signed-off-by: Jiri Pirko Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller

qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE

2014-10-03T19:37:06Z

Based on DaveM's recent API work on dev_hard_start_xmit(), that allows sending/processing an entire skb list. This patch implements qdisc bulk dequeue, by allowing multiple packets to be dequeued in dequeue_skb(). The optimization principle for this is two fold, (1) to amortize locking cost and (2) avoid expensive tailptr update for notifying HW. (1) Several packets are dequeued while holding the qdisc root_lock, amortizing locking cost over several packet. The dequeued SKB list is processed under the TXQ lock in dev_hard_start_xmit(), thus also amortizing the cost of the TXQ lock. (2) Further more, dev_hard_start_xmit() will utilize the skb->xmit_more API to delay HW tailptr update, which also reduces the cost per packet. One restriction of the new API is that every SKB must belong to the same TXQ. This patch takes the easy way out, by restricting bulk dequeue to qdisc's with the TCQ_F_ONETXQUEUE flag, that specifies the qdisc only have attached a single TXQ. Some detail about the flow; dev_hard_start_xmit() will process the skb list, and transmit packets individually towards the driver (see xmit_one()). In case the driver stops midway in the list, the remaining skb list is returned by dev_hard_start_xmit(). In sch_direct_xmit() this returned list is requeued by dev_requeue_skb(). To avoid overshooting the HW limits, which results in requeuing, the patch limits the amount of bytes dequeued, based on the drivers BQL limits. In-effect bulking will only happen for BQL enabled drivers. Small amounts for extra HoL blocking (2x MTU/0.24ms) were measured at 100Mbit/s, with bulking 8 packets, but the oscillating nature of the measurement indicate something, like sched latency might be causing this effect. More comparisons show, that this oscillation goes away occationally. Thus, we disregard this artifact completely and remove any "magic" bulking limit. For now, as a conservative approach, stop bulking when seeing TSO and segmented GSO packets. They already benefit from bulking on their own. A followup patch add this, to allow easier bisect-ability for finding regressions. Jointed work with Hannes, Daniel and Florian. Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Hannes Frederic Sowa Signed-off-by: Daniel Borkmann Signed-off-by: Florian Westphal Signed-off-by: David S. Miller