wireguard-linux/net/sched/sch_htb.c, branch jd/unified-crypt-queue

net: sched: sch_htb: don't call qdisc_put() while holding tree lock

2019-09-27T10:13:55Z

Recent changes that removed rtnl dependency from rules update path of tc also made tcf_block_put() function sleeping. This function is called from ops->destroy() of several Qdisc implementations, which in turn is called by qdisc_put(). Some Qdiscs call qdisc_put() while holding sch tree spinlock, which results sleeping-while-atomic BUG. Steps to reproduce for htb: tc qdisc add dev ens1f0 root handle 1: htb default 12 tc class add dev ens1f0 parent 1: classid 1:1 htb rate 100kbps ceil 100kbps tc qdisc add dev ens1f0 parent 1:1 handle 40: sfq perturb 10 tc class add dev ens1f0 parent 1:1 classid 1:2 htb rate 100kbps ceil 100kbps Resulting dmesg: [ 4791.148551] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:909 [ 4791.151354] in_atomic(): 1, irqs_disabled(): 0, pid: 27273, name: tc [ 4791.152805] INFO: lockdep is turned off. [ 4791.153605] CPU: 19 PID: 27273 Comm: tc Tainted: G W 5.3.0-rc8+ #721 [ 4791.154336] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017 [ 4791.155075] Call Trace: [ 4791.155803] dump_stack+0x85/0xc0 [ 4791.156529] ___might_sleep.cold+0xac/0xbc [ 4791.157251] __mutex_lock+0x5b/0x960 [ 4791.157966] ? console_unlock+0x363/0x5d0 [ 4791.158676] ? tcf_chain0_head_change_cb_del.isra.0+0x1b/0xf0 [ 4791.159395] ? tcf_chain0_head_change_cb_del.isra.0+0x1b/0xf0 [ 4791.160103] tcf_chain0_head_change_cb_del.isra.0+0x1b/0xf0 [ 4791.160815] tcf_block_put_ext.part.0+0x21/0x50 [ 4791.161530] tcf_block_put+0x50/0x70 [ 4791.162233] sfq_destroy+0x15/0x50 [sch_sfq] [ 4791.162936] qdisc_destroy+0x5f/0x160 [ 4791.163642] htb_change_class.cold+0x5df/0x69d [sch_htb] [ 4791.164505] tc_ctl_tclass+0x19d/0x480 [ 4791.165360] rtnetlink_rcv_msg+0x170/0x4b0 [ 4791.166191] ? netlink_deliver_tap+0x95/0x400 [ 4791.166907] ? rtnl_dellink+0x2d0/0x2d0 [ 4791.167625] netlink_rcv_skb+0x49/0x110 [ 4791.168345] netlink_unicast+0x171/0x200 [ 4791.169058] netlink_sendmsg+0x224/0x3f0 [ 4791.169771] sock_sendmsg+0x5e/0x60 [ 4791.170475] ___sys_sendmsg+0x2ae/0x330 [ 4791.171183] ? ___sys_recvmsg+0x159/0x1f0 [ 4791.171894] ? do_wp_page+0x9c/0x790 [ 4791.172595] ? __handle_mm_fault+0xcd3/0x19e0 [ 4791.173309] __sys_sendmsg+0x59/0xa0 [ 4791.174024] do_syscall_64+0x5c/0xb0 [ 4791.174725] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 4791.175435] RIP: 0033:0x7f0aa41497b8 [ 4791.176129] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 65 8f 0c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 89 5 4 [ 4791.177532] RSP: 002b:00007fff4e37d588 EFLAGS: 00000246 ORIG_RAX: 000000000000002e [ 4791.178243] RAX: ffffffffffffffda RBX: 000000005d8132f7 RCX: 00007f0aa41497b8 [ 4791.178947] RDX: 0000000000000000 RSI: 00007fff4e37d5f0 RDI: 0000000000000003 [ 4791.179662] RBP: 0000000000000000 R08: 0000000000000001 R09: 00000000020149a0 [ 4791.180382] R10: 0000000000404eda R11: 0000000000000246 R12: 0000000000000001 [ 4791.181100] R13: 000000000047f640 R14: 0000000000000000 R15: 0000000000000000 In htb_change_class() function save parent->leaf.q to local temporary variable and put reference to it after sch tree lock is released in order not to call potentially sleeping cls API in atomic section. This is safe to do because Qdisc has already been reset by qdisc_purge_queue() inside sch tree lock critical section. Fixes: c266f64dbfa2 ("net: sched: protect block state with mutex") Signed-off-by: Vlad Buslov Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

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 Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

sch_htb: redefine htb qdisc overlimits

2019-05-06T04:55:20Z

In commit 3c75f6ee139d ("net_sched: sch_htb: add per class overlimits counter") we added an overlimits counter for each HTB class which could properly reflect how many times we use up all the bandwidth on each class. However, the overlimits counter in HTB qdisc does not, it is way bigger than the sum of each HTB class. In fact, this qdisc overlimits counter increases when we have no skb to dequeue, which happens more often than we run out of bandwidth. It makes more sense to make this qdisc overlimits counter just be a sum of each HTB class, in case people still get confused. I have verified this patch with one single HTB class, where HTB qdisc counters now always match HTB class counters as expected. Eric suggested we could fold this field into 'direct_pkts' as we only use its 32bit on 64bit CPU, this saves one cache line. Cc: Eric Dumazet Signed-off-by: Cong Wang Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

netlink: make validation more configurable for future strictness

2019-04-27T21:07:21Z

We currently have two levels of strict validation: 1) liberal (default) - undefined (type >= max) & NLA_UNSPEC attributes accepted - attribute length >= expected accepted - garbage at end of message accepted 2) strict (opt-in) - NLA_UNSPEC attributes accepted - attribute length >= expected accepted Split out parsing strictness into four different options: * TRAILING - check that there's no trailing data after parsing attributes (in message or nested) * MAXTYPE - reject attrs > max known type * UNSPEC - reject attributes with NLA_UNSPEC policy entries * STRICT_ATTRS - strictly validate attribute size The default for future things should be *everything*. The current *_strict() is a combination of TRAILING and MAXTYPE, and is renamed to _deprecated_strict(). The current regular parsing has none of this, and is renamed to *_parse_deprecated(). Additionally it allows us to selectively set one of the new flags even on old policies. Notably, the UNSPEC flag could be useful in this case, since it can be arranged (by filling in the policy) to not be an incompatible userspace ABI change, but would then going forward prevent forgetting attribute entries. Similar can apply to the POLICY flag. We end up with the following renames: * nla_parse -> nla_parse_deprecated * nla_parse_strict -> nla_parse_deprecated_strict * nlmsg_parse -> nlmsg_parse_deprecated * nlmsg_parse_strict -> nlmsg_parse_deprecated_strict * nla_parse_nested -> nla_parse_nested_deprecated * nla_validate_nested -> nla_validate_nested_deprecated Using spatch, of course: @@ expression TB, MAX, HEAD, LEN, POL, EXT; @@ -nla_parse(TB, MAX, HEAD, LEN, POL, EXT) +nla_parse_deprecated(TB, MAX, HEAD, LEN, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression NLH, HDRLEN, TB, MAX, POL, EXT; @@ -nlmsg_parse_strict(NLH, HDRLEN, TB, MAX, POL, EXT) +nlmsg_parse_deprecated_strict(NLH, HDRLEN, TB, MAX, POL, EXT) @@ expression TB, MAX, NLA, POL, EXT; @@ -nla_parse_nested(TB, MAX, NLA, POL, EXT) +nla_parse_nested_deprecated(TB, MAX, NLA, POL, EXT) @@ expression START, MAX, POL, EXT; @@ -nla_validate_nested(START, MAX, POL, EXT) +nla_validate_nested_deprecated(START, MAX, POL, EXT) @@ expression NLH, HDRLEN, MAX, POL, EXT; @@ -nlmsg_validate(NLH, HDRLEN, MAX, POL, EXT) +nlmsg_validate_deprecated(NLH, HDRLEN, MAX, POL, EXT) For this patch, don't actually add the strict, non-renamed versions yet so that it breaks compile if I get it wrong. Also, while at it, make nla_validate and nla_parse go down to a common __nla_validate_parse() function to avoid code duplication. Ultimately, this allows us to have very strict validation for every new caller of nla_parse()/nlmsg_parse() etc as re-introduced in the next patch, while existing things will continue to work as is. In effect then, this adds fully strict validation for any new command. Signed-off-by: Johannes Berg Signed-off-by: David S. Miller

netlink: make nla_nest_start() add NLA_F_NESTED flag

2019-04-27T21:03:44Z

Even if the NLA_F_NESTED flag was introduced more than 11 years ago, most netlink based interfaces (including recently added ones) are still not setting it in kernel generated messages. Without the flag, message parsers not aware of attribute semantics (e.g. wireshark dissector or libmnl's mnl_nlmsg_fprintf()) cannot recognize nested attributes and won't display the structure of their contents. Unfortunately we cannot just add the flag everywhere as there may be userspace applications which check nlattr::nla_type directly rather than through a helper masking out the flags. Therefore the patch renames nla_nest_start() to nla_nest_start_noflag() and introduces nla_nest_start() as a wrapper adding NLA_F_NESTED. The calls which add NLA_F_NESTED manually are rewritten to use nla_nest_start(). Except for changes in include/net/netlink.h, the patch was generated using this semantic patch: @@ expression E1, E2; @@ -nla_nest_start(E1, E2) +nla_nest_start_noflag(E1, E2) @@ expression E1, E2; @@ -nla_nest_start_noflag(E1, E2 | NLA_F_NESTED) +nla_nest_start(E1, E2) Signed-off-by: Michal Kubecek Acked-by: Jiri Pirko Acked-by: David Ahern Signed-off-by: David S. Miller

net: sched: introduce and use qdisc tree flush/purge helpers

2019-04-01T21:50:13Z

The same code to flush qdisc tree and purge the qdisc queue is duplicated in many places and in most cases it does not respect NOLOCK qdisc: the global backlog len is used and the per CPU values are ignored. This change addresses the above, factoring-out the relevant code and using the helpers introduced by the previous patch to fetch the correct backlog len. Fixes: c5ad119fb6c0 ("net: sched: pfifo_fast use skb_array") Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

net: sched: introduce and use qstats read helpers

2019-04-01T21:50:13Z

Classful qdiscs can't access directly the child qdiscs backlog length: if such qdisc is NOLOCK, per CPU values should be accounted instead. Most qdiscs no not respect the above. As a result, qstats fetching for most classful qdisc is currently incorrect: if the child qdisc is NOLOCK, it always reports 0 len backlog. This change introduces a pair of helpers to safely fetch both backlog and qlen and use them in stats class dumping functions, fixing the above issue and cleaning a bit the code. DRR needs also to access the child qdisc queue length, so it needs custom handling. Fixes: c5ad119fb6c0 ("net: sched: pfifo_fast use skb_array") Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

sched: Avoid dereferencing skb pointer after child enqueue

2019-01-16T04:12:00Z

Parent qdiscs may dereference the pointer to the enqueued skb after enqueue. However, both CAKE and TBF call consume_skb() on the original skb when splitting GSO packets, leading to a potential use-after-free in the parent. Fix this by avoiding dereferencing the skb pointer after enqueueing to the child. Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller

net: sched: rename qdisc_destroy() to qdisc_put()

2018-09-26T03:17:35Z

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: Vlad Buslov Acked-by: Jiri Pirko Signed-off-by: David S. Miller

htb: use anonymous union for simplicity

2018-09-10T17:39:57Z

cl->leaf.q is slightly more readable than cl->un.leaf.q. Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Signed-off-by: David S. Miller