linux.git/net/sched, branch v5.3.2

net_sched: let qdisc_put() accept NULL pointer

2019-09-21T05:19:38+00:00

[ Upstream commit 6efb971ba8edfbd80b666f29de12882852f095ae ]

When tcf_block_get() fails in sfb_init(), q->qdisc is still a NULL
pointer which leads to a crash in sfb_destroy(). Similar for
sch_dsmark.

Instead of fixing each separately, Linus suggested to just accept
NULL pointer in qdisc_put(), which would make callers easier.

(For sch_dsmark, the bug probably exists long before commit
6529eaba33f0.)

Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
Reported-by: syzbot+d5870a903591faaca4ae@syzkaller.appspotmail.com
Suggested-by: Linus Torvalds 
Cc: Jamal Hadi Salim 
Cc: Jiri Pirko 
Signed-off-by: Cong Wang 
Acked-by: Jiri Pirko 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

sch_hhf: ensure quantum and hhf_non_hh_weight are non-zero

2019-09-10T17:31:00+00:00

In case of TCA_HHF_NON_HH_WEIGHT or TCA_HHF_QUANTUM is zero,
it would make no progress inside the loop in hhf_dequeue() thus
kernel would get stuck.

Fix this by checking this corner case in hhf_change().

Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Reported-by: syzbot+bc6297c11f19ee807dc2@syzkaller.appspotmail.com
Reported-by: syzbot+041483004a7f45f1f20a@syzkaller.appspotmail.com
Reported-by: syzbot+55be5f513bed37fc4367@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim 
Cc: Jiri Pirko 
Cc: Terry Lam 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

net_sched: check cops->tcf_block in tc_bind_tclass()

2019-09-10T17:28:56+00:00

At least sch_red and sch_tbf don't implement ->tcf_block()
while still have a non-zero tc "class".

Instead of adding nop implementations to each of such qdisc's,
we can just relax the check of cops->tcf_block() in
tc_bind_tclass(). They don't support TC filter anyway.

Reported-by: syzbot+21b29db13c065852f64b@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim 
Cc: Jiri Pirko 
Signed-off-by: Cong Wang 
Signed-off-by: David S. Miller

net: sched: fix reordering issues

2019-09-06T13:12:33+00:00

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: a53851e2c321 ("net: sched: explicit locking in gso_cpu fallback")
Signed-off-by: Eric Dumazet 
Cc: John Fastabend 
Acked-by: John Fastabend 
Signed-off-by: David S. Miller

net/sched: cbs: Set default link speed to 10 Mbps in cbs_set_port_rate

2019-09-01T01:45:35+00:00

The discussion to be made is absolutely the same as in the case of
previous patch ("taprio: Set default link speed to 10 Mbps in
taprio_set_picos_per_byte"). Nothing is lost when setting a default.

Cc: Leandro Dorileo 
Fixes: e0a7683d30e9 ("net/sched: cbs: fix port_rate miscalculation")
Acked-by: Vinicius Costa Gomes 
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller

taprio: Set default link speed to 10 Mbps in taprio_set_picos_per_byte

2019-09-01T01:45:34+00:00

The taprio budget needs to be adapted at runtime according to interface
link speed. But that handling is problematic.

For one thing, installing a qdisc on an interface that doesn't have
carrier is not illegal. But taprio prints the following stack trace:

[   31.851373] ------------[ cut here ]------------
[   31.856024] WARNING: CPU: 1 PID: 207 at net/sched/sch_taprio.c:481 taprio_dequeue+0x1a8/0x2d4
[   31.864566] taprio: dequeue() called with unknown picos per byte.
[   31.864570] Modules linked in:
[   31.873701] CPU: 1 PID: 207 Comm: tc Not tainted 5.3.0-rc5-01199-g8838fe023cd6 #1689
[   31.881398] Hardware name: Freescale LS1021A
[   31.885661] [] (unwind_backtrace) from [] (show_stack+0x10/0x14)
[   31.893368] [] (show_stack) from [] (dump_stack+0xb4/0xc8)
[   31.900555] [] (dump_stack) from [] (__warn+0xe0/0xf8)
[   31.907395] [] (__warn) from [] (warn_slowpath_fmt+0x48/0x6c)
[   31.914841] [] (warn_slowpath_fmt) from [] (taprio_dequeue+0x1a8/0x2d4)
[   31.923150] [] (taprio_dequeue) from [] (__qdisc_run+0x90/0x61c)
[   31.930856] [] (__qdisc_run) from [] (net_tx_action+0x12c/0x2bc)
[   31.938560] [] (net_tx_action) from [] (__do_softirq+0x130/0x3c8)
[   31.946350] [] (__do_softirq) from [] (irq_exit+0xbc/0xd8)
[   31.953536] [] (irq_exit) from [] (__handle_domain_irq+0x60/0xb4)
[   31.961328] [] (__handle_domain_irq) from [] (gic_handle_irq+0x58/0x9c)
[   31.969638] [] (gic_handle_irq) from [] (__irq_svc+0x6c/0x90)
[   31.977076] Exception stack(0xe8167b20 to 0xe8167b68)
[   31.982100] 7b20: e9d4bd80 00000cc0 000000cf 00000000 e9d4bd80 c1f38958 00000cc0 c1f38960
[   31.990234] 7b40: 00000001 000000cf 00000004 e9dc0800 00000000 e8167b70 c0f478ec c0f46d94
[   31.998363] 7b60: 60070013 ffffffff
[   32.001833] [] (__irq_svc) from [] (netlink_trim+0x18/0xd8)
[   32.009104] [] (netlink_trim) from [] (netlink_broadcast_filtered+0x34/0x414)
[   32.017930] [] (netlink_broadcast_filtered) from [] (netlink_broadcast+0x20/0x28)
[   32.027102] [] (netlink_broadcast) from [] (rtnetlink_send+0x34/0x88)
[   32.035238] [] (rtnetlink_send) from [] (notify_and_destroy+0x2c/0x44)
[   32.043461] [] (notify_and_destroy) from [] (qdisc_graft+0x398/0x470)
[   32.051595] [] (qdisc_graft) from [] (tc_modify_qdisc+0x3a4/0x724)
[   32.059470] [] (tc_modify_qdisc) from [] (rtnetlink_rcv_msg+0x260/0x2ec)
[   32.067864] [] (rtnetlink_rcv_msg) from [] (netlink_rcv_skb+0xb8/0x110)
[   32.076172] [] (netlink_rcv_skb) from [] (netlink_unicast+0x1b4/0x22c)
[   32.084392] [] (netlink_unicast) from [] (netlink_sendmsg+0x33c/0x380)
[   32.092614] [] (netlink_sendmsg) from [] (sock_sendmsg+0x14/0x24)
[   32.100403] [] (sock_sendmsg) from [] (___sys_sendmsg+0x214/0x228)
[   32.108279] [] (___sys_sendmsg) from [] (__sys_sendmsg+0x50/0x8c)
[   32.116068] [] (__sys_sendmsg) from [] (ret_fast_syscall+0x0/0x54)
[   32.123938] Exception stack(0xe8167fa8 to 0xe8167ff0)
[   32.128960] 7fa0:                   b6fa68c8 000000f8 00000003 bea142d0 00000000 00000000
[   32.137093] 7fc0: b6fa68c8 000000f8 0052154c 00000128 5d6468a2 00000000 00000028 00558c9c
[   32.145224] 7fe0: 00000070 bea14278 00530d64 b6e17e64
[   32.150659] ---[ end trace 2139c9827c3e5177 ]---

This happens because the qdisc ->dequeue callback gets called. Which
again is not illegal, the qdisc will dequeue even when the interface is
up but doesn't have carrier (and hence SPEED_UNKNOWN), and the frames
will be dropped further down the stack in dev_direct_xmit().

And, at the end of the day, for what? For calculating the initial budget
of an interface which is non-operational at the moment and where frames
will get dropped anyway.

So if we can't figure out the link speed, default to SPEED_10 and move
along. We can also remove the runtime check now.

Cc: Leandro Dorileo 
Fixes: 7b9eba7ba0c1 ("net/sched: taprio: fix picos_per_byte miscalculation")
Acked-by: Vinicius Costa Gomes 
Signed-off-by: Vladimir Oltean 
Signed-off-by: David S. Miller

taprio: Fix kernel panic in taprio_destroy

2019-09-01T01:45:34+00:00

taprio_init may fail earlier than this line:

	list_add(&q->taprio_list, &taprio_list);

i.e. due to the net device not being multi queue.

Attempting to remove q from the global taprio_list when it is not part
of it will result in a kernel panic.

Fix it by matching list_add and list_del better to one another in the
order of operations. This way we can keep the deletion unconditional
and with lower complexity - O(1).

Cc: Leandro Dorileo 
Fixes: 7b9eba7ba0c1 ("net/sched: taprio: fix picos_per_byte miscalculation")
Signed-off-by: Vladimir Oltean 
Acked-by: Vinicius Costa Gomes 
Signed-off-by: David S. Miller

net/sched: pfifo_fast: fix wrong dereference in pfifo_fast_enqueue

2019-08-28T22:57:38+00:00

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: 8a53e616de29 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too")
CC: Paolo Abeni 
CC: Stefano Brivio 
Reported-by: Li Shuang 
Signed-off-by: Davide Caratti 
Acked-by: Paolo Abeni 
Signed-off-by: David S. Miller

net: sched: act_sample: fix psample group handling on overwrite

2019-08-28T22:53:51+00:00

Action sample doesn't properly handle psample_group pointer in overwrite
case. Following issues need to be fixed:

- In tcf_sample_init() function RCU_INIT_POINTER() is used to set
  s->psample_group, even though we neither setting the pointer to NULL, nor
  preventing concurrent readers from accessing the pointer in some way.
  Use rcu_swap_protected() instead to safely reset the pointer.

- Old value of s->psample_group is not released or deallocated in any way,
  which results resource leak. Use psample_group_put() on non-NULL value
  obtained with rcu_swap_protected().

- The function psample_group_put() that released reference to struct
  psample_group pointed by rcu-pointer s->psample_group doesn't respect rcu
  grace period when deallocating it. Extend struct psample_group with rcu
  head and use kfree_rcu when freeing it.

Fixes: 5c5670fae430 ("net/sched: Introduce sample tc action")
Signed-off-by: Vlad Buslov 
Signed-off-by: David S. Miller

net/sched: pfifo_fast: fix wrong dereference when qdisc is reset

2019-08-28T21:45:46+00:00

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: 8a53e616de29 ("net: sched: when clearing NOLOCK, clear TCQ_F_CPUSTATS, too")
CC: Paolo Abeni 
Reported-by: Li Shuang 
Signed-off-by: Davide Caratti 
Acked-by: Paolo Abeni 
Reviewed-by: Stefano Brivio 
Signed-off-by: David S. Miller