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2015-08-27net: sched: consolidate tc_classify{,_compat}Daniel Borkmann14-43/+38
For classifiers getting invoked via tc_classify(), we always need an extra function call into tc_classify_compat(), as both are being exported as symbols and tc_classify() itself doesn't do much except handling of reclassifications when tp->classify() returned with TC_ACT_RECLASSIFY. CBQ and ATM are the only qdiscs that directly call into tc_classify_compat(), all others use tc_classify(). When tc actions are being configured out in the kernel, tc_classify() effectively does nothing besides delegating. We could spare this layer and consolidate both functions. pktgen on single CPU constantly pushing skbs directly into the netif_receive_skb() path with a dummy classifier on ingress qdisc attached, improves slightly from 22.3Mpps to 23.1Mpps. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26net_sched: act_bpf: remove spinlock in fast pathAlexei Starovoitov1-17/+19
Similar to act_gact/act_mirred, act_bpf can be lockless in packet processing with extra care taken to free bpf programs after rcu grace period. Replacement of existing act_bpf (very rare) is done with synchronize_rcu() and final destruction is done from tc_action_ops->cleanup() callback that is called from tcf_exts_destroy()->tcf_action_destroy()->__tcf_hash_release() when bind and refcnt reach zero which is only possible when classifier is destroyed. Previous two patches fixed the last two classifiers (tcindex and rsvp) to call tcf_exts_destroy() from rcu callback. Similar to gact/mirred there is a race between prog->filter and prog->tcf_action. Meaning that the program being replaced may use previous default action if it happened to return TC_ACT_UNSPEC. act_mirred race betwen tcf_action and tcfm_dev is similar. In all cases the race is harmless. Long term we may want to improve the situation by replacing the whole tc_action->priv as single pointer instead of updating inner fields one by one. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26net_sched: convert rsvp to call tcf_exts_destroy from rcu callbackAlexei Starovoitov1-4/+14
Adjust destroy path of cls_rsvp to call tcf_exts_destroy() after rcu grace period. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26net_sched: convert tcindex to call tcf_exts_destroy from rcu callbackAlexei Starovoitov1-4/+25
Adjust destroy path of cls_tcindex to call tcf_exts_destroy() after rcu grace period. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26net_sched: act_bpf: remove unnecessary copyAlexei Starovoitov1-1/+1
Fix harmless typo and avoid unnecessary copy of empty 'prog' into unused 'strcut tcf_bpf_cfg old'. Fixes: f4eaed28c783 ("act_bpf: fix memory leaks when replacing bpf programs") Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-26net_sched: make tcf_hash_destroy() staticAlexei Starovoitov1-2/+1
tcf_hash_destroy() used once. Make it static. Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-21Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextPablo Neira Ayuso9-25/+38
Resolve conflicts with conntrack template fixes. Conflicts: net/netfilter/nf_conntrack_core.c net/netfilter/nf_synproxy_core.c net/netfilter/xt_CT.c Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-08-18net: sched: drop all special handling of tx_queue_len == 0Phil Sutter5-17/+9
Those were all workarounds for the formerly double meaning of tx_queue_len, which broke scheduling algorithms if untreated. Now that all in-tree drivers have been converted away from setting tx_queue_len = 0, it should be safe to drop these workarounds for categorically broken setups. Signed-off-by: Phil Sutter <phil@nwl.cc> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-17net: Change pseudohdr argument of inet_proto_csum_replace* to be a boolTom Herbert1-3/+4
inet_proto_csum_replace4,2,16 take a pseudohdr argument which indicates the checksum field carries a pseudo header. This argument should be a boolean instead of an int. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-18netfilter: nf_conntrack: add direction support for zonesDaniel Borkmann1-0/+1
This work adds a direction parameter to netfilter zones, so identity separation can be performed only in original/reply or both directions (default). This basically opens up the possibility of doing NAT with conflicting IP address/port tuples from multiple, isolated tenants on a host (e.g. from a netns) without requiring each tenant to NAT twice resp. to use its own dedicated IP address to SNAT to, meaning overlapping tuples can be made unique with the zone identifier in original direction, where the NAT engine will then allocate a unique tuple in the commonly shared default zone for the reply direction. In some restricted, local DNAT cases, also port redirection could be used for making the reply traffic unique w/o requiring SNAT. The consensus we've reached and discussed at NFWS and since the initial implementation [1] was to directly integrate the direction meta data into the existing zones infrastructure, as opposed to the ct->mark approach we proposed initially. As we pass the nf_conntrack_zone object directly around, we don't have to touch all call-sites, but only those, that contain equality checks of zones. Thus, based on the current direction (original or reply), we either return the actual id, or the default NF_CT_DEFAULT_ZONE_ID. CT expectations are direction-agnostic entities when expectations are being compared among themselves, so we can only use the identifier in this case. Note that zone identifiers can not be included into the hash mix anymore as they don't contain a "stable" value that would be equal for both directions at all times, f.e. if only zone->id would unconditionally be xor'ed into the table slot hash, then replies won't find the corresponding conntracking entry anymore. If no particular direction is specified when configuring zones, the behaviour is exactly as we expect currently (both directions). Support has been added for the CT netlink interface as well as the x_tables raw CT target, which both already offer existing interfaces to user space for the configuration of zones. Below a minimal, simplified collision example (script in [2]) with netperf sessions: +--- tenant-1 ---+ mark := 1 | netperf |--+ +----------------+ | CT zone := mark [ORIGINAL] [ip,sport] := X +--------------+ +--- gateway ---+ | mark routing |--| SNAT |-- ... + +--------------+ +---------------+ | +--- tenant-2 ---+ | ~~~|~~~ | netperf |--+ +-----------+ | +----------------+ mark := 2 | netserver |------ ... + [ip,sport] := X +-----------+ [ip,port] := Y On the gateway netns, example: iptables -t raw -A PREROUTING -j CT --zone mark --zone-dir ORIGINAL iptables -t nat -A POSTROUTING -o <dev> -j SNAT --to-source <ip> --random-fully iptables -t mangle -A PREROUTING -m conntrack --ctdir ORIGINAL -j CONNMARK --save-mark iptables -t mangle -A POSTROUTING -m conntrack --ctdir REPLY -j CONNMARK --restore-mark conntrack dump from gateway netns: netperf -H 10.1.1.2 -t TCP_STREAM -l60 -p12865,5555 from each tenant netns tcp 6 431995 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=1 src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=1024 [ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1 tcp 6 431994 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=2 src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=5555 [ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=1 tcp 6 299 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=39438 dport=33768 zone-orig=1 src=10.1.1.2 dst=10.1.1.1 sport=33768 dport=39438 [ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1 tcp 6 300 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=32889 dport=40206 zone-orig=2 src=10.1.1.2 dst=10.1.1.1 sport=40206 dport=32889 [ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=2 Taking this further, test script in [2] creates 200 tenants and runs original-tuple colliding netperf sessions each. A conntrack -L dump in the gateway netns also confirms 200 overlapping entries, all in ESTABLISHED state as expected. I also did run various other tests with some permutations of the script, to mention some: SNAT in random/random-fully/persistent mode, no zones (no overlaps), static zones (original, reply, both directions), etc. [1] http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.devel/57412/ [2] https://paste.fedoraproject.org/242835/65657871/ Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-08-17net: sch_generic: react upon IFF_NO_QUEUE flagPhil Sutter1-2/+4
Handle IFF_NO_QUEUE as alternative to tx_queue_len being zero. Signed-off-by: Phil Sutter <phil@nwl.cc> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2-3/+21
Conflicts: drivers/net/ethernet/cavium/Kconfig The cavium conflict was overlapping dependency changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-11netfilter: nf_conntrack: push zone object into functionsDaniel Borkmann1-1/+4
This patch replaces the zone id which is pushed down into functions with the actual zone object. It's a bigger one-time change, but needed for later on extending zones with a direction parameter, and thus decoupling this additional information from all call-sites. No functional changes in this patch. The default zone becomes a global const object, namely nf_ct_zone_dflt and will be returned directly in various cases, one being, when there's f.e. no zoning support. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-08-03act_bpf: properly support late binding of bpf action to a classifierDaniel Borkmann1-24/+27
Since the introduction of the BPF action in d23b8ad8ab23 ("tc: add BPF based action"), late binding was not working as expected. I.e. setting the action part for a classifier only via 'bpf index <num>', where <num> is the index of an existing action, is being rejected by the kernel due to other missing parameters. It doesn't make sense to require these parameters such as BPF opcodes etc, as they are not going to be used anyway: in this case, they're just allocated/parsed and then freed again w/o doing anything meaningful. Instead, parse and verify the remaining parameters *after* the test on tcf_hash_check(), when we really know that we're dealing with creation of a new action or replacement of an existing one and where late binding is thus irrelevant. After patch, test case is now working: FOO="1,6 0 0 4294967295," tc actions add action bpf bytecode "$FOO" tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 action bpf index 1 tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 1 ref 2 bind 1 tc filter show dev foo filter protocol all pref 49152 bpf filter protocol all pref 49152 bpf handle 0x1 flowid 1:1 bytecode '1,6 0 0 4294967295' action order 1: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 1 ref 2 bind 1 Late binding of a BPF action can be useful for preloading maps (e.g. before they hit traffic) in case of eBPF programs, or to share a single eBPF action with multiple classifiers. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-03act_mirred: avoid calling tcf_hash_release() when bindingWANG Cong1-0/+2
When we share an action within a filter, the bind refcnt should increase, therefore we should not call tcf_hash_release(). Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-08-02fq_codel: explicitly reset flows in ->reset()Eric Dumazet1-3/+19
Alex reported the following crash when using fq_codel with htb: crash> bt PID: 630839 TASK: ffff8823c990d280 CPU: 14 COMMAND: "tc" [... snip ...] #8 [ffff8820ceec17a0] page_fault at ffffffff8160a8c2 [exception RIP: htb_qlen_notify+24] RIP: ffffffffa0841718 RSP: ffff8820ceec1858 RFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88241747b400 RDX: ffff88241747b408 RSI: 0000000000000000 RDI: ffff8811fb27d000 RBP: ffff8820ceec1868 R8: ffff88120cdeff24 R9: ffff88120cdeff30 R10: 0000000000000bd4 R11: ffffffffa0840919 R12: ffffffffa0843340 R13: 0000000000000000 R14: 0000000000000001 R15: ffff8808dae5c2e8 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 #9 [...] qdisc_tree_decrease_qlen at ffffffff81565375 #10 [...] fq_codel_dequeue at ffffffffa084e0a0 [sch_fq_codel] #11 [...] fq_codel_reset at ffffffffa084e2f8 [sch_fq_codel] #12 [...] qdisc_destroy at ffffffff81560d2d #13 [...] htb_destroy_class at ffffffffa08408f8 [sch_htb] #14 [...] htb_put at ffffffffa084095c [sch_htb] #15 [...] tc_ctl_tclass at ffffffff815645a3 #16 [...] rtnetlink_rcv_msg at ffffffff81552cb0 [... snip ...] As Jamal pointed out, there is actually no need to call dequeue to purge the queued skb's in reset, data structures can be just reset explicitly. Therefore, we reset everything except config's and stats, so that we would have a fresh start after device flipping. Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM") Reported-by: Alex Gartrell <agartrell@fb.com> Cc: Alex Gartrell <agartrell@fb.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> [xiyou.wangcong@gmail.com: added codel_vars_init() and qdisc_qstats_backlog_dec()] Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-31Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller5-26/+57
Conflicts: arch/s390/net/bpf_jit_comp.c drivers/net/ethernet/ti/netcp_ethss.c net/bridge/br_multicast.c net/ipv4/ip_fragment.c All four conflicts were cases of simple overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-31act_pedit: check binding before calling tcf_hash_release()WANG Cong1-3/+2
When we share an action within a filter, the bind refcnt should increase, therefore we should not call tcf_hash_release(). Fixes: 1a29321ed045 ("net_sched: act: Dont increment refcnt on replace") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-30net: sched: fix refcount imbalance in actionsDaniel Borkmann1-5/+6
Since commit 55334a5db5cd ("net_sched: act: refuse to remove bound action outside"), we end up with a wrong reference count for a tc action. Test case 1: FOO="1,6 0 0 4294967295," BAR="1,6 0 0 4294967294," tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 \ action bpf bytecode "$FOO" tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 1 ref 1 bind 1 tc actions replace action bpf bytecode "$BAR" index 1 tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967294' default-action pipe index 1 ref 2 bind 1 tc actions replace action bpf bytecode "$FOO" index 1 tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 1 ref 3 bind 1 Test case 2: FOO="1,6 0 0 4294967295," tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 action ok tc actions show action gact action order 0: gact action pass random type none pass val 0 index 1 ref 1 bind 1 tc actions add action drop index 1 RTNETLINK answers: File exists [...] tc actions show action gact action order 0: gact action pass random type none pass val 0 index 1 ref 2 bind 1 tc actions add action drop index 1 RTNETLINK answers: File exists [...] tc actions show action gact action order 0: gact action pass random type none pass val 0 index 1 ref 3 bind 1 What happens is that in tcf_hash_check(), we check tcf_common for a given index and increase tcfc_refcnt and conditionally tcfc_bindcnt when we've found an existing action. Now there are the following cases: 1) We do a late binding of an action. In that case, we leave the tcfc_refcnt/tcfc_bindcnt increased and are done with the ->init() handler. This is correctly handeled. 2) We replace the given action, or we try to add one without replacing and find out that the action at a specific index already exists (thus, we go out with error in that case). In case of 2), we have to undo the reference count increase from tcf_hash_check() in the tcf_hash_check() function. Currently, we fail to do so because of the 'tcfc_bindcnt > 0' check which bails out early with an -EPERM error. Now, while commit 55334a5db5cd prevents 'tc actions del action ...' on an already classifier-bound action to drop the reference count (which could then become negative, wrap around etc), this restriction only accounts for invocations outside a specific action's ->init() handler. One possible solution would be to add a flag thus we possibly trigger the -EPERM ony in situations where it is indeed relevant. After the patch, above test cases have correct reference count again. Fixes: 55334a5db5cd ("net_sched: act: refuse to remove bound action outside") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-29act_bpf: fix memory leaks when replacing bpf programsDaniel Borkmann1-18/+35
We currently trigger multiple memory leaks when replacing bpf actions, besides others: comm "tc", pid 1909, jiffies 4294851310 (age 1602.796s) hex dump (first 32 bytes): 01 00 00 00 03 00 00 00 00 00 00 00 00 00 00 00 ................ 18 b0 98 6d 00 88 ff ff 00 00 00 00 00 00 00 00 ...m............ backtrace: [<ffffffff817e623e>] kmemleak_alloc+0x4e/0xb0 [<ffffffff8120a22d>] __vmalloc_node_range+0x1bd/0x2c0 [<ffffffff8120a37a>] __vmalloc+0x4a/0x50 [<ffffffff811a8d0a>] bpf_prog_alloc+0x3a/0xa0 [<ffffffff816c0684>] bpf_prog_create+0x44/0xa0 [<ffffffffa09ba4eb>] tcf_bpf_init+0x28b/0x3c0 [act_bpf] [<ffffffff816d7001>] tcf_action_init_1+0x191/0x1b0 [<ffffffff816d70a2>] tcf_action_init+0x82/0xf0 [<ffffffff816d4d12>] tcf_exts_validate+0xb2/0xc0 [<ffffffffa09b5838>] cls_bpf_modify_existing+0x98/0x340 [cls_bpf] [<ffffffffa09b5cd6>] cls_bpf_change+0x1a6/0x274 [cls_bpf] [<ffffffff816d56e5>] tc_ctl_tfilter+0x335/0x910 [<ffffffff816b9145>] rtnetlink_rcv_msg+0x95/0x240 [<ffffffff816df34f>] netlink_rcv_skb+0xaf/0xc0 [<ffffffff816b909e>] rtnetlink_rcv+0x2e/0x40 [<ffffffff816deaaf>] netlink_unicast+0xef/0x1b0 Issue is that the old content from tcf_bpf is allocated and needs to be released when we replace it. We seem to do that since the beginning of act_bpf on the filter and insns, later on the name as well. Example test case, after patch: # FOO="1,6 0 0 4294967295," # BAR="1,6 0 0 4294967294," # tc actions add action bpf bytecode "$FOO" index 2 # tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 2 ref 1 bind 0 # tc actions replace action bpf bytecode "$BAR" index 2 # tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967294' default-action pipe index 2 ref 1 bind 0 # tc actions replace action bpf bytecode "$FOO" index 2 # tc actions show action bpf action order 0: bpf bytecode '1,6 0 0 4294967295' default-action pipe index 2 ref 1 bind 0 # tc actions del action bpf index 2 [...] # echo "scan" > /sys/kernel/debug/kmemleak # cat /sys/kernel/debug/kmemleak | grep "comm \"tc\"" | wc -l 0 Fixes: d23b8ad8ab23 ("tc: add BPF based action") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-24sch_choke: drop all packets in queue during resetWANG Cong1-0/+13
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-24sch_plug: purge buffered packets during resetWANG Cong1-0/+1
Otherwise the skbuff related structures are not correctly refcount'ed. Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller6-7/+20
Conflicts: net/bridge/br_mdb.c br_mdb.c conflict was a function call being removed to fix a bug in 'net' but whose signature was changed in 'net-next'. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-21sched: cls_flow: fix panic on filter replaceDaniel Borkmann1-2/+3
The following test case causes a NULL pointer dereference in cls_flow: tc filter add dev foo parent 1: handle 0x1 flow hash keys dst action ok tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ flow hash keys mark action drop To be more precise, actually two different panics are fixed, the first occurs because tcf_exts_init() is not called on the newly allocated filter when we do a replace. And the second panic uncovered after that happens since the arguments of list_replace_rcu() are swapped, the old element needs to be the first argument and the new element the second. Fixes: 70da9f0bf999 ("net: sched: cls_flow use RCU") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.r.fastabend@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-21sched: cls_flower: fix panic on filter replaceDaniel Borkmann1-1/+1
The following test case causes a NULL pointer dereference in cls_flower: tc filter add dev foo parent 1: flower eth_type ipv4 action ok flowid 1:1 tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ flower eth_type ipv6 action ok flowid 1:1 The problem is that commit 77b9900ef53a ("tc: introduce Flower classifier") accidentally swapped the arguments of list_replace_rcu(), the old element needs to be the first argument and the new element the second. Fixes: 77b9900ef53a ("tc: introduce Flower classifier") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-21sched: cls_bpf: fix panic on filter replaceDaniel Borkmann1-1/+1
The following test case causes a NULL pointer dereference in cls_bpf: FOO="1,6 0 0 4294967295," tc filter add dev foo parent 1: bpf bytecode "$FOO" flowid 1:1 action ok tc filter replace dev foo parent 1: pref 49152 handle 0x1 \ bpf bytecode "$FOO" flowid 1:1 action drop The problem is that commit 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") accidentally swapped the arguments of list_replace_rcu(), the old element needs to be the first argument and the new element the second. Fixes: 1f947bf151e9 ("net: sched: rcu'ify cls_bpf") Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.r.fastabend@intel.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-20cls_cgroup: factor out classid retrievalDaniel Borkmann1-21/+2
Split out retrieving the cgroups net_cls classid retrieval into its own function, so that it can be reused later on from other parts of the traffic control subsystem. If there's no skb->sk, then the small helper returns 0 as well, which in cls_cgroup terms means 'could not classify'. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-15tc: act_bpf: fix memory leakAlexei Starovoitov1-0/+3
prog->bpf_ops is populated when act_bpf is used with classic BPF and prog->bpf_name is optionally used with extended BPF. Fix memory leak when act_bpf is released. Fixes: d23b8ad8ab23 ("tc: add BPF based action") Fixes: a8cb5f556b56 ("act_bpf: add initial eBPF support for actions") Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-15fq_codel: fix return value of fq_codel_drop()WANG Cong1-1/+10
The ->drop() is supposed to return the number of bytes it dropped, however fq_codel_drop() returns the index of the flow where it drops a packet from. Fix this by introducing a helper to wrap fq_codel_drop(). Cc: Eric Dumazet <edumazet@google.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-15net_sched: fix a use-after-free in sfqWANG Cong1-1/+1
Fixes: 25331d6ce42b ("net: sched: implement qstat helper routines") Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-15pkt_sched: sch_qfq: remove unused member of struct qfq_schedAndrea Parri1-1/+0
The member (u32) "num_active_agg" of struct qfq_sched has been unused since its introduction in 462dbc9101acd38e92eda93c0726857517a24bbd "pkt_sched: QFQ Plus: fair-queueing service at DRR cost" and (AFAICT) there is no active plan to use it; this removes the member. Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Acked-by: Paolo Valente <paolo.valente@unimore.it> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-15fq_codel: fix a use-after-freeWANG Cong1-1/+1
Fixes: 25331d6ce42b ("net: sched: implement qstat helper routines") Cc: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net_sched: act_mirred: remove spinlock in fast pathEric Dumazet1-27/+30
Like act_gact, act_mirred can be lockless in packet processing 1) Use percpu stats 2) update lastuse only every clock tick to avoid false sharing 3) use rcu to protect tcfm_dev 4) Remove spinlock usage, as it is no longer needed. Next step : add multi queue capability to ifb device Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.fastabend@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net_sched: act_gact: remove spinlock in fast pathEric Dumazet1-10/+7
Final step for gact RCU operation : 1) Use percpu stats 2) update lastuse only every clock tick to avoid false sharing 3) Remove spinlock acquisition, as it is no longer needed. Since this is the last contended lock in packet RX when tc gact is used, this gives impressive gain. My host with 8 RX queues was handling 5 Mpps before the patch, and more than 11 Mpps after patch. Tested: On receiver : dev=eth0 tc qdisc del dev $dev ingress 2>/dev/null tc qdisc add dev $dev ingress tc filter del dev $dev root pref 10 2>/dev/null tc filter del dev $dev pref 10 2>/dev/null tc filter add dev $dev est 1sec 4sec parent ffff: protocol ip prio 1 \ u32 match ip src 7.0.0.0/8 flowid 1:15 action drop Sender sends packets flood from 7/8 network Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net_sched: act_gact: read tcfg_ptype onceEric Dumazet1-7/+7
Third step for gact RCU operation : Following patch will get rid of spinlock protection, so we need to read tcfg_ptype once. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net_sched: act_gact: use a separate packet counters for gact_determ()Eric Dumazet1-1/+3
Second step for gact RCU operation : We want to get rid of the spinlock protecting gact operations. Stats (packets/bytes) will soon be per cpu. gact_determ() would not work without a central packet counter, so lets add it for this mode. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net_sched: act_gact: make tcfg_pval non zeroEric Dumazet1-3/+9
First step for gact RCU operation : Instead of testing if tcfg_pval is zero or not, just make it 1. No change in behavior, but slightly faster code. The smp_rmb()/smp_wmb() barriers, while not strictly needed at this stage are added for upcoming spinlock removal. Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-08net: sched: add percpu stats to actionsEric Dumazet12-21/+54
Reuse existing percpu infrastructure John Fastabend added for qdisc. This patch adds a new cpustats parameter to tcf_hash_create() and all actions pass false, meaning this patch should have no effect yet. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-25net: sched: flower fix typoJamal Hadi Salim1-2/+2
Fix typo in the validation rules for flower's attributes Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-24Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds21-175/+834
Pull networking updates from David Miller: 1) Add TX fast path in mac80211, from Johannes Berg. 2) Add TSO/GRO support to ibmveth, from Thomas Falcon 3) Move away from cached routes in ipv6, just like ipv4, from Martin KaFai Lau. 4) Lots of new rhashtable tests, from Thomas Graf. 5) Run ingress qdisc lockless, from Alexei Starovoitov. 6) Allow servers to fetch TCP packet headers for SYN packets of new connections, for fingerprinting. From Eric Dumazet. 7) Add mode parameter to pktgen, for testing receive. From Alexei Starovoitov. 8) Cache access optimizations via simplifications of build_skb(), from Alexander Duyck. 9) Move page frag allocator under mm/, also from Alexander. 10) Add xmit_more support to hv_netvsc, from KY Srinivasan. 11) Add a counter guard in case we try to perform endless reclassify loops in the packet scheduler. 12) Extern flow dissector to be programmable and use it in new "Flower" classifier. From Jiri Pirko. 13) AF_PACKET fanout rollover fixes, performance improvements, and new statistics. From Willem de Bruijn. 14) Add netdev driver for GENEVE tunnels, from John W Linville. 15) Add ingress netfilter hooks and filtering, from Pablo Neira Ayuso. 16) Fix handling of epoll edge triggers in TCP, from Eric Dumazet. 17) Add an ECN retry fallback for the initial TCP handshake, from Daniel Borkmann. 18) Add tail call support to BPF, from Alexei Starovoitov. 19) Add several pktgen helper scripts, from Jesper Dangaard Brouer. 20) Add zerocopy support to AF_UNIX, from Hannes Frederic Sowa. 21) Favor even port numbers for allocation to connect() requests, and odd port numbers for bind(0), in an effort to help avoid ip_local_port_range exhaustion. From Eric Dumazet. 22) Add Cavium ThunderX driver, from Sunil Goutham. 23) Allow bpf programs to access skb_iif and dev->ifindex SKB metadata, from Alexei Starovoitov. 24) Add support for T6 chips in cxgb4vf driver, from Hariprasad Shenai. 25) Double TCP Small Queues default to 256K to accomodate situations like the XEN driver and wireless aggregation. From Wei Liu. 26) Add more entropy inputs to flow dissector, from Tom Herbert. 27) Add CDG congestion control algorithm to TCP, from Kenneth Klette Jonassen. 28) Convert ipset over to RCU locking, from Jozsef Kadlecsik. 29) Track and act upon link status of ipv4 route nexthops, from Andy Gospodarek. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1670 commits) bridge: vlan: flush the dynamically learned entries on port vlan delete bridge: multicast: add a comment to br_port_state_selection about blocking state net: inet_diag: export IPV6_V6ONLY sockopt stmmac: troubleshoot unexpected bits in des0 & des1 net: ipv4 sysctl option to ignore routes when nexthop link is down net: track link-status of ipv4 nexthops net: switchdev: ignore unsupported bridge flags net: Cavium: Fix MAC address setting in shutdown state drivers: net: xgene: fix for ACPI support without ACPI ip: report the original address of ICMP messages net/mlx5e: Prefetch skb data on RX net/mlx5e: Pop cq outside mlx5e_get_cqe net/mlx5e: Remove mlx5e_cq.sqrq back-pointer net/mlx5e: Remove extra spaces net/mlx5e: Avoid TX CQE generation if more xmit packets expected net/mlx5e: Avoid redundant dev_kfree_skb() upon NOP completion net/mlx5e: Remove re-assignment of wq type in mlx5e_enable_rq() net/mlx5e: Use skb_shinfo(skb)->gso_segs rather than counting them net/mlx5e: Static mapping of netdev priv resources to/from netdev TX queues net/mlx4_en: Use HW counters for rx/tx bytes/packets in PF device ...
2015-06-22Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds1-4/+1
Pull timer updates from Thomas Gleixner: "A rather largish update for everything time and timer related: - Cache footprint optimizations for both hrtimers and timer wheel - Lower the NOHZ impact on systems which have NOHZ or timer migration disabled at runtime. - Optimize run time overhead of hrtimer interrupt by making the clock offset updates smarter - hrtimer cleanups and removal of restrictions to tackle some problems in sched/perf - Some more leap second tweaks - Another round of changes addressing the 2038 problem - First step to change the internals of clock event devices by introducing the necessary infrastructure - Allow constant folding for usecs/msecs_to_jiffies() - The usual pile of clockevent/clocksource driver updates The hrtimer changes contain updates to sched, perf and x86 as they depend on them plus changes all over the tree to cleanup API changes and redundant code, which got copied all over the place. The y2038 changes touch s390 to remove the last non 2038 safe code related to boot/persistant clock" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits) clocksource: Increase dependencies of timer-stm32 to limit build wreckage timer: Minimize nohz off overhead timer: Reduce timer migration overhead if disabled timer: Stats: Simplify the flags handling timer: Replace timer base by a cpu index timer: Use hlist for the timer wheel hash buckets timer: Remove FIFO "guarantee" timers: Sanitize catchup_timer_jiffies() usage hrtimer: Allow hrtimer::function() to free the timer seqcount: Introduce raw_write_seqcount_barrier() seqcount: Rename write_seqcount_barrier() hrtimer: Fix hrtimer_is_queued() hole hrtimer: Remove HRTIMER_STATE_MIGRATE selftest: Timers: Avoid signal deadlock in leap-a-day timekeeping: Copy the shadow-timekeeper over the real timekeeper last clockevents: Check state instead of mode in suspend/resume path selftests: timers: Add leap-second timer edge testing to leap-a-day.c ntp: Do leapsecond adjustment in adjtimex read path time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge ntp: Introduce and use SECS_PER_DAY macro instead of 86400 ...
2015-06-21pkt_sched: sch_qfq: remove redundant -if- control statementAndrea Parri1-2/+1
The control !hlist_unhashed() in qfq_destroy_agg() is unnecessary because already performed in hlist_del_init(), so remove it. Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-18net: sched: Simplify em_ipset_matchEric W. Biederman1-2/+2
em->net is always set and always available, use it in preference to dev_net(skb->dev). Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2015-06-07bpf: make programs see skb->data == L2 for ingress and egressAlexei Starovoitov2-2/+23
eBPF programs attached to ingress and egress qdiscs see inconsistent skb->data. For ingress L2 header is already pulled, whereas for egress it's present. This is known to program writers which are currently forced to use BPF_LL_OFF workaround. Since programs don't change skb internal pointers it is safe to do pull/push right around invocation of the program and earlier taps and later pt->func() will not be affected. Multiple taps via packet_rcv(), tpacket_rcv() are doing the same trick around run_filter/BPF_PROG_RUN even if skb_shared. This fix finally allows programs to use optimized LD_ABS/IND instructions without BPF_LL_OFF for higher performance. tc ingress + cls_bpf + samples/bpf/tcbpf1_kern.o w/o JIT w/JIT before 20.5 23.6 Mpps after 21.8 26.6 Mpps Old programs with BPF_LL_OFF will still work as-is. We can now undo most of the earlier workaround commit: a166151cbe33 ("bpf: fix bpf helpers to use skb->mac_header relative offsets") Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-04net: Add full IPv6 addresses to flow_keysTom Herbert2-9/+16
This patch adds full IPv6 addresses into flow_keys and uses them as input to the flow hash function. The implementation supports either IPv4 or IPv6 addresses in a union, and selector is used to determine how may words to input to jhash2. We also add flow_get_u32_dst and flow_get_u32_src functions which are used to get a u32 representation of the source and destination addresses. For IPv6, ipv6_addr_hash is called. These functions retain getting the legacy values of src and dst in flow_keys. With this patch, Ethertype and IP protocol are now included in the flow hash input. Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-04net: Get skb hash over flow_keys structureTom Herbert1-0/+2
This patch changes flow hashing to use jhash2 over the flow_keys structure instead just doing jhash_3words over src, dst, and ports. This method will allow us take more input into the hashing function so that we can include full IPv6 addresses, VLAN, flow labels etc. without needing to resort to xor'ing which makes for a poor hash. Acked-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Tom Herbert <tom@herbertland.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-06-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-4/+6
Conflicts: drivers/net/phy/amd-xgbe-phy.c drivers/net/wireless/iwlwifi/Kconfig include/net/mac80211.h iwlwifi/Kconfig and mac80211.h were both trivial overlapping changes. The drivers/net/phy/amd-xgbe-phy.c file got removed in 'net-next' and the bug fix that happened on the 'net' side is already integrated into the rest of the amd-xgbe driver. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-27net_sched: invoke ->attach() after setting dev->qdiscWANG Cong1-4/+6
For mq qdisc, we add per tx queue qdisc to root qdisc for display purpose, however, that happens too early, before the new dev->qdisc is finally set, this causes q->list points to an old root qdisc which is going to be freed right before assigning with a new one. Fix this by moving ->attach() after setting dev->qdisc. For the record, this fixes the following crash: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 975 at lib/list_debug.c:59 __list_del_entry+0x5a/0x98() list_del corruption. prev->next should be ffff8800d1998ae8, but was 6b6b6b6b6b6b6b6b CPU: 1 PID: 975 Comm: tc Not tainted 4.1.0-rc4+ #1019 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000009 ffff8800d73fb928 ffffffff81a44e7f 0000000047574756 ffff8800d73fb978 ffff8800d73fb968 ffffffff810790da ffff8800cfc4cd20 ffffffff814e725b ffff8800d1998ae8 ffffffff82381250 0000000000000000 Call Trace: [<ffffffff81a44e7f>] dump_stack+0x4c/0x65 [<ffffffff810790da>] warn_slowpath_common+0x9c/0xb6 [<ffffffff814e725b>] ? __list_del_entry+0x5a/0x98 [<ffffffff81079162>] warn_slowpath_fmt+0x46/0x48 [<ffffffff81820eb0>] ? dev_graft_qdisc+0x5e/0x6a [<ffffffff814e725b>] __list_del_entry+0x5a/0x98 [<ffffffff814e72a7>] list_del+0xe/0x2d [<ffffffff81822f05>] qdisc_list_del+0x1e/0x20 [<ffffffff81820cd1>] qdisc_destroy+0x30/0xd6 [<ffffffff81822676>] qdisc_graft+0x11d/0x243 [<ffffffff818233c1>] tc_get_qdisc+0x1a6/0x1d4 [<ffffffff810b5eaf>] ? mark_lock+0x2e/0x226 [<ffffffff817ff8f5>] rtnetlink_rcv_msg+0x181/0x194 [<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19 [<ffffffff817ff72e>] ? rtnl_lock+0x17/0x19 [<ffffffff817ff774>] ? __rtnl_unlock+0x17/0x17 [<ffffffff81855dc6>] netlink_rcv_skb+0x4d/0x93 [<ffffffff817ff756>] rtnetlink_rcv+0x26/0x2d [<ffffffff818544b2>] netlink_unicast+0xcb/0x150 [<ffffffff81161db9>] ? might_fault+0x59/0xa9 [<ffffffff81854f78>] netlink_sendmsg+0x4fa/0x51c [<ffffffff817d6e09>] sock_sendmsg_nosec+0x12/0x1d [<ffffffff817d8967>] sock_sendmsg+0x29/0x2e [<ffffffff817d8cf3>] ___sys_sendmsg+0x1b4/0x23a [<ffffffff8100a1b8>] ? native_sched_clock+0x35/0x37 [<ffffffff810a1d83>] ? sched_clock_local+0x12/0x72 [<ffffffff810a1fd4>] ? sched_clock_cpu+0x9e/0xb7 [<ffffffff810def2a>] ? current_kernel_time+0xe/0x32 [<ffffffff810b4bc5>] ? lock_release_holdtime.part.29+0x71/0x7f [<ffffffff810ddebf>] ? read_seqcount_begin.constprop.27+0x5f/0x76 [<ffffffff810b6292>] ? trace_hardirqs_on_caller+0x17d/0x199 [<ffffffff811b14d5>] ? __fget_light+0x50/0x78 [<ffffffff817d9808>] __sys_sendmsg+0x42/0x60 [<ffffffff817d9838>] SyS_sendmsg+0x12/0x1c [<ffffffff81a50e97>] system_call_fastpath+0x12/0x6f ---[ end trace ef29d3fb28e97ae7 ]--- For long term, we probably need to clean up the qdisc_graft() code in case it hides other bugs like this. Fixes: 95dc19299f74 ("pkt_sched: give visibility to mq slave qdiscs") Cc: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-23Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller1-0/+5
Conflicts: drivers/net/ethernet/cadence/macb.c drivers/net/phy/phy.c include/linux/skbuff.h net/ipv4/tcp.c net/switchdev/switchdev.c Switchdev was a case of RTNH_H_{EXTERNAL --> OFFLOAD} renaming overlapping with net-next changes of various sorts. phy.c was a case of two changes, one adding a local variable to a function whilst the second was removing one. tcp.c overlapped a deadlock fix with the addition of new tcp_info statistic values. macb.c involved the addition of two zyncq device entries. skbuff.h involved adding back ipv4_daddr to nf_bridge_info whilst net-next changes put two other existing members of that struct into a union. Signed-off-by: David S. Miller <davem@davemloft.net>
2015-05-21net: sched: fix call_rcu() race on classifier module unloadsDaniel Borkmann1-0/+5
Vijay reported that a loop as simple as ... while true; do tc qdisc add dev foo root handle 1: prio tc filter add dev foo parent 1: u32 match u32 0 0 flowid 1 tc qdisc del dev foo root rmmod cls_u32 done ... will panic the kernel. Moreover, he bisected the change apparently introducing it to 78fd1d0ab072 ("netlink: Re-add locking to netlink_lookup() and seq walker"). The removal of synchronize_net() from the netlink socket triggering the qdisc to be removed, seems to have uncovered an RCU resp. module reference count race from the tc API. Given that RCU conversion was done after e341694e3eb5 ("netlink: Convert netlink_lookup() to use RCU protected hash table") which added the synchronize_net() originally, occasion of hitting the bug was less likely (not impossible though): When qdiscs that i) support attaching classifiers and, ii) have at least one of them attached, get deleted, they invoke tcf_destroy_chain(), and thus call into ->destroy() handler from a classifier module. After RCU conversion, all classifier that have an internal prio list, unlink them and initiate freeing via call_rcu() deferral. Meanhile, tcf_destroy() releases already reference to the tp->ops->owner module before the queued RCU callback handler has been invoked. Subsequent rmmod on the classifier module is then not prevented since all module references are already dropped. By the time, the kernel invokes the RCU callback handler from the module, that function address is then invalid. One way to fix it would be to add an rcu_barrier() to unregister_tcf_proto_ops() to wait for all pending call_rcu()s to complete. synchronize_rcu() is not appropriate as under heavy RCU callback load, registered call_rcu()s could be deferred longer than a grace period. In case we don't have any pending call_rcu()s, the barrier is allowed to return immediately. Since we came here via unregister_tcf_proto_ops(), there are no users of a given classifier anymore. Further nested call_rcu()s pointing into the module space are not being done anywhere. Only cls_bpf_delete_prog() may schedule a work item, to unlock pages eventually, but that is not in the range/context of cls_bpf anymore. Fixes: 25d8c0d55f24 ("net: rcu-ify tcf_proto") Fixes: 9888faefe132 ("net: sched: cls_basic use RCU") Reported-by: Vijay Subramanian <subramanian.vijay@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: Eric Dumazet <edumazet@google.com> Cc: Thomas Graf <tgraf@suug.ch> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Tested-by: Vijay Subramanian <subramanian.vijay@gmail.com> Acked-by: Alexei Starovoitov <ast@plumgrid.com> Acked-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>