- 06 Sep, 2019 1 commit
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Eric Dumazet authored
Whenever MQ is not used on a multiqueue device, we experience serious reordering problems. Bisection found the cited commit. The issue can be described this way : - A single qdisc hierarchy is shared by all transmit queues. (eg : tc qdisc replace dev eth0 root fq_codel) - When/if try_bulk_dequeue_skb_slow() dequeues a packet targetting a different transmit queue than the one used to build a packet train, we stop building the current list and save the 'bad' skb (P1) in a special queue. (bad_txq) - When dequeue_skb() calls qdisc_dequeue_skb_bad_txq() and finds this skb (P1), it checks if the associated transmit queues is still in frozen state. If the queue is still blocked (by BQL or NIC tx ring full), we leave the skb in bad_txq and return NULL. - dequeue_skb() calls q->dequeue() to get another packet (P2) The other packet can target the problematic queue (that we found in frozen state for the bad_txq packet), but another cpu just ran TX completion and made room in the txq that is now ready to accept new packets. - Packet P2 is sent while P1 is still held in bad_txq, P1 might be sent at next round. In practice P2 is the lead of a big packet train (P2,P3,P4 ...) filling the BQL budget and delaying P1 by many packets :/ To solve this problem, we have to block the dequeue process as long as the first packet in bad_txq can not be sent. Reordering issues disappear and no side effects have been seen. Fixes: a53851e2 ("net: sched: explicit locking in gso_cpu fallback") Signed-off-by:
Eric Dumazet <edumazet@google.com> Cc: John Fastabend <john.fastabend@gmail.com> Acked-by:
John Fastabend <john.fastabend@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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- 28 Aug, 2019 2 commits
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Davide Caratti authored
Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we can't assume anymore that per-cpu counters are there in the error path of skb_array_produce(). Otherwise, the following splat can be seen: Unable to handle kernel paging request at virtual address 0000600dea430008 Mem abort info: ESR = 0x96000005 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000005 CM = 0, WnR = 0 user pgtable: 64k pages, 48-bit VAs, pgdp = 000000007b97530e [0000600dea430008] pgd=0000000000000000, pud=0000000000000000 Internal error: Oops: 96000005 [#1] SMP [...] pstate: 10000005 (nzcV daif -PAN -UAO) pc : pfifo_fast_enqueue+0x524/0x6e8 lr : pfifo_fast_enqueue+0x46c/0x6e8 sp : ffff800d39376fe0 x29: ffff800d39376fe0 x28: 1ffff001a07d1e40 x27: ffff800d03e8f188 x26: ffff800d03e8f200 x25: 0000000000000062 x24: ffff800d393772f0 x23: 0000000000000000 x22: 0000000000000403 x21: ffff800cca569a00 x20: ffff800d03e8ee00 x19: ffff800cca569a10 x18: 00000000000000bf x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: ffff1001a726edd0 x13: 1fffe4000276a9a4 x12: 0000000000000000 x11: dfff200000000000 x10: ffff800d03e8f1a0 x9 : 0000000000000003 x8 : 0000000000000000 x7 : 00000000f1f1f1f1 x6 : ffff1001a726edea x5 : ffff800cca56a53c x4 : 1ffff001bf9a8003 x3 : 1ffff001bf9a8003 x2 : 1ffff001a07d1dcb x1 : 0000600dea430000 x0 : 0000600dea430008 Process ping (pid: 6067, stack limit = 0x00000000dc0aa557) Call trace: pfifo_fast_enqueue+0x524/0x6e8 htb_enqueue+0x660/0x10e0 [sch_htb] __dev_queue_xmit+0x123c/0x2de0 dev_queue_xmit+0x24/0x30 ip_finish_output2+0xc48/0x1720 ip_finish_output+0x548/0x9d8 ip_output+0x334/0x788 ip_local_out+0x90/0x138 ip_send_skb+0x44/0x1d0 ip_push_pending_frames+0x5c/0x78 raw_sendmsg+0xed8/0x28d0 inet_sendmsg+0xc4/0x5c0 sock_sendmsg+0xac/0x108 __sys_sendto+0x1ac/0x2a0 __arm64_sys_sendto+0xc4/0x138 el0_svc_handler+0x13c/0x298 el0_svc+0x8/0xc Code: f9402e80 d538d081 91002000 8b010000 (885f7c03) Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_qstats'. Fixes: 8a53e616 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni <pabeni@redhat.com> CC: Stefano Brivio <sbrivio@redhat.com> Reported-by:
Li Shuang <shuali@redhat.com> Signed-off-by:
Davide Caratti <dcaratti@redhat.com> Acked-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
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Davide Caratti authored
Now that 'TCQ_F_CPUSTATS' bit can be cleared, depending on the value of 'TCQ_F_NOLOCK' bit in the parent qdisc, we need to be sure that per-cpu counters are present when 'reset()' is called for pfifo_fast qdiscs. Otherwise, the following script: # tc q a dev lo handle 1: root htb default 100 # tc c a dev lo parent 1: classid 1:100 htb \ > rate 95Mbit ceil 100Mbit burst 64k [...] # tc f a dev lo parent 1: protocol arp basic classid 1:100 [...] # tc q a dev lo parent 1:100 handle 100: pfifo_fast [...] # tc q d dev lo root can generate the following splat: Unable to handle kernel paging request at virtual address dfff2c01bd148000 Mem abort info: ESR = 0x96000004 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 [dfff2c01bd148000] address between user and kernel address ranges Internal error: Oops: 96000004 [#1] SMP [...] pstate: 80000005 (Nzcv daif -PAN -UAO) pc : pfifo_fast_reset+0x280/0x4d8 lr : pfifo_fast_reset+0x21c/0x4d8 sp : ffff800d09676fa0 x29: ffff800d09676fa0 x28: ffff200012ee22e4 x27: dfff200000000000 x26: 0000000000000000 x25: ffff800ca0799958 x24: ffff1001940f332b x23: 0000000000000007 x22: ffff200012ee1ab8 x21: 0000600de8a40000 x20: 0000000000000000 x19: ffff800ca0799900 x18: 0000000000000000 x17: 0000000000000002 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: ffff1001b922e6e2 x11: 1ffff001b922e6e1 x10: 0000000000000000 x9 : 1ffff001b922e6e1 x8 : dfff200000000000 x7 : 0000000000000000 x6 : 0000000000000000 x5 : 1fffe400025dc45c x4 : 1fffe400025dc357 x3 : 00000c01bd148000 x2 : 0000600de8a40000 x1 : 0000000000000007 x0 : 0000600de8a40004 Call trace: pfifo_fast_reset+0x280/0x4d8 qdisc_reset+0x6c/0x370 htb_reset+0x150/0x3b8 [sch_htb] qdisc_reset+0x6c/0x370 dev_deactivate_queue.constprop.5+0xe0/0x1a8 dev_deactivate_many+0xd8/0x908 dev_deactivate+0xe4/0x190 qdisc_graft+0x88c/0xbd0 tc_get_qdisc+0x418/0x8a8 rtnetlink_rcv_msg+0x3a8/0xa78 netlink_rcv_skb+0x18c/0x328 rtnetlink_rcv+0x28/0x38 netlink_unicast+0x3c4/0x538 netlink_sendmsg+0x538/0x9a0 sock_sendmsg+0xac/0xf8 ___sys_sendmsg+0x53c/0x658 __sys_sendmsg+0xc8/0x140 __arm64_sys_sendmsg+0x74/0xa8 el0_svc_handler+0x164/0x468 el0_svc+0x10/0x14 Code: 910012a0 92400801 d343fc03 11000c21 (38fb6863) Fix this by testing the value of 'TCQ_F_CPUSTATS' bit in 'qdisc->flags', before dereferencing 'qdisc->cpu_qstats'. Changes since v1: - coding style improvements, thanks to Stefano Brivio Fixes: 8a53e616 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too") CC: Paolo Abeni <pabeni@redhat.com> Reported-by:
Stefano Brivio <sbrivio@redhat.com> Signed-off-by:
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- 30 May, 2019 1 commit
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Thomas Gleixner authored
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Reviewed-by:
Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 04 May, 2019 1 commit
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Cong Wang authored
Although devlink health report does a nice job on reporting TX timeout and other NIC errors, unfortunately it requires drivers to support it but currently only mlx5 has implemented it. Before other drivers could catch up, it is useful to have a generic tracepoint to monitor this kind of TX timeout. We have been suffering TX timeout with different drivers, we plan to start to monitor it with rasdaemon which just needs a new tracepoint. Sample output: ksoftirqd/1-16 [001] ..s2 144.043173: net_dev_xmit_timeout: dev=ens3 driver=e1000 queue=0 Cc: Eran Ben Elisha <eranbe@mellanox.com> Cc: Jiri Pirko <jiri@mellanox.com> Signed-off-by:
Cong Wang <xiyou.wangcong@gmail.com> Acked-by:
Jiri Pirko <jiri@mellanox.com> Reviewed-by:
Eran Ben Elisha <eranbe@mellanox.com> Signed-off-by:
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- 10 Apr, 2019 3 commits
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Paolo Abeni authored
This revert commit 46b1c18f ("net: sched: put back q.qlen into a single location"). After the previous patch, when a NOLOCK qdisc is enslaved to a locking qdisc it switches to global stats accounting. As a consequence, when a classful qdisc accesses directly a child qdisc's qlen, such qdisc is not doing per CPU accounting and qlen value is consistent. In the control path nobody uses directly qlen since commit e5f0e8f8 ("net: sched: introduce and use qdisc tree flush/purge helpers"), so we can remove the contented atomic ops from the datapath. v1 -> v2: - complete the qdisc_qstats_atomic_qlen_dec() -> qdisc_qstats_cpu_qlen_dec() replacement, fix build issue - more descriptive commit message Signed-off-by:
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Paolo Abeni authored
Since stats updating is always consistent with TCQ_F_CPUSTATS flag, we can disable it at qdisc creation time flipping such bit. In my experiments, if the NOLOCK flag is cleared, per CPU stats accounting does not give any measurable performance gain, but it waste some memory. Let's clear TCQ_F_CPUSTATS together with NOLOCK, when enslaving a NOLOCK qdisc to 'lock' one. Use stats update helper inside pfifo_fast, to cope correctly with TCQ_F_CPUSTATS flag change. As a side effect, q.qlen value for any child qdiscs is always consistent for all lock classfull qdiscs. Signed-off-by:
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Paolo Abeni authored
The core sched implementation checks independently for NOLOCK flag to acquire/release the root spin lock and for qdisc_is_percpu_stats() to account per CPU values in many places. This change update the last few places checking the TCQ_F_NOLOCK to do per CPU stats accounting according to qdisc_is_percpu_stats() value. The above allows to clean dev_requeue_skb() implementation a bit and makes stats update always consistent with a single flag. v1 -> v2: - do not move qdisc_is_empty definition, fix build issue Signed-off-by:
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- 24 Mar, 2019 1 commit
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Paolo Abeni authored
The queue is marked not empty after acquiring the seqlock, and it's up to the NOLOCK qdisc clearing such flag on dequeue. Since the empty status lays on the same cache-line of the seqlock, it's always hot on cache during the updates. This makes the empty flag update a little bit loosy. Given the lack of synchronization between enqueue and dequeue, this is unavoidable. v2 -> v3: - qdisc_is_empty() has a const argument (Eric) v1 -> v2: - use really an 'empty' flag instead of 'not_empty', as suggested by Eric Signed-off-by:
Ivan Vecera <ivecera@redhat.com> Signed-off-by:
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- 02 Mar, 2019 1 commit
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Eric Dumazet authored
In the series fc8b81a5 ("Merge branch 'lockless-qdisc-series'") John made the assumption that the data path had no need to read the qdisc qlen (number of packets in the qdisc). It is true when pfifo_fast is used as the root qdisc, or as direct MQ/MQPRIO children. But pfifo_fast can be used as leaf in class full qdiscs, and existing logic needs to access the child qlen in an efficient way. HTB breaks badly, since it uses cl->leaf.q->q.qlen in : htb_activate() -> WARN_ON() htb_dequeue_tree() to decide if a class can be htb_deactivated when it has no more packets. HFSC, DRR, CBQ, QFQ have similar issues, and some calls to qdisc_tree_reduce_backlog() also read q.qlen directly. Using qdisc_qlen_sum() (which iterates over all possible cpus) in the data path is a non starter. It seems we have to put back qlen in a central location, at least for stable kernels. For all qdisc but pfifo_fast, qlen is guarded by the qdisc lock, so the existing q.qlen{++|--} are correct. For 'lockless' qdisc (pfifo_fast so far), we need to use atomic_{inc|dec}() because the spinlock might be not held (for example from pfifo_fast_enqueue() and pfifo_fast_dequeue()) This patch adds atomic_qlen (in the same location than qlen) and renames the following helpers, since we want to express they can be used without qdisc lock, and that qlen is no longer percpu. - qdisc_qstats_cpu_qlen_dec -> qdisc_qstats_atomic_qlen_dec() - qdisc_qstats_cpu_qlen_inc -> qdisc_qstats_atomic_qlen_inc() Later (net-next) we might revert this patch by tracking all these qlen uses and replace them by a more efficient method (not having to access a precise qlen, but an empty/non_empty status that might be less expensive to maintain/track). Another possibility is to have a legacy pfifo_fast version that would be used when used a a child qdisc, since the parent qdisc needs a spinlock anyway. But then, future lockless qdiscs would also have the same problem. Fixes: 7e66016f ("net: sched: helpers to sum qlen and qlen for per cpu logic") Signed-off-by:
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- 26 Feb, 2019 1 commit
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Li RongQing authored
This pointer is RCU protected, so proper primitives should be used. Signed-off-by:
Zhang Yu <zhangyu31@baidu.com> Signed-off-by:
Li RongQing <lirongqing@baidu.com> Signed-off-by:
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- 12 Feb, 2019 1 commit
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Vlad Buslov authored
Extend tcf_chain with new filter_chain_lock mutex. Always lock the chain when accessing filter_chain list, instead of relying on rtnl lock. Dereference filter_chain with tcf_chain_dereference() lockdep macro to verify that all users of chain_list have the lock taken. Rearrange tp insert/remove code in tc_new_tfilter/tc_del_tfilter to execute all necessary code while holding chain lock in order to prevent invalidation of chain_info structure by potential concurrent change. This also serializes calls to tcf_chain0_head_change(), which allows head change callbacks to rely on filter_chain_lock for synchronization instead of rtnl mutex. Signed-off-by:
Vlad Buslov <vladbu@mellanox.com> Acked-by:
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- 11 Feb, 2019 1 commit
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Jouke Witteveen authored
Netlink has moved from bitmasks to group numbers long ago. Signed-off-by:
Jouke Witteveen <j.witteveen@gmail.com> Signed-off-by:
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- 01 Dec, 2018 1 commit
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Paul E. McKenney authored
Now that call_rcu()'s callback is not invoked until after bh-disable regions of code have completed (in addition to explicitly marked RCU read-side critical sections), call_rcu() can be used in place of call_rcu_bh(). Similarly, rcu_barrier() can be used in place o frcu_barrier_bh(). This commit therefore makes these changes. Signed-off-by:Paul E. McKenney <paulmck@linux.ibm.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jiri Pirko <jiri@resnulli.us> Cc: "David S. Miller" <davem@davemloft.net> Cc: <netdev@vger.kernel.org>
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- 11 Oct, 2018 1 commit
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Eric Dumazet authored
While noop_qdisc.gso_skb and noop_qdisc.skb_bad_txq are not used in other places, it seems not correct to overwrite their fields in dev_init_scheduler_queue(). noop_qdisc is essentially a shared and read-only object, even if it is not marked as const because of some implementation detail. Signed-off-by:
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- 28 Sep, 2018 1 commit
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Wei Yongjun authored
Fixes the following sparse warning: net/sched/sch_generic.c:944:6: warning: symbol 'qdisc_free_cb' was not declared. Should it be static? Fixes: 3a7d0d07 ("net: sched: extend Qdisc with rcu") Signed-off-by:
Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by:
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- 26 Sep, 2018 2 commits
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Vlad Buslov authored
Currently, Qdisc API functions assume that users have rtnl lock taken. To implement rtnl unlocked classifiers update interface, Qdisc API must be extended with functions that do not require rtnl lock. Extend Qdisc structure with rcu. Implement special version of put function qdisc_put_unlocked() that is called without rtnl lock taken. This function only takes rtnl lock if Qdisc reference counter reached zero and is intended to be used as optimization. Signed-off-by:
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Vlad Buslov authored
Current implementation of qdisc_destroy() decrements Qdisc reference counter and only actually destroy Qdisc if reference counter value reached zero. Rename qdisc_destroy() to qdisc_put() in order for it to better describe the way in which this function currently implemented and used. Extract code that deallocates Qdisc into new private qdisc_destroy() function. It is intended to be shared between regular qdisc_put() and its unlocked version that is introduced in next patch in this series. Signed-off-by:
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- 10 Sep, 2018 1 commit
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David S. Miller authored
An SKB is not on a list if skb->next is NULL. Codify this convention into a helper function and use it where we are dequeueing an SKB and need to mark it as such. Signed-off-by:
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- 31 May, 2018 1 commit
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Song Liu authored
Checking netif_xmit_frozen_or_stopped() at the end of sch_direct_xmit() is being bypassed. This is because "ret" from sch_direct_xmit() will be either NETDEV_TX_OK or NETDEV_TX_BUSY, and only ret == NETDEV_TX_OK == 0 will reach the condition: if (ret && netif_xmit_frozen_or_stopped(txq)) return false; This patch cleans up the code by removing the whole condition. For more discussion about this, please refer to https://marc.info/?t=152727195700008 Signed-off-by:Song Liu <songliubraving@fb.com> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: David S. Miller <davem@davemloft.net> Signed-off-by:
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- 17 May, 2018 2 commits
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Paolo Abeni authored
After the previous patch, for NOLOCK qdiscs, q->seqlock is always held when the dequeue() is invoked, we can drop any additional locking to protect such operation. Signed-off-by:
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Paolo Abeni authored
So that we can use lockdep on it. The newly introduced sequence lock has the same scope of busylock, so it shares the same lockdep annotation, but it's only used for NOLOCK qdiscs. With this changeset we acquire such lock in the control path around flushing operation (qdisc reset), to allow more NOLOCK qdisc perf improvement in the next patch. Signed-off-by:
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- 16 May, 2018 1 commit
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Paolo Abeni authored
Currently NOLOCK qdiscs pay a measurable overhead to atomically manipulate the __QDISC_STATE_RUNNING. Such bit is flipped twice per packet in the uncontended scenario with packet rate below the line rate: on packed dequeue and on the next, failing dequeue attempt. This changeset moves the bit manipulation into the qdisc_run_{begin,end} helpers, so that the bit is now flipped only once per packet, with measurable performance improvement in the uncontended scenario. This also allows simplifying the qdisc teardown code path - since qdisc_is_running() is now effective for each qdisc type - and avoid a possible race between qdisc_run() and dev_deactivate_many(), as now the some_qdisc_is_busy() can properly detect NOLOCK qdiscs being busy dequeuing packets. Signed-off-by:
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- 26 Mar, 2018 1 commit
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John Fastabend authored
After the qdisc lock was dropped in pfifo_fast we allow multiple enqueue threads and dequeue threads to run in parallel. On the enqueue side the skb bit ooo_okay is used to ensure all related skbs are enqueued in-order. On the dequeue side though there is no similar logic. What we observe is with fewer queues than CPUs it is possible to re-order packets when two instances of __qdisc_run() are running in parallel. Each thread will dequeue a skb and then whichever thread calls the ndo op first will be sent on the wire. This doesn't typically happen because qdisc_run() is usually triggered by the same core that did the enqueue. However, drivers will trigger __netif_schedule() when queues are transitioning from stopped to awake using the netif_tx_wake_* APIs. When this happens netif_schedule() calls qdisc_run() on the same CPU that did the netif_tx_wake_* which is usually done in the interrupt completion context. This CPU is selected with the irq affinity which is unrelated to the enqueue operations. To resolve this we add a RUNNING bit to the qdisc to ensure only a single dequeue per qdisc is running. Enqueue and dequeue operations can still run in parallel and also on multi queue NICs we can still have a dequeue in-flight per qdisc, which is typically per CPU. Fixes: c5ad119f ("net: sched: pfifo_fast use skb_array") Reported-by:
Jakob Unterwurzacher <jakob.unterwurzacher@theobroma-systems.com> Signed-off-by:
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- 17 Mar, 2018 1 commit
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Eric Dumazet authored
syzbot reported one use-after-free in pfifo_fast_enqueue() [1] Issue here is that we can not reuse skb after a successful skb_array_produce() since another cpu might have consumed it already. I believe a similar problem exists in try_bulk_dequeue_skb_slow() in case we put an skb into qdisc_enqueue_skb_bad_txq() for lockless qdisc. [1] BUG: KASAN: use-after-free in qdisc_pkt_len include/net/sch_generic.h:610 [inline] BUG: KASAN: use-after-free in qdisc_qstats_cpu_backlog_inc include/net/sch_generic.h:712 [inline] BUG: KASAN: use-after-free in pfifo_fast_enqueue+0x4bc/0x5e0 net/sched/sch_generic.c:639 Read of size 4 at addr ffff8801cede37e8 by task syzkaller717588/5543 CPU: 1 PID: 5543 Comm: syzkaller717588 Not tainted 4.16.0-rc4+ #265 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 print_address_description+0x73/0x250 mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report+0x23c/0x360 mm/kasan/report.c:412 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 qdisc_pkt_len include/net/sch_generic.h:610 [inline] qdisc_qstats_cpu_backlog_inc include/net/sch_generic.h:712 [inline] pfifo_fast_enqueue+0x4bc/0x5e0 net/sched/sch_generic.c:639 __dev_xmit_skb net/core/dev.c:3216 [inline] Fixes: c5ad119f ("net: sched: pfifo_fast use skb_array") Signed-off-by:
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- 29 Jan, 2018 2 commits
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Cong Wang authored
pfifo_fast used to drop based on qdisc_dev(qdisc)->tx_queue_len, so we have to resize skb array when we change tx_queue_len. Other qdiscs which read tx_queue_len are fine because they all save it to sch->limit or somewhere else in qdisc during init. They don't have to implement this, it is nicer if they do so that users don't have to re-configure qdisc after changing tx_queue_len. Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by:
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Cong Wang authored
Introduce a new qdisc ops ->change_tx_queue_len() so that each qdisc could decide how to implement this if it wants. Previously we simply read dev->tx_queue_len, after pfifo_fast switches to skb array, we need this API to resize the skb array when we change dev->tx_queue_len. To avoid handling race conditions with TX BH, we need to deactivate all TX queues before change the value and bring them back after we are done, this also makes implementation easier. Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by:
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- 22 Jan, 2018 1 commit
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David Decotigny authored
Expose the number of times the link has been going UP or DOWN, and update the "carrier_changes" counter to be the sum of these two events. While at it, also update the sysfs-class-net documentation to cover: carrier_changes (3.15), carrier_up_count (4.16) and carrier_down_count (4.16) Signed-off-by:
David Decotigny <decot@googlers.com> [Florian: * rebase * add documentation * merge carrier_changes with up/down counters] Signed-off-by:
Florian Fainelli <f.fainelli@gmail.com> Signed-off-by:
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- 16 Jan, 2018 1 commit
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Daniel Borkmann authored
While working on fixing another bug, I ran into the following panic on arm64 by simply attaching clsact qdisc, adding a filter and running traffic on ingress to it: [...] [ 178.188591] Unable to handle kernel read from unreadable memory at virtual address 810fb501f000 [ 178.197314] Mem abort info: [ 178.200121] ESR = 0x96000004 [ 178.203168] Exception class = DABT (current EL), IL = 32 bits [ 178.209095] SET = 0, FnV = 0 [ 178.212157] EA = 0, S1PTW = 0 [ 178.215288] Data abort info: [ 178.218175] ISV = 0, ISS = 0x00000004 [ 178.222019] CM = 0, WnR = 0 [ 178.224997] user pgtable: 4k pages, 48-bit VAs, pgd = 0000000023cb3f33 [ 178.231531] [0000810fb501f000] *pgd=0000000000000000 [ 178.236508] Internal error: Oops: 96000004 [#1] SMP [...] [ 178.311855] CPU: 73 PID: 2497 Comm: ping Tainted: G W 4.15.0-rc7+ #5 [ 178.319413] Hardware name: FOXCONN R2-1221R-A4/C2U4N_MB, BIOS G31FB18A 03/31/2017 [ 178.326887] pstate: 60400005 (nZCv daif +PAN -UAO) [ 178.331685] pc : __netif_receive_skb_core+0x49c/0xac8 [ 178.336728] lr : __netif_receive_skb+0x28/0x78 [ 178.341161] sp : ffff00002344b750 [ 178.344465] x29: ffff00002344b750 x28: ffff810fbdfd0580 [ 178.349769] x27: 0000000000000000 x26: ffff000009378000 [...] [ 178.418715] x1 : 0000000000000054 x0 : 0000000000000000 [ 178.424020] Process ping (pid: 2497, stack limit = 0x000000009f0a3ff4) [ 178.430537] Call trace: [ 178.432976] __netif_receive_skb_core+0x49c/0xac8 [ 178.437670] __netif_receive_skb+0x28/0x78 [ 178.441757] process_backlog+0x9c/0x160 [ 178.445584] net_rx_action+0x2f8/0x3f0 [...] Reason is that sch_ingress and sch_clsact are doing mini_qdisc_pair_init() which sets up miniq pointers to cpu_{b,q}stats from the underlying qdisc. Problem is that this cannot work since they are actually set up right after the qdisc ->init() callback in qdisc_create(), so first packet going into sch_handle_ingress() tries to call mini_qdisc_bstats_cpu_update() and we therefore panic. In order to fix this, allocation of {b,q}stats needs to happen before we call into ->init(). In net-next, there's already such option through commit d59f5ffa ("net: sched: a dflt qdisc may be used with per cpu stats"). However, the bug needs to be fixed in net still for 4.15. Thus, include these bits to reduce any merge churn and reuse the static_flags field to set TCQ_F_CPUSTATS, and remove the allocation from qdisc_create() since there is no other user left. Prashant Bhole ran into the same issue but for net-next, thus adding him below as well as co-author. Same issue was also reported by Sandipan Das when using bcc. Fixes: 46209401 ("net: core: introduce mini_Qdisc and eliminate usage of tp->q for clsact fastpath") Reference: https://lists.iovisor.org/pipermail/iovisor-dev/2018-January/001190.html Reported-by:Sandipan Das <sandipan@linux.vnet.ibm.com> Co-authored-by:
Prashant Bhole <bhole_prashant_q7@lab.ntt.co.jp> Co-authored-by:
Daniel Borkmann <daniel@iogearbox.net> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by:
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- 02 Jan, 2018 1 commit
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Wei Yongjun authored
When dev_requeue_skb() is called with bulked skb list, only the first skb of the list will be requeued to qdisc layer, and leak the others without free them. TCP is broken due to skb leak since no free skb will be considered as still in the host queue and never be retransmitted. This happend when dev_requeue_skb() called from qdisc_restart(). qdisc_restart |-- dequeue_skb |-- sch_direct_xmit() |-- dev_requeue_skb() <-- skb may bluked Fix dev_requeue_skb() to requeue the full bluked list. Also change to use __skb_queue_tail() in __dev_requeue_skb() to avoid skb out of order. Fixes: a53851e2 ("net: sched: explicit locking in gso_cpu fallback") Signed-off-by:
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- 26 Dec, 2017 1 commit
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Cong Wang authored
The rcu_barrier_bh() in mini_qdisc_pair_swap() is to wait for flying RCU callback installed by a previous mini_qdisc_pair_swap(), however we miss it on the tp_head==NULL path, which leads to that the RCU callback still uses miniq_old->rcu after it is freed together with qdisc in qdisc_graft(). So just add it on that path too. Fixes: 46209401 ("net: core: introduce mini_Qdisc and eliminate usage of tp->q for clsact fastpath ") Reported-by:
Jakub Kicinski <jakub.kicinski@netronome.com> Tested-by:
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- 21 Dec, 2017 3 commits
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Alexander Aring authored
This patch adds extack support for the function qdisc_create_dflt which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_create_dflt failed. The function qdisc_create_dflt will also call an init callback which can fail by any per-qdisc specific handling. Cc: David Ahern <dsahern@gmail.com> Acked-by:
Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by:
Alexander Aring <aring@mojatatu.com> Signed-off-by:
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Alexander Aring authored
This patch adds extack support for the function qdisc_alloc which is a common used function in the tc subsystem. Callers which are interested in the receiving error can assign extack to get a more detailed information why qdisc_alloc failed. Cc: David Ahern <dsahern@gmail.com> Acked-by:
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Alexander Aring authored
This patch adds extack support for init callback to prepare per-qdisc specific changes for extack. Cc: David Ahern <dsahern@gmail.com> Acked-by:
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- 20 Dec, 2017 1 commit
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Steffen Klassert authored
This patch implements asynchronous crypto callbacks and a backlog handler that can be used when IPsec is done at layer 2 in the TX path. It also extends the skb validate functions so that we can update the driver transmit return codes based on async crypto operation or to indicate that we queued the packet in a backlog queue. Joint work with: Aviv Heller <avivh@mellanox.com> Signed-off-by:Steffen Klassert <steffen.klassert@secunet.com>
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- 19 Dec, 2017 1 commit
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Cong Wang authored
First, the check of &q->ring.queue against NULL is wrong, it is always false. We should check the value rather than the address. Secondly, we need the same check in pfifo_fast_reset() too, as both ->reset() and ->destroy() are called in qdisc_destroy(). Fixes: c5ad119f ("net: sched: pfifo_fast use skb_array") Reported-by:
syzbot <syzkaller@googlegroups.com> Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by:
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- 08 Dec, 2017 4 commits
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John Fastabend authored
This converts the pfifo_fast qdisc to use the skb_array data structure and set the lockless qdisc bit. pfifo_fast is the first qdisc to support the lockless bit that can be a child of a qdisc requiring locking. So we add logic to clear the lock bit on initialization in these cases when the qdisc graft operation occurs. This also removes the logic used to pick the next band to dequeue from and instead just checks a per priority array for packets from top priority to lowest. This might need to be a bit more clever but seems to work for now. Signed-off-by:
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John Fastabend authored
I can not think of any reason to pull the bad txq skb off the qdisc if the txq we plan to send this on is still frozen. So check for frozen queue first and abort before dequeuing either skb_bad_txq skb or normal qdisc dequeue() skb. Signed-off-by:
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John Fastabend authored
Similar to how gso is handled use skb list for skb_bad_tx this is required with lockless qdiscs because we may have multiple cores attempting to push skbs into skb_bad_tx concurrently Signed-off-by:
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John Fastabend authored
In qdisc_graft_qdisc a "new" qdisc is attached and the 'qdisc_destroy' operation is called on the old qdisc. The destroy operation will wait a rcu grace period and call qdisc_rcu_free(). At which point gso_cpu_skb is free'd along with all stats so no need to zero stats and gso_cpu_skb from the graft operation itself. Further after dropping the qdisc locks we can not continue to call qdisc_reset before waiting an rcu grace period so that the qdisc is detached from all cpus. By removing the qdisc_reset() here we get the correct property of waiting an rcu grace period and letting the qdisc_destroy operation clean up the qdisc correctly. Note, a refcnt greater than 1 would cause the destroy operation to be aborted however if this ever happened the reference to the qdisc would be lost and we would have a memory leak. Signed-off-by:
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