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2019-03-13net: netem: fix skb length BUG_ON in __skb_to_sgvecSheng Lan
[ Upstream commit 5845f706388a4cde0f6b80f9e5d33527e942b7d9 ] It can be reproduced by following steps: 1. virtio_net NIC is configured with gso/tso on 2. configure nginx as http server with an index file bigger than 1M bytes 3. use tc netem to produce duplicate packets and delay: tc qdisc add dev eth0 root netem delay 100ms 10ms 30% duplicate 90% 4. continually curl the nginx http server to get index file on client 5. BUG_ON is seen quickly [10258690.371129] kernel BUG at net/core/skbuff.c:4028! [10258690.371748] invalid opcode: 0000 [#1] SMP PTI [10258690.372094] CPU: 5 PID: 0 Comm: swapper/5 Tainted: G W 5.0.0-rc6 #2 [10258690.372094] RSP: 0018:ffffa05797b43da0 EFLAGS: 00010202 [10258690.372094] RBP: 00000000000005ea R08: 0000000000000000 R09: 00000000000005ea [10258690.372094] R10: ffffa0579334d800 R11: 00000000000002c0 R12: 0000000000000002 [10258690.372094] R13: 0000000000000000 R14: ffffa05793122900 R15: ffffa0578f7cb028 [10258690.372094] FS: 0000000000000000(0000) GS:ffffa05797b40000(0000) knlGS:0000000000000000 [10258690.372094] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [10258690.372094] CR2: 00007f1a6dc00868 CR3: 000000001000e000 CR4: 00000000000006e0 [10258690.372094] Call Trace: [10258690.372094] <IRQ> [10258690.372094] skb_to_sgvec+0x11/0x40 [10258690.372094] start_xmit+0x38c/0x520 [virtio_net] [10258690.372094] dev_hard_start_xmit+0x9b/0x200 [10258690.372094] sch_direct_xmit+0xff/0x260 [10258690.372094] __qdisc_run+0x15e/0x4e0 [10258690.372094] net_tx_action+0x137/0x210 [10258690.372094] __do_softirq+0xd6/0x2a9 [10258690.372094] irq_exit+0xde/0xf0 [10258690.372094] smp_apic_timer_interrupt+0x74/0x140 [10258690.372094] apic_timer_interrupt+0xf/0x20 [10258690.372094] </IRQ> In __skb_to_sgvec(), the skb->len is not equal to the sum of the skb's linear data size and nonlinear data size, thus BUG_ON triggered. Because the skb is cloned and a part of nonlinear data is split off. Duplicate packet is cloned in netem_enqueue() and may be delayed some time in qdisc. When qdisc len reached the limit and returns NET_XMIT_DROP, the skb will be retransmit later in write queue. the skb will be fragmented by tso_fragment(), the limit size that depends on cwnd and mss decrease, the skb's nonlinear data will be split off. The length of the skb cloned by netem will not be updated. When we use virtio_net NIC and invoke skb_to_sgvec(), the BUG_ON trigger. To fix it, netem returns NET_XMIT_SUCCESS to upper stack when it clones a duplicate packet. Fixes: 35d889d1 ("sch_netem: fix skb leak in netem_enqueue()") Signed-off-by: Sheng Lan <lansheng@huawei.com> Reported-by: Qin Ji <jiqin.ji@huawei.com> Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-17net: Prevent invalid access to skb->prev in __qdisc_drop_allChristoph Paasch
[ Upstream commit 9410d386d0a829ace9558336263086c2fbbe8aed ] __qdisc_drop_all() accesses skb->prev to get to the tail of the segment-list. With commit 68d2f84a1368 ("net: gro: properly remove skb from list") the skb-list handling has been changed to set skb->next to NULL and set the list-poison on skb->prev. With that change, __qdisc_drop_all() will panic when it tries to dereference skb->prev. Since commit 992cba7e276d ("net: Add and use skb_list_del_init().") __list_del_entry is used, leaving skb->prev unchanged (thus, pointing to the list-head if it's the first skb of the list). This will make __qdisc_drop_all modify the next-pointer of the list-head and result in a panic later on: [ 34.501053] general protection fault: 0000 [#1] SMP KASAN PTI [ 34.501968] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.20.0-rc2.mptcp #108 [ 34.502887] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011 [ 34.504074] RIP: 0010:dev_gro_receive+0x343/0x1f90 [ 34.504751] Code: e0 48 c1 e8 03 42 80 3c 30 00 0f 85 4a 1c 00 00 4d 8b 24 24 4c 39 65 d0 0f 84 0a 04 00 00 49 8d 7c 24 38 48 89 f8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 74 08 3c 04 [ 34.507060] RSP: 0018:ffff8883af507930 EFLAGS: 00010202 [ 34.507761] RAX: 0000000000000007 RBX: ffff8883970b2c80 RCX: 1ffff11072e165a6 [ 34.508640] RDX: 1ffff11075867008 RSI: ffff8883ac338040 RDI: 0000000000000038 [ 34.509493] RBP: ffff8883af5079d0 R08: ffff8883970b2d40 R09: 0000000000000062 [ 34.510346] R10: 0000000000000034 R11: 0000000000000000 R12: 0000000000000000 [ 34.511215] R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8883ac338008 [ 34.512082] FS: 0000000000000000(0000) GS:ffff8883af500000(0000) knlGS:0000000000000000 [ 34.513036] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 34.513741] CR2: 000055ccc3e9d020 CR3: 00000003abf32000 CR4: 00000000000006e0 [ 34.514593] Call Trace: [ 34.514893] <IRQ> [ 34.515157] napi_gro_receive+0x93/0x150 [ 34.515632] receive_buf+0x893/0x3700 [ 34.516094] ? __netif_receive_skb+0x1f/0x1a0 [ 34.516629] ? virtnet_probe+0x1b40/0x1b40 [ 34.517153] ? __stable_node_chain+0x4d0/0x850 [ 34.517684] ? kfree+0x9a/0x180 [ 34.518067] ? __kasan_slab_free+0x171/0x190 [ 34.518582] ? detach_buf+0x1df/0x650 [ 34.519061] ? lapic_next_event+0x5a/0x90 [ 34.519539] ? virtqueue_get_buf_ctx+0x280/0x7f0 [ 34.520093] virtnet_poll+0x2df/0xd60 [ 34.520533] ? receive_buf+0x3700/0x3700 [ 34.521027] ? qdisc_watchdog_schedule_ns+0xd5/0x140 [ 34.521631] ? htb_dequeue+0x1817/0x25f0 [ 34.522107] ? sch_direct_xmit+0x142/0xf30 [ 34.522595] ? virtqueue_napi_schedule+0x26/0x30 [ 34.523155] net_rx_action+0x2f6/0xc50 [ 34.523601] ? napi_complete_done+0x2f0/0x2f0 [ 34.524126] ? kasan_check_read+0x11/0x20 [ 34.524608] ? _raw_spin_lock+0x7d/0xd0 [ 34.525070] ? _raw_spin_lock_bh+0xd0/0xd0 [ 34.525563] ? kvm_guest_apic_eoi_write+0x6b/0x80 [ 34.526130] ? apic_ack_irq+0x9e/0xe0 [ 34.526567] __do_softirq+0x188/0x4b5 [ 34.527015] irq_exit+0x151/0x180 [ 34.527417] do_IRQ+0xdb/0x150 [ 34.527783] common_interrupt+0xf/0xf [ 34.528223] </IRQ> This patch makes sure that skb->prev is set to NULL when entering netem_enqueue. Cc: Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Cc: Tyler Hicks <tyhicks@canonical.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Fixes: 68d2f84a1368 ("net: gro: properly remove skb from list") Suggested-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: Christoph Paasch <cpaasch@apple.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-09-15sch_netem: avoid null pointer deref on init failureNikolay Aleksandrov
commit 634576a1844dba15bc5e6fc61d72f37e13a21615 upstream. netem can fail in ->init due to missing options (either not supplied by user-space or used as a default qdisc) causing a timer->base null pointer deref in its ->destroy() and ->reset() callbacks. Reproduce: $ sysctl net.core.default_qdisc=netem $ ip l set ethX up Crash log: [ 1814.846943] BUG: unable to handle kernel NULL pointer dereference at (null) [ 1814.847181] IP: hrtimer_active+0x17/0x8a [ 1814.847270] PGD 59c34067 [ 1814.847271] P4D 59c34067 [ 1814.847337] PUD 37374067 [ 1814.847403] PMD 0 [ 1814.847468] [ 1814.847582] Oops: 0000 [#1] SMP [ 1814.847655] Modules linked in: sch_netem(O) sch_fq_codel(O) [ 1814.847761] CPU: 3 PID: 1573 Comm: ip Tainted: G O 4.13.0-rc6+ #62 [ 1814.847884] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 1814.848043] task: ffff88003723a700 task.stack: ffff88005adc8000 [ 1814.848235] RIP: 0010:hrtimer_active+0x17/0x8a [ 1814.848407] RSP: 0018:ffff88005adcb590 EFLAGS: 00010246 [ 1814.848590] RAX: 0000000000000000 RBX: ffff880058e359d8 RCX: 0000000000000000 [ 1814.848793] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff880058e359d8 [ 1814.848998] RBP: ffff88005adcb5b0 R08: 00000000014080c0 R09: 00000000ffffffff [ 1814.849204] R10: ffff88005adcb660 R11: 0000000000000020 R12: 0000000000000000 [ 1814.849410] R13: ffff880058e359d8 R14: 00000000ffffffff R15: 0000000000000001 [ 1814.849616] FS: 00007f733bbca740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000 [ 1814.849919] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1814.850107] CR2: 0000000000000000 CR3: 0000000059f0d000 CR4: 00000000000406e0 [ 1814.850313] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1814.850518] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1814.850723] Call Trace: [ 1814.850875] hrtimer_try_to_cancel+0x1a/0x93 [ 1814.851047] hrtimer_cancel+0x15/0x20 [ 1814.851211] qdisc_watchdog_cancel+0x12/0x14 [ 1814.851383] netem_reset+0xe6/0xed [sch_netem] [ 1814.851561] qdisc_destroy+0x8b/0xe5 [ 1814.851723] qdisc_create_dflt+0x86/0x94 [ 1814.851890] ? dev_activate+0x129/0x129 [ 1814.852057] attach_one_default_qdisc+0x36/0x63 [ 1814.852232] netdev_for_each_tx_queue+0x3d/0x48 [ 1814.852406] dev_activate+0x4b/0x129 [ 1814.852569] __dev_open+0xe7/0x104 [ 1814.852730] __dev_change_flags+0xc6/0x15c [ 1814.852899] dev_change_flags+0x25/0x59 [ 1814.853064] do_setlink+0x30c/0xb3f [ 1814.853228] ? check_chain_key+0xb0/0xfd [ 1814.853396] ? check_chain_key+0xb0/0xfd [ 1814.853565] rtnl_newlink+0x3a4/0x729 [ 1814.853728] ? rtnl_newlink+0x117/0x729 [ 1814.853905] ? ns_capable_common+0xd/0xb1 [ 1814.854072] ? ns_capable+0x13/0x15 [ 1814.854234] rtnetlink_rcv_msg+0x188/0x197 [ 1814.854404] ? rcu_read_unlock+0x3e/0x5f [ 1814.854572] ? rtnl_newlink+0x729/0x729 [ 1814.854737] netlink_rcv_skb+0x6c/0xce [ 1814.854902] rtnetlink_rcv+0x23/0x2a [ 1814.855064] netlink_unicast+0x103/0x181 [ 1814.855230] netlink_sendmsg+0x326/0x337 [ 1814.855398] sock_sendmsg_nosec+0x14/0x3f [ 1814.855584] sock_sendmsg+0x29/0x2e [ 1814.855747] ___sys_sendmsg+0x209/0x28b [ 1814.855912] ? do_raw_spin_unlock+0xcd/0xf8 [ 1814.856082] ? _raw_spin_unlock+0x27/0x31 [ 1814.856251] ? __handle_mm_fault+0x651/0xdb1 [ 1814.856421] ? check_chain_key+0xb0/0xfd [ 1814.856592] __sys_sendmsg+0x45/0x63 [ 1814.856755] ? __sys_sendmsg+0x45/0x63 [ 1814.856923] SyS_sendmsg+0x19/0x1b [ 1814.857083] entry_SYSCALL_64_fastpath+0x23/0xc2 [ 1814.857256] RIP: 0033:0x7f733b2dd690 [ 1814.857419] RSP: 002b:00007ffe1d3387d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 1814.858238] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f733b2dd690 [ 1814.858445] RDX: 0000000000000000 RSI: 00007ffe1d338820 RDI: 0000000000000003 [ 1814.858651] RBP: ffff88005adcbf98 R08: 0000000000000001 R09: 0000000000000003 [ 1814.858856] R10: 00007ffe1d3385a0 R11: 0000000000000246 R12: 0000000000000002 [ 1814.859060] R13: 000000000066f1a0 R14: 00007ffe1d3408d0 R15: 0000000000000000 [ 1814.859267] ? trace_hardirqs_off_caller+0xa7/0xcf [ 1814.859446] Code: 10 55 48 89 c7 48 89 e5 e8 45 a1 fb ff 31 c0 5d c3 31 c0 c3 66 66 66 66 90 55 48 89 e5 41 56 41 55 41 54 53 49 89 fd 49 8b 45 30 <4c> 8b 20 41 8b 5c 24 38 31 c9 31 d2 48 c7 c7 50 8e 1d 82 41 89 [ 1814.860022] RIP: hrtimer_active+0x17/0x8a RSP: ffff88005adcb590 [ 1814.860214] CR2: 0000000000000000 Fixes: 87b60cfacf9f ("net_sched: fix error recovery at qdisc creation") Fixes: 0fbbeb1ba43b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()") Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Amit Pundir <amit.pundir@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-31sch_netem: fix skb leak in netem_enqueue()Alexey Kodanev
[ Upstream commit 35d889d10b649fda66121891ec05eca88150059d ] When we exceed current packets limit and we have more than one segment in the list returned by skb_gso_segment(), netem drops only the first one, skipping the rest, hence kmemleak reports: unreferenced object 0xffff880b5d23b600 (size 1024): comm "softirq", pid 0, jiffies 4384527763 (age 2770.629s) hex dump (first 32 bytes): 00 80 23 5d 0b 88 ff ff 00 00 00 00 00 00 00 00 ..#]............ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000d8a19b9d>] __alloc_skb+0xc9/0x520 [<000000001709b32f>] skb_segment+0x8c8/0x3710 [<00000000c7b9bb88>] tcp_gso_segment+0x331/0x1830 [<00000000c921cba1>] inet_gso_segment+0x476/0x1370 [<000000008b762dd4>] skb_mac_gso_segment+0x1f9/0x510 [<000000002182660a>] __skb_gso_segment+0x1dd/0x620 [<00000000412651b9>] netem_enqueue+0x1536/0x2590 [sch_netem] [<0000000005d3b2a9>] __dev_queue_xmit+0x1167/0x2120 [<00000000fc5f7327>] ip_finish_output2+0x998/0xf00 [<00000000d309e9d3>] ip_output+0x1aa/0x2c0 [<000000007ecbd3a4>] tcp_transmit_skb+0x18db/0x3670 [<0000000042d2a45f>] tcp_write_xmit+0x4d4/0x58c0 [<0000000056a44199>] tcp_tasklet_func+0x3d9/0x540 [<0000000013d06d02>] tasklet_action+0x1ca/0x250 [<00000000fcde0b8b>] __do_softirq+0x1b4/0x5a3 [<00000000e7ed027c>] irq_exit+0x1e2/0x210 Fix it by adding the rest of the segments, if any, to skb 'to_free' list. Add new __qdisc_drop_all() and qdisc_drop_all() functions because they can be useful in the future if we need to drop segmented GSO packets in other places. Fixes: 6071bd1aa13e ("netem: Segment GSO packets on enqueue") Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-22netem: apply correct delay when rate throttlingNik Unger
[ Upstream commit 5080f39e8c72e01cf37e8359023e7018e2a4901e ] I recently reported on the netem list that iperf network benchmarks show unexpected results when a bandwidth throttling rate has been configured for netem. Specifically: 1) The measured link bandwidth *increases* when a higher delay is added 2) The measured link bandwidth appears higher than the specified limit 3) The measured link bandwidth for the same very slow settings varies significantly across machines The issue can be reproduced by using tc to configure netem with a 512kbit rate and various (none, 1us, 50ms, 100ms, 200ms) delays on a veth pair between network namespaces, and then using iperf (or any other network benchmarking tool) to test throughput. Complete detailed instructions are in the original email chain here: https://lists.linuxfoundation.org/pipermail/netem/2017-February/001672.html There appear to be two underlying bugs causing these effects: - The first issue causes long delays when the rate is slow and no delay is configured (e.g., "rate 512kbit"). This is because SKBs are not orphaned when no delay is configured, so orphaning does not occur until *after* the rate-induced delay has been applied. For this reason, adding a tiny delay (e.g., "rate 512kbit delay 1us") dramatically increases the measured bandwidth. - The second issue is that rate-induced delays are not correctly applied, allowing SKB delays to occur in parallel. The indended approach is to compute the delay for an SKB and to add this delay to the end of the current queue. However, the code does not detect existing SKBs in the queue due to improperly testing sch->q.qlen, which is nonzero even when packets exist only in the rbtree. Consequently, new SKBs do not wait for the current queue to empty. When packet delays vary significantly (e.g., if packet sizes are different), then this also causes unintended reordering. I modified the code to expect a delay (and orphan the SKB) when a rate is configured. I also added some defensive tests that correctly find the latest scheduled delivery time, even if it is (unexpectedly) for a packet in sch->q. I have tested these changes on the latest kernel (4.11.0-rc1+) and the iperf / ping test results are as expected. Signed-off-by: Nik Unger <njunger@uwaterloo.ca> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-09-19sched: add and use qdisc_skb_head helpersFlorian Westphal
This change replaces sk_buff_head struct in Qdiscs with new qdisc_skb_head. Its similar to the skb_buff_head api, but does not use skb->prev pointers. Qdiscs will commonly enqueue at the tail of a list and dequeue at head. While skb_buff_head works fine for this, enqueue/dequeue needs to also adjust the prev pointer of next element. The ->prev pointer is not required for qdiscs so we can just leave it undefined and avoid one cacheline write access for en/dequeue. Suggested-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-19sched: replace __skb_dequeue with __qdisc_dequeue_headFlorian Westphal
After previous patch these functions are identical. Replace __skb_dequeue in qdiscs with __qdisc_dequeue_head. Next patch will then make __qdisc_dequeue_head handle single-linked list instead of strcut sk_buff_head argument. Doesn't change generated code. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-09-19sched: don't use skb queue helpersFlorian Westphal
A followup change will replace the sk_buff_head in the qdisc struct with a slightly different list. Use of the sk_buff_head helpers will thus cause compiler warnings. Open-code these accesses in an extra change to ease review. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-30Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Several cases of overlapping changes, except the packet scheduler conflicts which deal with the addition of the free list parameter to qdisc_enqueue(). Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-29net_sched: netem: do not call qdisc_drop() with a NULL skbEric Dumazet
If skb_unshare() fails, we call qdisc_drop() with a NULL skb, which is no longer supported. Fixes: 520ac30f4551 ("net_sched: drop packets after root qdisc lock is released") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-25net_sched: drop packets after root qdisc lock is releasedEric Dumazet
Qdisc performance suffers when packets are dropped at enqueue() time because drops (kfree_skb()) are done while qdisc lock is held, delaying a dequeue() draining the queue. Nominal throughput can be reduced by 50 % when this happens, at a time we would like the dequeue() to proceed as fast as possible. Even FQ is vulnerable to this problem, while one of FQ goals was to provide some flow isolation. This patch adds a 'struct sk_buff **to_free' parameter to all qdisc->enqueue(), and in qdisc_drop() helper. I measured a performance increase of up to 12 %, but this patch is a prereq so that future batches in enqueue() can fly. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-23netem: fix a use after freeEric Dumazet
If the packet was dropped by lower qdisc, then we must not access it later. Save qdisc_pkt_len(skb) in a temp variable. Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: WANG Cong <xiyou.wangcong@gmail.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-15net_sched: sch_netem: defer skb freeingEric Dumazet
rtnl_kfree_skbs() can be used in tfifo_reset() It would be nice if we could iterate through rb tree instead of removing one skb at a time, and build a single skb chain. But this is left for a future patch. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-10net_sched: remove generic throttled managementEric Dumazet
__QDISC_STATE_THROTTLED bit manipulation is rather expensive for HTB and few others. I already removed it for sch_fq in commit f2600cf02b5b ("net: sched: avoid costly atomic operation in fq_dequeue()") and so far nobody complained. When one ore more packets are stuck in one or more throttled HTB class, a htb dequeue() performs two atomic operations to clear/set __QDISC_STATE_THROTTLED bit, while root qdisc lock is held. Removing this pair of atomic operations bring me a 8 % performance increase on 200 TCP_RR tests, in presence of throttled classes. This patch has no side effect, since nothing actually uses disc_is_throttled() anymore. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-10net_sched: netem: remove qdisc_is_throttled() useEric Dumazet
Looks like it is only there as some optimization attempt. Since __QDISC_STATE_THROTTLED set/unset is way too expensive, and netem is the last user, just remove this check. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-08sched: remove qdisc->dropFlorian Westphal
after removal of TCA_CBQ_OVL_STRATEGY from cbq scheduler, there are no more callers of ->drop() outside of other ->drop functions, i.e. nothing calls them. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-06-08sched: remove qdisc_rehape_failFlorian Westphal
After the removal of TCA_CBQ_POLICE in cbq scheduler qdisc->reshape_fail is always NULL, i.e. qdisc_rehape_fail is now the same as qdisc_drop. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: net/ipv4/ip_gre.c Minor conflicts between tunnel bug fixes in net and ipv6 tunnel cleanups in net-next. Signed-off-by: David S. Miller <davem@davemloft.net>
2016-05-03netem: Segment GSO packets on enqueueNeil Horman
This was recently reported to me, and reproduced on the latest net kernel, when attempting to run netperf from a host that had a netem qdisc attached to the egress interface: [ 788.073771] ---------------------[ cut here ]--------------------------- [ 788.096716] WARNING: at net/core/dev.c:2253 skb_warn_bad_offload+0xcd/0xda() [ 788.129521] bnx2: caps=(0x00000001801949b3, 0x0000000000000000) len=2962 data_len=0 gso_size=1448 gso_type=1 ip_summed=3 [ 788.182150] Modules linked in: sch_netem kvm_amd kvm crc32_pclmul ipmi_ssif ghash_clmulni_intel sp5100_tco amd64_edac_mod aesni_intel lrw gf128mul glue_helper ablk_helper edac_mce_amd cryptd pcspkr sg edac_core hpilo ipmi_si i2c_piix4 k10temp fam15h_power hpwdt ipmi_msghandler shpchp acpi_power_meter pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt i2c_algo_bit drm_kms_helper ahci ata_generic pata_acpi ttm libahci crct10dif_pclmul pata_atiixp tg3 libata crct10dif_common drm crc32c_intel ptp serio_raw bnx2 r8169 hpsa pps_core i2c_core mii dm_mirror dm_region_hash dm_log dm_mod [ 788.465294] CPU: 16 PID: 0 Comm: swapper/16 Tainted: G W ------------ 3.10.0-327.el7.x86_64 #1 [ 788.511521] Hardware name: HP ProLiant DL385p Gen8, BIOS A28 12/17/2012 [ 788.542260] ffff880437c036b8 f7afc56532a53db9 ffff880437c03670 ffffffff816351f1 [ 788.576332] ffff880437c036a8 ffffffff8107b200 ffff880633e74200 ffff880231674000 [ 788.611943] 0000000000000001 0000000000000003 0000000000000000 ffff880437c03710 [ 788.647241] Call Trace: [ 788.658817] <IRQ> [<ffffffff816351f1>] dump_stack+0x19/0x1b [ 788.686193] [<ffffffff8107b200>] warn_slowpath_common+0x70/0xb0 [ 788.713803] [<ffffffff8107b29c>] warn_slowpath_fmt+0x5c/0x80 [ 788.741314] [<ffffffff812f92f3>] ? ___ratelimit+0x93/0x100 [ 788.767018] [<ffffffff81637f49>] skb_warn_bad_offload+0xcd/0xda [ 788.796117] [<ffffffff8152950c>] skb_checksum_help+0x17c/0x190 [ 788.823392] [<ffffffffa01463a1>] netem_enqueue+0x741/0x7c0 [sch_netem] [ 788.854487] [<ffffffff8152cb58>] dev_queue_xmit+0x2a8/0x570 [ 788.880870] [<ffffffff8156ae1d>] ip_finish_output+0x53d/0x7d0 ... The problem occurs because netem is not prepared to handle GSO packets (as it uses skb_checksum_help in its enqueue path, which cannot manipulate these frames). The solution I think is to simply segment the skb in a simmilar fashion to the way we do in __dev_queue_xmit (via validate_xmit_skb), with some minor changes. When we decide to corrupt an skb, if the frame is GSO, we segment it, corrupt the first segment, and enqueue the remaining ones. tested successfully by myself on the latest net kernel, to which this applies Signed-off-by: Neil Horman <nhorman@tuxdriver.com> CC: Jamal Hadi Salim <jhs@mojatatu.com> CC: "David S. Miller" <davem@davemloft.net> CC: netem@lists.linux-foundation.org CC: eric.dumazet@gmail.com CC: stephen@networkplumber.org Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-25sched: use nla_put_u64_64bit()Nicolas Dichtel
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: update hierarchical backlog tooWANG Cong
When the bottom qdisc decides to, for example, drop some packet, it calls qdisc_tree_decrease_qlen() to update the queue length for all its ancestors, we need to update the backlog too to keep the stats on root qdisc accurate. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-29net_sched: introduce qdisc_replace() helperWANG Cong
Remove nearly duplicated code and prepare for the following patch. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-11net: sched: deprecate enqueue_root()Eric Dumazet
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 <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-04-07netem: Fixes byte backlog accounting for the first of two chained netem ↵Beshay, Joseph
instances Fixes byte backlog accounting for the first of two chained netem instances. Bytes backlog reported now corresponds to the number of queued packets. When two netem instances are chained, for instance to apply rate and queue limitation followed by packet delay, the number of backlogged bytes reported by the first netem instance is wrong. It reports the sum of bytes in the queues of the first and second netem. The first netem reports the correct number of backlogged packets but not bytes. This is shown in the example below. Consider a chain of two netem schedulers created using the following commands: $ tc -s qdisc replace dev veth2 root handle 1:0 netem rate 10000kbit limit 100 $ tc -s qdisc add dev veth2 parent 1:0 handle 2: netem delay 50ms Start an iperf session to send packets out on the specified interface and monitor the backlog using tc: $ tc -s qdisc show dev veth2 Output using unpatched netem: qdisc netem 1: root refcnt 2 limit 100 rate 10000Kbit Sent 98422639 bytes 65434 pkt (dropped 123, overlimits 0 requeues 0) backlog 172694b 73p requeues 0 qdisc netem 2: parent 1: limit 1000 delay 50.0ms Sent 98422639 bytes 65434 pkt (dropped 0, overlimits 0 requeues 0) backlog 63588b 42p requeues 0 The interface used to produce this output has an MTU of 1500. The output for backlogged bytes behind netem 1 is 172694b. This value is not correct. Consider the total number of sent bytes and packets. By dividing the number of sent bytes by the number of sent packets, we get an average packet size of ~=1504. If we divide the number of backlogged bytes by packets, we get ~=2365. This is due to the first netem incorrectly counting the 63588b which are in netem 2's queue as being in its own queue. To verify this is the case, we subtract them from the reported value and divide by the number of packets as follows: 172694 - 63588 = 109106 bytes actualled backlogged in netem 1 109106 / 73 packets ~= 1494 bytes (which matches our MTU) The root cause is that the byte accounting is not done at the same time with packet accounting. The solution is to update the backlog value every time the packet queue is updated. Signed-off-by: Joseph D Beshay <joseph.beshay@utdallas.edu> Acked-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-11-03net: add rbnode to struct sk_buffEric Dumazet
Yaogong replaces TCP out of order receive queue by an RB tree. As netem already does a private skb->{next/prev/tstamp} union with a 'struct rb_node', lets do this in a cleaner way. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Yaogong Wang <wygivan@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-30net: sched: implement qstat helper routinesJohn Fastabend
This adds helpers to manipulate qstats logic and replaces locations that touch the counters directly. This simplifies future patches to push qstats onto per cpu counters. Signed-off-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-06-05net: use the new API kvfree()WANG Cong
It is available since v3.15-rc5. Cc: Pablo Neira Ayuso <pablo@netfilter.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-17sch_netem: replace magic numbers with enumerate in get_loss_clgYang Yingliang
Replace two magic numbers which intialize clgstate::state. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-14sch_netem: replace magic numbers with enumerate in GE modelYang Yingliang
Replace some magic numbers which describe states of GE model loss generator with enumerate. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-14sch_netem: change some func's param from "struct Qdisc *" to "struct ↵Yang Yingliang
netem_sched_data *" In netem_change(), we have already get "struct netem_sched_data *q". Replace params of get_correlation() and other similar functions with "struct netem_sched_data *q". Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-02-14sch_netem: return errcode before setting paramsYang Yingliang
get_dist_table() and get_loss_clg() may be failed. These two functions should be called after setting the members of qdisc_priv(sch), or it will break the old settings while either of them is failed. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-21reciprocal_divide: update/correction of the algorithmHannes Frederic Sowa
Jakub Zawadzki noticed that some divisions by reciprocal_divide() were not correct [1][2], which he could also show with BPF code after divisions are transformed into reciprocal_value() for runtime invariance which can be passed to reciprocal_divide() later on; reverse in BPF dump ended up with a different, off-by-one K in some situations. This has been fixed by Eric Dumazet in commit aee636c4809fa5 ("bpf: do not use reciprocal divide"). This follow-up patch improves reciprocal_value() and reciprocal_divide() to work in all cases by using Granlund and Montgomery method, so that also future use is safe and without any non-obvious side-effects. Known problems with the old implementation were that division by 1 always returned 0 and some off-by-ones when the dividend and divisor where very large. This seemed to not be problematic with its current users, as far as we can tell. Eric Dumazet checked for the slab usage, we cannot surely say so in the case of flex_array. Still, in order to fix that, we propose an extension from the original implementation from commit 6a2d7a955d8d resp. [3][4], by using the algorithm proposed in "Division by Invariant Integers Using Multiplication" [5], Torbjörn Granlund and Peter L. Montgomery, that is, pseudocode for q = n/d where q, n, d is in u32 universe: 1) Initialization: int l = ceil(log_2 d) uword m' = floor((1<<32)*((1<<l)-d)/d)+1 int sh_1 = min(l,1) int sh_2 = max(l-1,0) 2) For q = n/d, all uword: uword t = (n*m')>>32 q = (t+((n-t)>>sh_1))>>sh_2 The assembler implementation from Agner Fog [6] also helped a lot while implementing. We have tested the implementation on x86_64, ppc64, i686, s390x; on x86_64/haswell we're still half the latency compared to normal divide. Joint work with Daniel Borkmann. [1] http://www.wireshark.org/~darkjames/reciprocal-buggy.c [2] http://www.wireshark.org/~darkjames/set-and-dump-filter-k-bug.c [3] https://gmplib.org/~tege/division-paper.pdf [4] http://homepage.cs.uiowa.edu/~jones/bcd/divide.html [5] http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1.2556 [6] http://www.agner.org/optimize/asmlib.zip Reported-by: Jakub Zawadzki <darkjames-ws@darkjames.pl> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Austin S Hemmelgarn <ahferroin7@gmail.com> Cc: linux-kernel@vger.kernel.org Cc: Jesse Gross <jesse@nicira.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andy Gospodarek <andy@greyhouse.net> Cc: Veaceslav Falico <vfalico@redhat.com> Cc: Jay Vosburgh <fubar@us.ibm.com> Cc: Jakub Zawadzki <darkjames-ws@darkjames.pl> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-19sch_netem: replace magic numbers with enumerateYang Yingliang
Replace some magic numbers which describe states of 4-state model loss generator with enumerate. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-01-14net: replace macros net_random and net_srandom with direct calls to prandomAruna-Hewapathirane
This patch removes the net_random and net_srandom macros and replaces them with direct calls to the prandom ones. As new commits only seem to use prandom_u32 there is no use to keep them around. This change makes it easier to grep for users of prandom_u32. Signed-off-by: Aruna-Hewapathirane <aruna.hewapathirane@gmail.com> Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-31sch_netem: support of 64bit ratesYang Yingliang
Add a new attribute to support 64bit rates so that tc can use them to break the 32bit limit. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Acked-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-31sch_netem: more precise length of packetsYang Yingliang
With TSO/GSO/GRO packets, skb->len doesn't represent a precise amount of bytes on wire. This patch replace skb->len with qdisc_pkt_len(skb) which is more precise. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Acked-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-12-10net_sched: add space around '>' and before '('Yang Yingliang
Spaces required around that '>' (ctx:VxV) and before the open parenthesis '('. Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-30netem: fix gemodel loss generatorstephen hemminger
Patch from developers of the alternative loss models, downloaded from: http://netgroup.uniroma2.it/twiki/bin/view.cgi/Main/NetemCLG "in case 2, of the switch we change the direction of the inequality to net_random()>clg->a3, because clg->a3 is h in the GE model and when h is 0 all packets will be lost." Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-30netem: fix loss 4 state modelstephen hemminger
Patch from developers of the alternative loss models, downloaded from: http://netgroup.uniroma2.it/twiki/bin/view.cgi/Main/NetemCLG "In the case 1 of the switch statement in the if conditions we need to add clg->a4 to clg->a1, according to the model." Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-30netem: missing break in ge loss generatorstephen hemminger
There is a missing break statement in the Gilbert Elliot loss model generator which makes state machine behave incorrectly. Reported-by: Martin Burri <martin.burri@ch.abb.com Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-25netem: markov loss model transition fixHagen Paul Pfeifer
The transition from markov state "3 => lost packets within a burst period" to "1 => successfully transmitted packets within a gap period" has no *additional* loss event. The loss already happen for transition from 1 -> 3, this additional loss will make things go wild. E.g. transition probabilities: p13: 10% p31: 100% Expected: Ploss = p13 / (p13 + p31) Ploss = ~9.09% ... but it isn't. Even worse: we get a double loss - each time. So simple don't return true to indicate loss, rather break and return false. Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Stefano Salsano <stefano.salsano@uniroma2.it> Cc: Fabio Ludovici <fabio.ludovici@yahoo.it> Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-11netem: free skb's in tree on resetstephen hemminger
Netem can leak memory because packets get stored in red-black tree and it is not cleared on reset. Reported by: Сергеев Сергей <adron@yapic.net> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-10-11netem: update backlog after dropstephen hemminger
When packet is dropped from rb-tree netem the backlog statistic should also be updated. Reported-by: Сергеев Сергей <adron@yapic.net> Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-31netem: Introduce skb_orphan_partial() helperEric Dumazet
Commit 547669d483e578 ("tcp: xps: fix reordering issues") added unexpected reorders in case netem is used in a MQ setup for high performance test bed. ETH=eth0 tc qd del dev $ETH root 2>/dev/null tc qd add dev $ETH root handle 1: mq for i in `seq 1 32` do tc qd add dev $ETH parent 1:$i netem delay 100ms done As all tcp packets are orphaned by netem, TCP stack believes it can set skb->ooo_okay on all packets. In order to allow producers to send more packets, we want to keep sk_wmem_alloc from reaching sk_sndbuf limit. We can do that by accounting one byte per skb in netem queues, so that TCP stack is not fooled too much. Tested: With above MQ/netem setup, scaling number of concurrent flows gives linear results and no reorders/retransmits lpq83:~# for n in 1 10 20 30 40 50 60 70 80 90 100 do echo -n "n:$n " ; ./super_netperf $n -H 10.7.7.84; done n:1 198.46 n:10 2002.69 n:20 4000.98 n:30 6006.35 n:40 8020.93 n:50 10032.3 n:60 12081.9 n:70 13971.3 n:80 16009.7 n:90 17117.3 n:100 17425.5 Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-03netem: fix possible NULL deref in netem_dequeue()Eric Dumazet
commit aec0a40a6f7884 ("netem: use rb tree to implement the time queue") added a regression if a child qdisc is attached to netem, as we perform a NULL dereference. Fix this by adding a temporary variable to cache netem_skb_cb(skb)->time_to_send. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-07-01netem: use rb tree to implement the time queueEric Dumazet
Following typical setup to implement a ~100 ms RTT and big amount of reorders has very poor performance because netem implements the time queue using a linked list. ----------------------------------------------------------- ETH=eth0 IFB=ifb0 modprobe ifb ip link set dev $IFB up tc qdisc add dev $ETH ingress 2>/dev/null tc filter add dev $ETH parent ffff: \ protocol ip u32 match u32 0 0 flowid 1:1 action mirred egress \ redirect dev $IFB ethtool -K $ETH gro off tso off gso off tc qdisc add dev $IFB root netem delay 50ms 10ms limit 100000 tc qd add dev $ETH root netem delay 50ms limit 100000 --------------------------------------------------------- Switch netem time queue to a rb tree, so this kind of setup can work at high speed. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-01-29netem: fix delay calculation in rate extensionJohannes Naab
The delay calculation with the rate extension introduces in v3.3 does not properly work, if other packets are still queued for transmission. For the delay calculation to work, both delay types (latency and delay introduces by rate limitation) have to be handled differently. The latency delay for a packet can overlap with the delay of other packets. The delay introduced by the rate however is separate, and can only start, once all other rate-introduced delays finished. Latency delay is from same distribution for each packet, rate delay depends on the packet size. .: latency delay -: rate delay x: additional delay we have to wait since another packet is currently transmitted .....---- Packet 1 .....xx------ Packet 2 .....------ Packet 3 ^^^^^ latency stacks ^^ rate delay doesn't stack ^^ latency stacks -----> time When a packet is enqueued, we first consider the latency delay. If other packets are already queued, we can reduce the latency delay until the last packet in the queue is send, however the latency delay cannot be <0, since this would mean that the rate is overcommitted. The new reference point is the time at which the last packet will be send. To find the time, when the packet should be send, the rate introduces delay has to be added on top of that. Signed-off-by: Johannes Naab <jn@stusta.de> Acked-by: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-16netem: refine early skb orphaningEric Dumazet
netem does an early orphaning of skbs. Doing so breaks TCP Small Queue or any mechanism relying on socket sk_wmem_alloc feedback. Ideally, we should perform this orphaning after the rate module and before the delay module, to mimic what happens on a real link : skb orphaning is indeed normally done at TX completion, before the transit on the link. +-------+ +--------+ +---------------+ +-----------------+ + Qdisc +---> Device +--> TX completion +--> links / hops +-> + + + xmit + + skb orphaning + + propagation + +-------+ +--------+ +---------------+ +-----------------+ < rate limiting > < delay, drops, reorders > If netem is used without delay feature (drops, reorders, rate limiting), then we should avoid early skb orphaning, to keep pressure on sockets as long as packets are still in qdisc queue. Ideally, netem should be refactored to implement delay module as the last stage. Current algorithm merges the two phases (rate limiting + delay) so its not correct. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Cc: Mark Gordon <msg@google.com> Cc: Andreas Terzis <aterzis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-07-09netem: add limitation to reordered packetsEric Dumazet
Fix two netem bugs : 1) When a frame was dropped by tfifo_enqueue(), drop counter was incremented twice. 2) When reordering is triggered, we enqueue a packet without checking queue limit. This can OOM pretty fast when this is repeated enough, since skbs are orphaned, no socket limit can help in this situation. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Mark Gordon <msg@google.com> Cc: Andreas Terzis <aterzis@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2012-05-07Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller
Conflicts: drivers/net/ethernet/intel/e1000e/param.c drivers/net/wireless/iwlwifi/iwl-agn-rx.c drivers/net/wireless/iwlwifi/iwl-trans-pcie-rx.c drivers/net/wireless/iwlwifi/iwl-trans.h Resolved the iwlwifi conflict with mainline using 3-way diff posted by John Linville and Stephen Rothwell. In 'net' we added a bug fix to make iwlwifi report a more accurate skb->truesize but this conflicted with RX path changes that happened meanwhile in net-next. In e1000e a conflict arose in the validation code for settings of adapter->itr. 'net-next' had more sophisticated logic so that logic was used. Signed-off-by: David S. Miller <davem@davemloft.net>
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