Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Defer the tcf_exts_destroy() in RCU callback to
tc filter workqueue and get RTNL lock.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch introduces a dedicated workqueue for tc filters
so that each tc filter's RCU callback could defer their
action destroy work to this workqueue. The helper
tcf_queue_work() is introduced for them to use.

Because we hold RTNL lock when calling tcf_block_put(), we
can not simply flush works inside it, therefore we have to
defer it again to this workqueue and make sure all flying RCU
callbacks have already queued their work before this one, in
other words, to ensure this is the last one to execute to
prevent any use-after-free.

On the other hand, this makes tcf_block_put() ugly and
harder to understand. Since David and Eric strongly dislike
adding synchronize_rcu(), this is probably the only
solution that could make everyone happy.

Please also see the code comments below.
Reported-by: NChris Mi <chrism@mellanox.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Davide found the following script triggers a NULL pointer
dereference:

ip l a name eth0 type dummy
tc q a dev eth0 parent :1 handle 1: htb

This is because for a freshly created netdevice noop_qdisc
is attached and when passing 'parent :1', kernel actually
tries to match the major handle which is 0 and noop_qdisc
has handle 0 so is matched by mistake. Commit 69012ae4
tries to fix a similar bug but still misses this case.

Handle 0 is not a valid one, should be just skipped. In
fact, kernel uses it as TC_H_UNSPEC.

Fixes: 69012ae4 ("net: sched: fix handling of singleton qdiscs with qdisc_hash")
Fixes: 59cc1f61 ("net: sched:convert qdisc linked list to hashtable")
Reported-by: NDavide Caratti <dcaratti@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Commit 7091d8c7 '(net/sched: cls_flower: Add offload support using egress
Hardware device') made sure (when fl_hw_replace_filter is called) to put
the egress_dev mark on persisent structure instance. Hence, following calls
into the HW driver for stats and deletion will note it and act accordingly.

With commit de4784ca this property is lost and hence when called,
the HW driver failes to operate (stats, delete) on the offloaded flow.

Fix it by setting the egress_dev flag whenever the ingress device is
different from the hw device since this is exactly the condition under
which we're calling into the HW driver through the egress port net-device.

Fixes: de4784ca ('net: sched: get rid of struct tc_to_netdev')
Signed-off-by: NOr Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: NRoi Dayan <roid@mellanox.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes: c15ab236 ("net/sched: Change cls_flower to use IDR")
Cc: Chris Mi <chrism@mellanox.com>
Cc: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If real-time or fair-share curves are enabled in hfsc_change_class()
class isn't inserted into rb-trees yet. Thus init_ed() and init_vf()
must be called in place of update_ed() and update_vf().

Remove isn't required because for now curves cannot be disabled.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

SKB stored in qdisc->gso_skb also counted into backlog.

Some qdiscs don't reset backlog to zero in ->reset(),
for example sfq just dequeue and free all queued skb.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 2ccccf5f ("net_sched: update hierarchical backlog too")
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

this script, edited from Linux Advanced Routing and Traffic Control guide

tc q a dev en0 root handle 1: htb default a
tc c a dev en0 parent 1:  classid 1:1 htb rate 6mbit burst 15k
tc c a dev en0 parent 1:1 classid 1:a htb rate 5mbit ceil 6mbit burst 15k
tc c a dev en0 parent 1:1 classid 1:b htb rate 1mbit ceil 6mbit burst 15k
tc f a dev en0 parent 1:0 prio 1 $clsname $clsargs classid 1:b
ping $address -c1
tc -s c s dev en0

classifies traffic to 1:b or 1:a, depending on whether the packet matches
or not the pattern $clsargs of filter $clsname. However, when $clsname is
'matchall', a systematic crash can be observed in htb_classify(). HTB and
classful qdiscs don't assign initial value to struct tcf_result, but then
they expect it to contain valid values after filters have been run. Thus,
current 'matchall' ignores the TCA_MATCHALL_CLASSID attribute, configured
by user, and makes HTB (and classful qdiscs) dereference random pointers.

By assigning head->res to *res in mall_classify(), before the actions are
invoked, we fix this crash and enable TCA_MATCHALL_CLASSID functionality,
that had no effect on 'matchall' classifier since its first introduction.

BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1460213Reported-by: NJiri Benc <jbenc@redhat.com>
Fixes: b87f7936 ("net/sched: introduce Match-all classifier")
Signed-off-by: NDavide Caratti <dcaratti@redhat.com>
Acked-by: NYotam Gigi <yotamg@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Recent commit d7fb60b9 ("net_sched: get rid of tcfa_rcu") removed
freeing in call_rcu, which changed already existing hard-to-hit
race condition into 100% hit:

[  598.599825] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
[  598.607782] IP: tcf_action_destroy+0xc0/0x140

Or:

[   40.858924] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
[   40.862840] IP: tcf_generic_walker+0x534/0x820

Fix this by storing the ops and use them directly for module_put call.

Fixes: a85a970a ("net_sched: move tc_action into tcf_common")
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As pointed out by Jiri, there is still a race condition between
tcf_block_put() and tcf_chain_destroy() in a RCU callback. There
is no way to make it correct without proper locking or synchronization,
because both operate on a shared list.

Locking is hard, because the only lock we can pick here is a spinlock,
however, in tc_dump_tfilter() we iterate this list with a sleeping
function called (tcf_chain_dump()), which makes using a lock to protect
chain_list almost impossible.

Jiri suggested the idea of holding a refcnt before flushing, this works
because it guarantees us there would be no parallel tcf_chain_destroy()
during the loop, therefore the race condition is gone. But we have to
be very careful with proper synchronization with RCU callbacks.
Suggested-by: NJiri Pirko <jiri@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch fixes the following ugliness of tc filter chain refcnt:

a) tp proto should hold a refcnt to the chain too. This significantly
   simplifies the logic.

b) Chain 0 is no longer special, it is created with refcnt=1 like any
   other chains. All the ugliness in tcf_chain_put() can be gone!

c) No need to handle the flushing oddly, because block still holds
   chain 0, it can not be released, this guarantees block is the last
   user.

d) The race condition with RCU callbacks is easier to handle with just
   a rcu_barrier(). Much easier to understand, nothing to hide. Thanks
   to the previous patch. Please see also the comments in code.

e) Make the code understandable by humans, much less error-prone.

Fixes: 744a4cf6 ("net: sched: fix use after free when tcf_chain_destroy is called multiple times")
Fixes: 5bc17018 ("net: sched: introduce multichain support for filters")
Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

gen estimator has been rewritten in commit 1c0d32fd
("net_sched: gen_estimator: complete rewrite of rate estimators"),
the caller is no longer needed to wait for a grace period.
So this patch gets rid of it.

This also completely closes a race condition between action free
path and filter chain add/remove path for the following patch.
Because otherwise the nested RCU callback can't be caught by
rcu_barrier().

Please see also the comments in code.

Cc: Jiri Pirko <jiri@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fixes sparse warning about pointer in gen_handle:
net/sched/cls_rsvp.h:392:40: warning: Using plain integer as NULL pointer

Fixes: 8113c095 ("net_sched: use void pointer for filter handle")
Signed-off-by: NJosh Hunt <johunt@akamai.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There's a memleak happening for chain 0. The thing is, chain 0 needs to
be always present, not created on demand. Therefore tcf_block_get upon
creation of block calls the tcf_chain_create function directly. The
chain is created with refcnt == 1, which is not correct in this case and
causes the memleak. So move the refcnt increment into tcf_chain_get
function even for the case when chain needs to be created.
Reported-by: NJakub Kicinski <kubakici@wp.pl>
Fixes: 5bc17018 ("net: sched: introduce multichain support for filters")
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Tested-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 520ac30f ("net_sched: drop packets after root qdisc lock
is released) made a big change of tc for performance. There are two points
left in sch_prio and sch_qfq which are not changed with that commit. Now
enhance them now with __qdisc_drop.
Signed-off-by: NGao Feng <gfree.wind@vip.163.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The new TC IDR code uses GFP_KERNEL under spin lock.  Which leads
to:

[  582.621091] BUG: sleeping function called from invalid context at ../mm/slab.h:416
[  582.629721] in_atomic(): 1, irqs_disabled(): 0, pid: 3379, name: tc
[  582.636939] 2 locks held by tc/3379:
[  582.641049]  #0:  (rtnl_mutex){+.+.+.}, at: [<ffffffff910354ce>] rtnetlink_rcv_msg+0x92e/0x1400
[  582.650958]  #1:  (&(&tn->idrinfo->lock)->rlock){+.-.+.}, at: [<ffffffff9110a5e0>] tcf_idr_create+0x2f0/0x8e0
[  582.662217] Preemption disabled at:
[  582.662222] [<ffffffff9110a5e0>] tcf_idr_create+0x2f0/0x8e0
[  582.672592] CPU: 9 PID: 3379 Comm: tc Tainted: G        W       4.13.0-rc7-debug-00648-g43503a79b9f0 #287
[  582.683432] Hardware name: Dell Inc. PowerEdge R730/072T6D, BIOS 2.3.4 11/08/2016
[  582.691937] Call Trace:
...
[  582.742460]  kmem_cache_alloc+0x286/0x540
[  582.747055]  radix_tree_node_alloc.constprop.6+0x4a/0x450
[  582.753209]  idr_get_free_cmn+0x627/0xf80
...
[  582.815525]  idr_alloc_cmn+0x1a8/0x270
...
[  582.833804]  tcf_idr_create+0x31b/0x8e0
...

Try to preallocate the memory with idr_prealloc(GFP_KERNEL)
(as suggested by Eric Dumazet), and change the allocation
flags under spin lock.

Fixes: 65a206c0 ("net/sched: Change act_api and act_xxx modules to use IDR")
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: NSimon Horman <simon.horman@netronome.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TC filters when used as classifiers are bound to TC classes.
However, there is a hidden difference when adding them in different
orders:

1. If we add tc classes before its filters, everything is fine.
   Logically, the classes exist before we specify their ID's in
   filters, it is easy to bind them together, just as in the current
   code base.

2. If we add tc filters before the tc classes they bind, we have to
   do dynamic lookup in fast path. What's worse, this happens all
   the time not just once, because on fast path tcf_result is passed
   on stack, there is no way to propagate back to the one in tc filters.

This hidden difference hurts performance silently if we have many tc
classes in hierarchy.

This patch intends to close this gap by doing the reverse binding when
we create a new class, in this case we can actually search all the
filters in its parent, match and fixup by classid. And because
tcf_result is specific to each type of tc filter, we have to introduce
a new ops for each filter to tell how to bind the class.

Note, we still can NOT totally get rid of those class lookup in
->enqueue() because cgroup and flow filters have no way to determine
the classid at setup time, they still have to go through dynamic lookup.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sch_tbf calls qdisc_watchdog_cancel() in both its ->reset and ->destroy
callbacks but it may fail before the timer is initialized due to missing
options (either not supplied by user-space or set as a default qdisc),
also q->qdisc is used by ->reset and ->destroy so we need it initialized.

Reproduce:
$ sysctl net.core.default_qdisc=tbf
$ ip l set ethX up

Crash log:
[  959.160172] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
[  959.160323] IP: qdisc_reset+0xa/0x5c
[  959.160400] PGD 59cdb067
[  959.160401] P4D 59cdb067
[  959.160466] PUD 59ccb067
[  959.160532] PMD 0
[  959.160597]
[  959.160706] Oops: 0000 [#1] SMP
[  959.160778] Modules linked in: sch_tbf sch_sfb sch_prio sch_netem
[  959.160891] CPU: 2 PID: 1562 Comm: ip Not tainted 4.13.0-rc6+ #62
[  959.160998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[  959.161157] task: ffff880059c9a700 task.stack: ffff8800376d0000
[  959.161263] RIP: 0010:qdisc_reset+0xa/0x5c
[  959.161347] RSP: 0018:ffff8800376d3610 EFLAGS: 00010286
[  959.161531] RAX: ffffffffa001b1dd RBX: ffff8800373a2800 RCX: 0000000000000000
[  959.161733] RDX: ffffffff8215f160 RSI: ffffffff8215f160 RDI: 0000000000000000
[  959.161939] RBP: ffff8800376d3618 R08: 00000000014080c0 R09: 00000000ffffffff
[  959.162141] R10: ffff8800376d3578 R11: 0000000000000020 R12: ffffffffa001d2c0
[  959.162343] R13: ffff880037538000 R14: 00000000ffffffff R15: 0000000000000001
[  959.162546] FS:  00007fcc5126b740(0000) GS:ffff88005d900000(0000) knlGS:0000000000000000
[  959.162844] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  959.163030] CR2: 0000000000000018 CR3: 000000005abc4000 CR4: 00000000000406e0
[  959.163233] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  959.163436] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  959.163638] Call Trace:
[  959.163788]  tbf_reset+0x19/0x64 [sch_tbf]
[  959.163957]  qdisc_destroy+0x8b/0xe5
[  959.164119]  qdisc_create_dflt+0x86/0x94
[  959.164284]  ? dev_activate+0x129/0x129
[  959.164449]  attach_one_default_qdisc+0x36/0x63
[  959.164623]  netdev_for_each_tx_queue+0x3d/0x48
[  959.164795]  dev_activate+0x4b/0x129
[  959.164957]  __dev_open+0xe7/0x104
[  959.165118]  __dev_change_flags+0xc6/0x15c
[  959.165287]  dev_change_flags+0x25/0x59
[  959.165451]  do_setlink+0x30c/0xb3f
[  959.165613]  ? check_chain_key+0xb0/0xfd
[  959.165782]  rtnl_newlink+0x3a4/0x729
[  959.165947]  ? rtnl_newlink+0x117/0x729
[  959.166121]  ? ns_capable_common+0xd/0xb1
[  959.166288]  ? ns_capable+0x13/0x15
[  959.166450]  rtnetlink_rcv_msg+0x188/0x197
[  959.166617]  ? rcu_read_unlock+0x3e/0x5f
[  959.166783]  ? rtnl_newlink+0x729/0x729
[  959.166948]  netlink_rcv_skb+0x6c/0xce
[  959.167113]  rtnetlink_rcv+0x23/0x2a
[  959.167273]  netlink_unicast+0x103/0x181
[  959.167439]  netlink_sendmsg+0x326/0x337
[  959.167607]  sock_sendmsg_nosec+0x14/0x3f
[  959.167772]  sock_sendmsg+0x29/0x2e
[  959.167932]  ___sys_sendmsg+0x209/0x28b
[  959.168098]  ? do_raw_spin_unlock+0xcd/0xf8
[  959.168267]  ? _raw_spin_unlock+0x27/0x31
[  959.168432]  ? __handle_mm_fault+0x651/0xdb1
[  959.168602]  ? check_chain_key+0xb0/0xfd
[  959.168773]  __sys_sendmsg+0x45/0x63
[  959.168934]  ? __sys_sendmsg+0x45/0x63
[  959.169100]  SyS_sendmsg+0x19/0x1b
[  959.169260]  entry_SYSCALL_64_fastpath+0x23/0xc2
[  959.169432] RIP: 0033:0x7fcc5097e690
[  959.169592] RSP: 002b:00007ffd0d5c7b48 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  959.169887] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007fcc5097e690
[  959.170089] RDX: 0000000000000000 RSI: 00007ffd0d5c7b90 RDI: 0000000000000003
[  959.170292] RBP: ffff8800376d3f98 R08: 0000000000000001 R09: 0000000000000003
[  959.170494] R10: 00007ffd0d5c7910 R11: 0000000000000246 R12: 0000000000000006
[  959.170697] R13: 000000000066f1a0 R14: 00007ffd0d5cfc40 R15: 0000000000000000
[  959.170900]  ? trace_hardirqs_off_caller+0xa7/0xcf
[  959.171076] Code: 00 41 c7 84 24 14 01 00 00 00 00 00 00 41 c7 84 24
98 00 00 00 00 00 00 00 41 5c 41 5d 41 5e 5d c3 66 66 66 66 90 55 48 89
e5 53 <48> 8b 47 18 48 89 fb 48 8b 40 48 48 85 c0 74 02 ff d0 48 8b bb
[  959.171637] RIP: qdisc_reset+0xa/0x5c RSP: ffff8800376d3610
[  959.171821] CR2: 0000000000000018

Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently only a memory allocation failure can lead to this, so let's
initialize the timer first.

Fixes: 6529eaba ("net: sched: introduce tcf block infractructure")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is very unlikely to happen but the backlogs memory allocation
could fail and will free q->flows, but then ->destroy() will free
q->flows too. For correctness remove the first free and let ->destroy
clean up.

Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

CBQ can fail on ->init by wrong nl attributes or simply for missing any,
f.e. if it's set as a default qdisc then TCA_OPTIONS (opt) will be NULL
when it is activated. The first thing init does is parse opt but it will
dereference a null pointer if used as a default qdisc, also since init
failure at default qdisc invokes ->reset() which cancels all timers then
we'll also dereference two more null pointers (timer->base) as they were
never initialized.

To reproduce:
$ sysctl net.core.default_qdisc=cbq
$ ip l set ethX up

Crash log of the first null ptr deref:
[44727.907454] BUG: unable to handle kernel NULL pointer dereference at (null)
[44727.907600] IP: cbq_init+0x27/0x205
[44727.907676] PGD 59ff4067
[44727.907677] P4D 59ff4067
[44727.907742] PUD 59c70067
[44727.907807] PMD 0
[44727.907873]
[44727.907982] Oops: 0000 [#1] SMP
[44727.908054] Modules linked in:
[44727.908126] CPU: 1 PID: 21312 Comm: ip Not tainted 4.13.0-rc6+ #60
[44727.908235] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[44727.908477] task: ffff88005ad42700 task.stack: ffff880037214000
[44727.908672] RIP: 0010:cbq_init+0x27/0x205
[44727.908838] RSP: 0018:ffff8800372175f0 EFLAGS: 00010286
[44727.909018] RAX: ffffffff816c3852 RBX: ffff880058c53800 RCX: 0000000000000000
[44727.909222] RDX: 0000000000000004 RSI: 0000000000000000 RDI: ffff8800372175f8
[44727.909427] RBP: ffff880037217650 R08: ffffffff81b0f380 R09: 0000000000000000
[44727.909631] R10: ffff880037217660 R11: 0000000000000020 R12: ffffffff822a44c0
[44727.909835] R13: ffff880058b92000 R14: 00000000ffffffff R15: 0000000000000001
[44727.910040] FS:  00007ff8bc583740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000
[44727.910339] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[44727.910525] CR2: 0000000000000000 CR3: 00000000371e5000 CR4: 00000000000406e0
[44727.910731] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[44727.910936] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[44727.911141] Call Trace:
[44727.911291]  ? lockdep_init_map+0xb6/0x1ba
[44727.911461]  ? qdisc_alloc+0x14e/0x187
[44727.911626]  qdisc_create_dflt+0x7a/0x94
[44727.911794]  ? dev_activate+0x129/0x129
[44727.911959]  attach_one_default_qdisc+0x36/0x63
[44727.912132]  netdev_for_each_tx_queue+0x3d/0x48
[44727.912305]  dev_activate+0x4b/0x129
[44727.912468]  __dev_open+0xe7/0x104
[44727.912631]  __dev_change_flags+0xc6/0x15c
[44727.912799]  dev_change_flags+0x25/0x59
[44727.912966]  do_setlink+0x30c/0xb3f
[44727.913129]  ? check_chain_key+0xb0/0xfd
[44727.913294]  ? check_chain_key+0xb0/0xfd
[44727.913463]  rtnl_newlink+0x3a4/0x729
[44727.913626]  ? rtnl_newlink+0x117/0x729
[44727.913801]  ? ns_capable_common+0xd/0xb1
[44727.913968]  ? ns_capable+0x13/0x15
[44727.914131]  rtnetlink_rcv_msg+0x188/0x197
[44727.914300]  ? rcu_read_unlock+0x3e/0x5f
[44727.914465]  ? rtnl_newlink+0x729/0x729
[44727.914630]  netlink_rcv_skb+0x6c/0xce
[44727.914796]  rtnetlink_rcv+0x23/0x2a
[44727.914956]  netlink_unicast+0x103/0x181
[44727.915122]  netlink_sendmsg+0x326/0x337
[44727.915291]  sock_sendmsg_nosec+0x14/0x3f
[44727.915459]  sock_sendmsg+0x29/0x2e
[44727.915619]  ___sys_sendmsg+0x209/0x28b
[44727.915784]  ? do_raw_spin_unlock+0xcd/0xf8
[44727.915954]  ? _raw_spin_unlock+0x27/0x31
[44727.916121]  ? __handle_mm_fault+0x651/0xdb1
[44727.916290]  ? check_chain_key+0xb0/0xfd
[44727.916461]  __sys_sendmsg+0x45/0x63
[44727.916626]  ? __sys_sendmsg+0x45/0x63
[44727.916792]  SyS_sendmsg+0x19/0x1b
[44727.916950]  entry_SYSCALL_64_fastpath+0x23/0xc2
[44727.917125] RIP: 0033:0x7ff8bbc96690
[44727.917286] RSP: 002b:00007ffc360991e8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[44727.917579] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007ff8bbc96690
[44727.917783] RDX: 0000000000000000 RSI: 00007ffc36099230 RDI: 0000000000000003
[44727.917987] RBP: ffff880037217f98 R08: 0000000000000001 R09: 0000000000000003
[44727.918190] R10: 00007ffc36098fb0 R11: 0000000000000246 R12: 0000000000000006
[44727.918393] R13: 000000000066f1a0 R14: 00007ffc360a12e0 R15: 0000000000000000
[44727.918597]  ? trace_hardirqs_off_caller+0xa7/0xcf
[44727.918774] Code: 41 5f 5d c3 66 66 66 66 90 55 48 8d 56 04 45 31 c9
49 c7 c0 80 f3 b0 81 48 89 e5 41 55 41 54 53 48 89 fb 48 8d 7d a8 48 83
ec 48 <0f> b7 0e be 07 00 00 00 83 e9 04 e8 e6 f7 d8 ff 85 c0 0f 88 bb
[44727.919332] RIP: cbq_init+0x27/0x205 RSP: ffff8800372175f0
[44727.919516] CR2: 0000000000000000

Fixes: 0fbbeb1b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Depending on where ->init fails we can get a null pointer deref due to
uninitialized hires timer (watchdog) or a double free of the qdisc hash
because it is already freed by ->destroy().

Fixes: 8d553738 ("net/sched/hfsc: allocate tcf block for hfsc root class")
Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If sch_hhf fails in its ->init() function (either due to wrong
user-space arguments as below or memory alloc failure of hh_flows) it
will do a null pointer deref of q->hh_flows in its ->destroy() function.

To reproduce the crash:
$ tc qdisc add dev eth0 root hhf quantum 2000000 non_hh_weight 10000000

Crash log:
[  690.654882] BUG: unable to handle kernel NULL pointer dereference at (null)
[  690.655565] IP: hhf_destroy+0x48/0xbc
[  690.655944] PGD 37345067
[  690.655948] P4D 37345067
[  690.656252] PUD 58402067
[  690.656554] PMD 0
[  690.656857]
[  690.657362] Oops: 0000 [#1] SMP
[  690.657696] Modules linked in:
[  690.658032] CPU: 3 PID: 920 Comm: tc Not tainted 4.13.0-rc6+ #57
[  690.658525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[  690.659255] task: ffff880058578000 task.stack: ffff88005acbc000
[  690.659747] RIP: 0010:hhf_destroy+0x48/0xbc
[  690.660146] RSP: 0018:ffff88005acbf9e0 EFLAGS: 00010246
[  690.660601] RAX: 0000000000000000 RBX: 0000000000000020 RCX: 0000000000000000
[  690.661155] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffff821f63f0
[  690.661710] RBP: ffff88005acbfa08 R08: ffffffff81b10a90 R09: 0000000000000000
[  690.662267] R10: 00000000f42b7019 R11: ffff880058578000 R12: 00000000ffffffea
[  690.662820] R13: ffff8800372f6400 R14: 0000000000000000 R15: 0000000000000000
[  690.663769] FS:  00007f8ae5e8b740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000
[  690.667069] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  690.667965] CR2: 0000000000000000 CR3: 0000000058523000 CR4: 00000000000406e0
[  690.668918] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  690.669945] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  690.671003] Call Trace:
[  690.671743]  qdisc_create+0x377/0x3fd
[  690.672534]  tc_modify_qdisc+0x4d2/0x4fd
[  690.673324]  rtnetlink_rcv_msg+0x188/0x197
[  690.674204]  ? rcu_read_unlock+0x3e/0x5f
[  690.675091]  ? rtnl_newlink+0x729/0x729
[  690.675877]  netlink_rcv_skb+0x6c/0xce
[  690.676648]  rtnetlink_rcv+0x23/0x2a
[  690.677405]  netlink_unicast+0x103/0x181
[  690.678179]  netlink_sendmsg+0x326/0x337
[  690.678958]  sock_sendmsg_nosec+0x14/0x3f
[  690.679743]  sock_sendmsg+0x29/0x2e
[  690.680506]  ___sys_sendmsg+0x209/0x28b
[  690.681283]  ? __handle_mm_fault+0xc7d/0xdb1
[  690.681915]  ? check_chain_key+0xb0/0xfd
[  690.682449]  __sys_sendmsg+0x45/0x63
[  690.682954]  ? __sys_sendmsg+0x45/0x63
[  690.683471]  SyS_sendmsg+0x19/0x1b
[  690.683974]  entry_SYSCALL_64_fastpath+0x23/0xc2
[  690.684516] RIP: 0033:0x7f8ae529d690
[  690.685016] RSP: 002b:00007fff26d2d6b8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  690.685931] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f8ae529d690
[  690.686573] RDX: 0000000000000000 RSI: 00007fff26d2d700 RDI: 0000000000000003
[  690.687047] RBP: ffff88005acbff98 R08: 0000000000000001 R09: 0000000000000000
[  690.687519] R10: 00007fff26d2d480 R11: 0000000000000246 R12: 0000000000000002
[  690.687996] R13: 0000000001258070 R14: 0000000000000001 R15: 0000000000000000
[  690.688475]  ? trace_hardirqs_off_caller+0xa7/0xcf
[  690.688887] Code: 00 00 e8 2a 02 ae ff 49 8b bc 1d 60 02 00 00 48 83
c3 08 e8 19 02 ae ff 48 83 fb 20 75 dc 45 31 f6 4d 89 f7 4d 03 bd 20 02
00 00 <49> 8b 07 49 39 c7 75 24 49 83 c6 10 49 81 fe 00 40 00 00 75 e1
[  690.690200] RIP: hhf_destroy+0x48/0xbc RSP: ffff88005acbf9e0
[  690.690636] CR2: 0000000000000000

Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Fixes: 10239edf ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The below commit added a call to ->destroy() on init failure, but multiq
still frees ->queues on error in init, but ->queues is also freed by
->destroy() thus we get double free and corrupted memory.

Very easy to reproduce (eth0 not multiqueue):
$ tc qdisc add dev eth0 root multiq
RTNETLINK answers: Operation not supported
$ ip l add dumdum type dummy
(crash)

Trace log:
[ 3929.467747] general protection fault: 0000 [#1] SMP
[ 3929.468083] Modules linked in:
[ 3929.468302] CPU: 3 PID: 967 Comm: ip Not tainted 4.13.0-rc6+ #56
[ 3929.468625] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 3929.469124] task: ffff88003716a700 task.stack: ffff88005872c000
[ 3929.469449] RIP: 0010:__kmalloc_track_caller+0x117/0x1be
[ 3929.469746] RSP: 0018:ffff88005872f6a0 EFLAGS: 00010246
[ 3929.470042] RAX: 00000000000002de RBX: 0000000058a59000 RCX: 00000000000002df
[ 3929.470406] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff821f7020
[ 3929.470770] RBP: ffff88005872f6e8 R08: 000000000001f010 R09: 0000000000000000
[ 3929.471133] R10: ffff88005872f730 R11: 0000000000008cdd R12: ff006d75646d7564
[ 3929.471496] R13: 00000000014000c0 R14: ffff88005b403c00 R15: ffff88005b403c00
[ 3929.471869] FS:  00007f0b70480740(0000) GS:ffff88005d980000(0000) knlGS:0000000000000000
[ 3929.472286] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3929.472677] CR2: 00007ffcee4f3000 CR3: 0000000059d45000 CR4: 00000000000406e0
[ 3929.473209] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3929.474109] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 3929.474873] Call Trace:
[ 3929.475337]  ? kstrdup_const+0x23/0x25
[ 3929.475863]  kstrdup+0x2e/0x4b
[ 3929.476338]  kstrdup_const+0x23/0x25
[ 3929.478084]  __kernfs_new_node+0x28/0xbc
[ 3929.478478]  kernfs_new_node+0x35/0x55
[ 3929.478929]  kernfs_create_link+0x23/0x76
[ 3929.479478]  sysfs_do_create_link_sd.isra.2+0x85/0xd7
[ 3929.480096]  sysfs_create_link+0x33/0x35
[ 3929.480649]  device_add+0x200/0x589
[ 3929.481184]  netdev_register_kobject+0x7c/0x12f
[ 3929.481711]  register_netdevice+0x373/0x471
[ 3929.482174]  rtnl_newlink+0x614/0x729
[ 3929.482610]  ? rtnl_newlink+0x17f/0x729
[ 3929.483080]  rtnetlink_rcv_msg+0x188/0x197
[ 3929.483533]  ? rcu_read_unlock+0x3e/0x5f
[ 3929.483984]  ? rtnl_newlink+0x729/0x729
[ 3929.484420]  netlink_rcv_skb+0x6c/0xce
[ 3929.484858]  rtnetlink_rcv+0x23/0x2a
[ 3929.485291]  netlink_unicast+0x103/0x181
[ 3929.485735]  netlink_sendmsg+0x326/0x337
[ 3929.486181]  sock_sendmsg_nosec+0x14/0x3f
[ 3929.486614]  sock_sendmsg+0x29/0x2e
[ 3929.486973]  ___sys_sendmsg+0x209/0x28b
[ 3929.487340]  ? do_raw_spin_unlock+0xcd/0xf8
[ 3929.487719]  ? _raw_spin_unlock+0x27/0x31
[ 3929.488092]  ? __handle_mm_fault+0x651/0xdb1
[ 3929.488471]  ? check_chain_key+0xb0/0xfd
[ 3929.488847]  __sys_sendmsg+0x45/0x63
[ 3929.489206]  ? __sys_sendmsg+0x45/0x63
[ 3929.489576]  SyS_sendmsg+0x19/0x1b
[ 3929.489901]  entry_SYSCALL_64_fastpath+0x23/0xc2
[ 3929.490172] RIP: 0033:0x7f0b6fb93690
[ 3929.490423] RSP: 002b:00007ffcee4ed588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[ 3929.490881] RAX: ffffffffffffffda RBX: ffffffff810d278c RCX: 00007f0b6fb93690
[ 3929.491198] RDX: 0000000000000000 RSI: 00007ffcee4ed5d0 RDI: 0000000000000003
[ 3929.491521] RBP: ffff88005872ff98 R08: 0000000000000001 R09: 0000000000000000
[ 3929.491801] R10: 00007ffcee4ed350 R11: 0000000000000246 R12: 0000000000000002
[ 3929.492075] R13: 000000000066f1a0 R14: 00007ffcee4f5680 R15: 0000000000000000
[ 3929.492352]  ? trace_hardirqs_off_caller+0xa7/0xcf
[ 3929.492590] Code: 8b 45 c0 48 8b 45 b8 74 17 48 8b 4d c8 83 ca ff 44
89 ee 4c 89 f7 e8 83 ca ff ff 49 89 c4 eb 49 49 63 56 20 48 8d 48 01 4d
8b 06 <49> 8b 1c 14 48 89 c2 4c 89 e0 65 49 0f c7 08 0f 94 c0 83 f0 01
[ 3929.493335] RIP: __kmalloc_track_caller+0x117/0x1be RSP: ffff88005872f6a0

Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Fixes: f07d1501 ("multiq: Further multiqueue cleanup")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit below added a call to the ->destroy() callback for all qdiscs
which failed in their ->init(), but some were not prepared for such
change and can't handle partially initialized qdisc. HTB is one of them
and if any error occurs before the qdisc watchdog timer and qdisc work are
initialized then we can hit either a null ptr deref (timer->base) when
canceling in ->destroy or lockdep error info about trying to register
a non-static key and a stack dump. So to fix these two move the watchdog
timer and workqueue init before anything that can err out.
To reproduce userspace needs to send broken htb qdisc create request,
tested with a modified tc (q_htb.c).

Trace log:
[ 2710.897602] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 2710.897977] IP: hrtimer_active+0x17/0x8a
[ 2710.898174] PGD 58fab067
[ 2710.898175] P4D 58fab067
[ 2710.898353] PUD 586c0067
[ 2710.898531] PMD 0
[ 2710.898710]
[ 2710.899045] Oops: 0000 [#1] SMP
[ 2710.899232] Modules linked in:
[ 2710.899419] CPU: 1 PID: 950 Comm: tc Not tainted 4.13.0-rc6+ #54
[ 2710.899646] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 2710.900035] task: ffff880059ed2700 task.stack: ffff88005ad4c000
[ 2710.900262] RIP: 0010:hrtimer_active+0x17/0x8a
[ 2710.900467] RSP: 0018:ffff88005ad4f960 EFLAGS: 00010246
[ 2710.900684] RAX: 0000000000000000 RBX: ffff88003701e298 RCX: 0000000000000000
[ 2710.900933] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88003701e298
[ 2710.901177] RBP: ffff88005ad4f980 R08: 0000000000000001 R09: 0000000000000001
[ 2710.901419] R10: ffff88005ad4f800 R11: 0000000000000400 R12: 0000000000000000
[ 2710.901663] R13: ffff88003701e298 R14: ffffffff822a4540 R15: ffff88005ad4fac0
[ 2710.901907] FS:  00007f2f5e90f740(0000) GS:ffff88005d880000(0000) knlGS:0000000000000000
[ 2710.902277] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 2710.902500] CR2: 0000000000000000 CR3: 0000000058ca3000 CR4: 00000000000406e0
[ 2710.902744] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 2710.902977] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 2710.903180] Call Trace:
[ 2710.903332]  hrtimer_try_to_cancel+0x1a/0x93
[ 2710.903504]  hrtimer_cancel+0x15/0x20
[ 2710.903667]  qdisc_watchdog_cancel+0x12/0x14
[ 2710.903866]  htb_destroy+0x2e/0xf7
[ 2710.904097]  qdisc_create+0x377/0x3fd
[ 2710.904330]  tc_modify_qdisc+0x4d2/0x4fd
[ 2710.904511]  rtnetlink_rcv_msg+0x188/0x197
[ 2710.904682]  ? rcu_read_unlock+0x3e/0x5f
[ 2710.904849]  ? rtnl_newlink+0x729/0x729
[ 2710.905017]  netlink_rcv_skb+0x6c/0xce
[ 2710.905183]  rtnetlink_rcv+0x23/0x2a
[ 2710.905345]  netlink_unicast+0x103/0x181
[ 2710.905511]  netlink_sendmsg+0x326/0x337
[ 2710.905679]  sock_sendmsg_nosec+0x14/0x3f
[ 2710.905847]  sock_sendmsg+0x29/0x2e
[ 2710.906010]  ___sys_sendmsg+0x209/0x28b
[ 2710.906176]  ? do_raw_spin_unlock+0xcd/0xf8
[ 2710.906346]  ? _raw_spin_unlock+0x27/0x31
[ 2710.906514]  ? __handle_mm_fault+0x651/0xdb1
[ 2710.906685]  ? check_chain_key+0xb0/0xfd
[ 2710.906855]  __sys_sendmsg+0x45/0x63
[ 2710.907018]  ? __sys_sendmsg+0x45/0x63
[ 2710.907185]  SyS_sendmsg+0x19/0x1b
[ 2710.907344]  entry_SYSCALL_64_fastpath+0x23/0xc2

Note that probably this bug goes further back because the default qdisc
handling always calls ->destroy on init failure too.

Fixes: 87b60cfa ("net_sched: fix error recovery at qdisc creation")
Fixes: 0fbbeb1b ("[PKT_SCHED]: Fix missing qdisc_destroy() in qdisc_create_dflt()")
Signed-off-by: NNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Typically, each TC filter has its own action. All the actions of the
same type are saved in its hash table. But the hash buckets are too
small that it degrades to a list. And the performance is greatly
affected. For example, it takes about 0m11.914s to insert 64K rules.
If we convert the hash table to IDR, it only takes about 0m1.500s.
The improvement is huge.

But please note that the test result is based on previous patch that
cls_flower uses IDR.
Signed-off-by: NChris Mi <chrism@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently, all filters with the same priority are linked in a doubly
linked list. Every filter should have a unique handle. To make the
handle unique, we need to iterate the list every time to see if the
handle exists or not when inserting a new filter. It is time-consuming.
For example, it takes about 5m3.169s to insert 64K rules.

This patch changes cls_flower to use IDR. With this patch, it
takes about 0m1.127s to insert 64K rules. The improvement is huge.

But please note that in this testing, all filters share the same action.
If every filter has a unique action, that is another bottleneck.
Follow-up patch in this patchset addresses that.
Signed-off-by: NChris Mi <chrism@mellanox.com>
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch handles a default IFE type if it's not given by user space
netlink api. The default IFE type will be the registered ethertype by
IEEE for IFE ForCES.
Signed-off-by: NAlexander Aring <aring@mojatatu.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The commit 520ac30f ("net_sched: drop packets after root qdisc lock
is released) made a big change of tc for performance. But there are
some points which are not changed in SFQ enqueue operation.
1. Fail to find the SFQ hash slot;
2. When the queue is full;

Now use qdisc_drop instead free skb directly.
Signed-off-by: NGao Feng <gfree.wind@vip.163.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>