kernel-aes67/net/sched/sch_ets.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* net/sched/sch_ets.c Enhanced Transmission Selection scheduler
*
* Description
* -----------
*
* The Enhanced Transmission Selection scheduler is a classful queuing
* discipline that merges functionality of PRIO and DRR qdiscs in one scheduler.
* ETS makes it easy to configure a set of strict and bandwidth-sharing bands to
* implement the transmission selection described in 802.1Qaz.
*
* Although ETS is technically classful, it's not possible to add and remove
* classes at will. Instead one specifies number of classes, how many are
* PRIO-like and how many DRR-like, and quanta for the latter.
*
* Algorithm
* ---------
*
* The strict classes, if any, are tried for traffic first: first band 0, if it
* has no traffic then band 1, etc.
*
* When there is no traffic in any of the strict queues, the bandwidth-sharing
* ones are tried next. Each band is assigned a deficit counter, initialized to
* "quantum" of that band. ETS maintains a list of active bandwidth-sharing
* bands whose qdiscs are non-empty. A packet is dequeued from the band at the
* head of the list if the packet size is smaller or equal to the deficit
* counter. If the counter is too small, it is increased by "quantum" and the
* scheduler moves on to the next band in the active list.
*/
#include <linux/module.h>
#include <net/gen_stats.h>
#include <net/netlink.h>
#include <net/pkt_cls.h>
#include <net/pkt_sched.h>
#include <net/sch_generic.h>
struct ets_class {
struct list_head alist; /* In struct ets_sched.active. */
struct Qdisc *qdisc;
u32 quantum;
u32 deficit;
struct gnet_stats_basic_sync bstats;
struct gnet_stats_queue qstats;
};
struct ets_sched {
struct list_head active;
struct tcf_proto __rcu *filter_list;
struct tcf_block *block;
unsigned int nbands;
unsigned int nstrict;
u8 prio2band[TC_PRIO_MAX + 1];
struct ets_class classes[TCQ_ETS_MAX_BANDS];
};
static const struct nla_policy ets_policy[TCA_ETS_MAX + 1] = {
[TCA_ETS_NBANDS] = { .type = NLA_U8 },
[TCA_ETS_NSTRICT] = { .type = NLA_U8 },
[TCA_ETS_QUANTA] = { .type = NLA_NESTED },
[TCA_ETS_PRIOMAP] = { .type = NLA_NESTED },
};
static const struct nla_policy ets_priomap_policy[TCA_ETS_MAX + 1] = {
[TCA_ETS_PRIOMAP_BAND] = { .type = NLA_U8 },
};
static const struct nla_policy ets_quanta_policy[TCA_ETS_MAX + 1] = {
[TCA_ETS_QUANTA_BAND] = { .type = NLA_U32 },
};
static const struct nla_policy ets_class_policy[TCA_ETS_MAX + 1] = {
[TCA_ETS_QUANTA_BAND] = { .type = NLA_U32 },
};
static int ets_quantum_parse(struct Qdisc *sch, const struct nlattr *attr,
unsigned int *quantum,
struct netlink_ext_ack *extack)
{
*quantum = nla_get_u32(attr);
if (!*quantum) {
NL_SET_ERR_MSG(extack, "ETS quantum cannot be zero");
return -EINVAL;
}
return 0;
}
static struct ets_class *
ets_class_from_arg(struct Qdisc *sch, unsigned long arg)
{
struct ets_sched *q = qdisc_priv(sch);
return &q->classes[arg - 1];
}
static u32 ets_class_id(struct Qdisc *sch, const struct ets_class *cl)
{
struct ets_sched *q = qdisc_priv(sch);
int band = cl - q->classes;
return TC_H_MAKE(sch->handle, band + 1);
}
static void ets_offload_change(struct Qdisc *sch)
{
struct net_device *dev = qdisc_dev(sch);
struct ets_sched *q = qdisc_priv(sch);
struct tc_ets_qopt_offload qopt;
unsigned int w_psum_prev = 0;
unsigned int q_psum = 0;
unsigned int q_sum = 0;
unsigned int quantum;
unsigned int w_psum;
unsigned int weight;
unsigned int i;
if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
return;
qopt.command = TC_ETS_REPLACE;
qopt.handle = sch->handle;
qopt.parent = sch->parent;
qopt.replace_params.bands = q->nbands;
qopt.replace_params.qstats = &sch->qstats;
memcpy(&qopt.replace_params.priomap,
q->prio2band, sizeof(q->prio2band));
for (i = 0; i < q->nbands; i++)
q_sum += q->classes[i].quantum;
for (i = 0; i < q->nbands; i++) {
quantum = q->classes[i].quantum;
q_psum += quantum;
w_psum = quantum ? q_psum * 100 / q_sum : 0;
weight = w_psum - w_psum_prev;
w_psum_prev = w_psum;
qopt.replace_params.quanta[i] = quantum;
qopt.replace_params.weights[i] = weight;
}
dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETS, &qopt);
}
static void ets_offload_destroy(struct Qdisc *sch)
{
struct net_device *dev = qdisc_dev(sch);
struct tc_ets_qopt_offload qopt;
if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
return;
qopt.command = TC_ETS_DESTROY;
qopt.handle = sch->handle;
qopt.parent = sch->parent;
dev->netdev_ops->ndo_setup_tc(dev, TC_SETUP_QDISC_ETS, &qopt);
}
static void ets_offload_graft(struct Qdisc *sch, struct Qdisc *new,
struct Qdisc *old, unsigned long arg,
struct netlink_ext_ack *extack)
{
struct net_device *dev = qdisc_dev(sch);
struct tc_ets_qopt_offload qopt;
qopt.command = TC_ETS_GRAFT;
qopt.handle = sch->handle;
qopt.parent = sch->parent;
qopt.graft_params.band = arg - 1;
qopt.graft_params.child_handle = new->handle;
qdisc_offload_graft_helper(dev, sch, new, old, TC_SETUP_QDISC_ETS,
&qopt, extack);
}
static int ets_offload_dump(struct Qdisc *sch)
{
struct tc_ets_qopt_offload qopt;
qopt.command = TC_ETS_STATS;
qopt.handle = sch->handle;
qopt.parent = sch->parent;
qopt.stats.bstats = &sch->bstats;
qopt.stats.qstats = &sch->qstats;
return qdisc_offload_dump_helper(sch, TC_SETUP_QDISC_ETS, &qopt);
}
static bool ets_class_is_strict(struct ets_sched *q, const struct ets_class *cl)
{
unsigned int band = cl - q->classes;
return band < q->nstrict;
}
static int ets_class_change(struct Qdisc *sch, u32 classid, u32 parentid,
struct nlattr **tca, unsigned long *arg,
struct netlink_ext_ack *extack)
{
struct ets_class *cl = ets_class_from_arg(sch, *arg);
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_ETS_MAX + 1];
unsigned int quantum;
int err;
/* Classes can be added and removed only through Qdisc_ops.change
* interface.
*/
if (!cl) {
NL_SET_ERR_MSG(extack, "Fine-grained class addition and removal is not supported");
return -EOPNOTSUPP;
}
if (!opt) {
NL_SET_ERR_MSG(extack, "ETS options are required for this operation");
return -EINVAL;
}
err = nla_parse_nested(tb, TCA_ETS_MAX, opt, ets_class_policy, extack);
if (err < 0)
return err;
if (!tb[TCA_ETS_QUANTA_BAND])
/* Nothing to configure. */
return 0;
if (ets_class_is_strict(q, cl)) {
NL_SET_ERR_MSG(extack, "Strict bands do not have a configurable quantum");
return -EINVAL;
}
err = ets_quantum_parse(sch, tb[TCA_ETS_QUANTA_BAND], &quantum,
extack);
if (err)
return err;
sch_tree_lock(sch);
cl->quantum = quantum;
sch_tree_unlock(sch);
ets_offload_change(sch);
return 0;
}
static int ets_class_graft(struct Qdisc *sch, unsigned long arg,
struct Qdisc *new, struct Qdisc **old,
struct netlink_ext_ack *extack)
{
struct ets_class *cl = ets_class_from_arg(sch, arg);
if (!new) {
new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
ets_class_id(sch, cl), NULL);
if (!new)
new = &noop_qdisc;
else
qdisc_hash_add(new, true);
}
*old = qdisc_replace(sch, new, &cl->qdisc);
ets_offload_graft(sch, new, *old, arg, extack);
return 0;
}
static struct Qdisc *ets_class_leaf(struct Qdisc *sch, unsigned long arg)
{
struct ets_class *cl = ets_class_from_arg(sch, arg);
return cl->qdisc;
}
static unsigned long ets_class_find(struct Qdisc *sch, u32 classid)
{
unsigned long band = TC_H_MIN(classid);
struct ets_sched *q = qdisc_priv(sch);
if (band - 1 >= q->nbands)
return 0;
return band;
}
static void ets_class_qlen_notify(struct Qdisc *sch, unsigned long arg)
{
struct ets_class *cl = ets_class_from_arg(sch, arg);
struct ets_sched *q = qdisc_priv(sch);
/* We get notified about zero-length child Qdiscs as well if they are
* offloaded. Those aren't on the active list though, so don't attempt
* to remove them.
*/
if (!ets_class_is_strict(q, cl) && sch->q.qlen)
list_del(&cl->alist);
}
static int ets_class_dump(struct Qdisc *sch, unsigned long arg,
struct sk_buff *skb, struct tcmsg *tcm)
{
struct ets_class *cl = ets_class_from_arg(sch, arg);
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *nest;
tcm->tcm_parent = TC_H_ROOT;
tcm->tcm_handle = ets_class_id(sch, cl);
tcm->tcm_info = cl->qdisc->handle;
nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (!nest)
goto nla_put_failure;
if (!ets_class_is_strict(q, cl)) {
if (nla_put_u32(skb, TCA_ETS_QUANTA_BAND, cl->quantum))
goto nla_put_failure;
}
return nla_nest_end(skb, nest);
nla_put_failure:
nla_nest_cancel(skb, nest);
return -EMSGSIZE;
}
static int ets_class_dump_stats(struct Qdisc *sch, unsigned long arg,
struct gnet_dump *d)
{
struct ets_class *cl = ets_class_from_arg(sch, arg);
struct Qdisc *cl_q = cl->qdisc;
net: sched: Remove Qdisc::running sequence counter The Qdisc::running sequence counter has two uses: 1. Reliably reading qdisc's tc statistics while the qdisc is running (a seqcount read/retry loop at gnet_stats_add_basic()). 2. As a flag, indicating whether the qdisc in question is running (without any retry loops). For the first usage, the Qdisc::running sequence counter write section, qdisc_run_begin() => qdisc_run_end(), covers a much wider area than what is actually needed: the raw qdisc's bstats update. A u64_stats sync point was thus introduced (in previous commits) inside the bstats structure itself. A local u64_stats write section is then started and stopped for the bstats updates. Use that u64_stats sync point mechanism for the bstats read/retry loop at gnet_stats_add_basic(). For the second qdisc->running usage, a __QDISC_STATE_RUNNING bit flag, accessed with atomic bitops, is sufficient. Using a bit flag instead of a sequence counter at qdisc_run_begin/end() and qdisc_is_running() leads to the SMP barriers implicitly added through raw_read_seqcount() and write_seqcount_begin/end() getting removed. All call sites have been surveyed though, and no required ordering was identified. Now that the qdisc->running sequence counter is no longer used, remove it. Note, using u64_stats implies no sequence counter protection for 64-bit architectures. This can lead to the qdisc tc statistics "packets" vs. "bytes" values getting out of sync on rare occasions. The individual values will still be valid. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-10-16 04:49:10 -04:00
if (gnet_stats_copy_basic(d, NULL, &cl_q->bstats, true) < 0 ||
qdisc_qstats_copy(d, cl_q) < 0)
return -1;
return 0;
}
static void ets_qdisc_walk(struct Qdisc *sch, struct qdisc_walker *arg)
{
struct ets_sched *q = qdisc_priv(sch);
int i;
if (arg->stop)
return;
for (i = 0; i < q->nbands; i++) {
if (!tc_qdisc_stats_dump(sch, i + 1, arg))
break;
}
}
static struct tcf_block *
ets_qdisc_tcf_block(struct Qdisc *sch, unsigned long cl,
struct netlink_ext_ack *extack)
{
struct ets_sched *q = qdisc_priv(sch);
if (cl) {
NL_SET_ERR_MSG(extack, "ETS classid must be zero");
return NULL;
}
return q->block;
}
static unsigned long ets_qdisc_bind_tcf(struct Qdisc *sch, unsigned long parent,
u32 classid)
{
return ets_class_find(sch, classid);
}
static void ets_qdisc_unbind_tcf(struct Qdisc *sch, unsigned long arg)
{
}
static struct ets_class *ets_classify(struct sk_buff *skb, struct Qdisc *sch,
int *qerr)
{
struct ets_sched *q = qdisc_priv(sch);
u32 band = skb->priority;
struct tcf_result res;
struct tcf_proto *fl;
int err;
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
if (TC_H_MAJ(skb->priority) != sch->handle) {
fl = rcu_dereference_bh(q->filter_list);
err = tcf_classify(skb, NULL, fl, &res, false);
#ifdef CONFIG_NET_CLS_ACT
switch (err) {
case TC_ACT_STOLEN:
case TC_ACT_QUEUED:
case TC_ACT_TRAP:
*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
fallthrough;
case TC_ACT_SHOT:
return NULL;
}
#endif
if (!fl || err < 0) {
if (TC_H_MAJ(band))
band = 0;
return &q->classes[q->prio2band[band & TC_PRIO_MAX]];
}
band = res.classid;
}
band = TC_H_MIN(band) - 1;
if (band >= q->nbands)
return &q->classes[q->prio2band[0]];
return &q->classes[band];
}
static int ets_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
struct sk_buff **to_free)
{
unsigned int len = qdisc_pkt_len(skb);
struct ets_sched *q = qdisc_priv(sch);
struct ets_class *cl;
int err = 0;
bool first;
cl = ets_classify(skb, sch, &err);
if (!cl) {
if (err & __NET_XMIT_BYPASS)
qdisc_qstats_drop(sch);
__qdisc_drop(skb, to_free);
return err;
}
first = !cl->qdisc->q.qlen;
err = qdisc_enqueue(skb, cl->qdisc, to_free);
if (unlikely(err != NET_XMIT_SUCCESS)) {
if (net_xmit_drop_count(err)) {
cl->qstats.drops++;
qdisc_qstats_drop(sch);
}
return err;
}
if (first && !ets_class_is_strict(q, cl)) {
list_add_tail(&cl->alist, &q->active);
cl->deficit = cl->quantum;
}
sch->qstats.backlog += len;
sch->q.qlen++;
return err;
}
static struct sk_buff *
ets_qdisc_dequeue_skb(struct Qdisc *sch, struct sk_buff *skb)
{
qdisc_bstats_update(sch, skb);
qdisc_qstats_backlog_dec(sch, skb);
sch->q.qlen--;
return skb;
}
static struct sk_buff *ets_qdisc_dequeue(struct Qdisc *sch)
{
struct ets_sched *q = qdisc_priv(sch);
struct ets_class *cl;
struct sk_buff *skb;
unsigned int band;
unsigned int len;
while (1) {
for (band = 0; band < q->nstrict; band++) {
cl = &q->classes[band];
skb = qdisc_dequeue_peeked(cl->qdisc);
if (skb)
return ets_qdisc_dequeue_skb(sch, skb);
}
if (list_empty(&q->active))
goto out;
cl = list_first_entry(&q->active, struct ets_class, alist);
skb = cl->qdisc->ops->peek(cl->qdisc);
if (!skb) {
qdisc_warn_nonwc(__func__, cl->qdisc);
goto out;
}
len = qdisc_pkt_len(skb);
if (len <= cl->deficit) {
cl->deficit -= len;
skb = qdisc_dequeue_peeked(cl->qdisc);
if (unlikely(!skb))
goto out;
if (cl->qdisc->q.qlen == 0)
list_del(&cl->alist);
return ets_qdisc_dequeue_skb(sch, skb);
}
cl->deficit += cl->quantum;
list_move_tail(&cl->alist, &q->active);
}
out:
return NULL;
}
static int ets_qdisc_priomap_parse(struct nlattr *priomap_attr,
unsigned int nbands, u8 *priomap,
struct netlink_ext_ack *extack)
{
const struct nlattr *attr;
int prio = 0;
u8 band;
int rem;
int err;
err = __nla_validate_nested(priomap_attr, TCA_ETS_MAX,
ets_priomap_policy, NL_VALIDATE_STRICT,
extack);
if (err)
return err;
nla_for_each_nested(attr, priomap_attr, rem) {
switch (nla_type(attr)) {
case TCA_ETS_PRIOMAP_BAND:
if (prio > TC_PRIO_MAX) {
NL_SET_ERR_MSG_MOD(extack, "Too many priorities in ETS priomap");
return -EINVAL;
}
band = nla_get_u8(attr);
if (band >= nbands) {
NL_SET_ERR_MSG_MOD(extack, "Invalid band number in ETS priomap");
return -EINVAL;
}
priomap[prio++] = band;
break;
default:
WARN_ON_ONCE(1); /* Validate should have caught this. */
return -EINVAL;
}
}
return 0;
}
static int ets_qdisc_quanta_parse(struct Qdisc *sch, struct nlattr *quanta_attr,
unsigned int nbands, unsigned int nstrict,
unsigned int *quanta,
struct netlink_ext_ack *extack)
{
const struct nlattr *attr;
int band = nstrict;
int rem;
int err;
err = __nla_validate_nested(quanta_attr, TCA_ETS_MAX,
ets_quanta_policy, NL_VALIDATE_STRICT,
extack);
if (err < 0)
return err;
nla_for_each_nested(attr, quanta_attr, rem) {
switch (nla_type(attr)) {
case TCA_ETS_QUANTA_BAND:
if (band >= nbands) {
NL_SET_ERR_MSG_MOD(extack, "ETS quanta has more values than bands");
return -EINVAL;
}
err = ets_quantum_parse(sch, attr, &quanta[band++],
extack);
if (err)
return err;
break;
default:
WARN_ON_ONCE(1); /* Validate should have caught this. */
return -EINVAL;
}
}
return 0;
}
static int ets_qdisc_change(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
unsigned int quanta[TCQ_ETS_MAX_BANDS] = {0};
struct Qdisc *queues[TCQ_ETS_MAX_BANDS];
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *tb[TCA_ETS_MAX + 1];
unsigned int oldbands = q->nbands;
u8 priomap[TC_PRIO_MAX + 1];
unsigned int nstrict = 0;
unsigned int nbands;
unsigned int i;
int err;
err = nla_parse_nested(tb, TCA_ETS_MAX, opt, ets_policy, extack);
if (err < 0)
return err;
if (!tb[TCA_ETS_NBANDS]) {
NL_SET_ERR_MSG_MOD(extack, "Number of bands is a required argument");
return -EINVAL;
}
nbands = nla_get_u8(tb[TCA_ETS_NBANDS]);
if (nbands < 1 || nbands > TCQ_ETS_MAX_BANDS) {
NL_SET_ERR_MSG_MOD(extack, "Invalid number of bands");
return -EINVAL;
}
/* Unless overridden, traffic goes to the last band. */
memset(priomap, nbands - 1, sizeof(priomap));
if (tb[TCA_ETS_NSTRICT]) {
nstrict = nla_get_u8(tb[TCA_ETS_NSTRICT]);
if (nstrict > nbands) {
NL_SET_ERR_MSG_MOD(extack, "Invalid number of strict bands");
return -EINVAL;
}
}
if (tb[TCA_ETS_PRIOMAP]) {
err = ets_qdisc_priomap_parse(tb[TCA_ETS_PRIOMAP],
nbands, priomap, extack);
if (err)
return err;
}
if (tb[TCA_ETS_QUANTA]) {
err = ets_qdisc_quanta_parse(sch, tb[TCA_ETS_QUANTA],
nbands, nstrict, quanta, extack);
if (err)
return err;
}
/* If there are more bands than strict + quanta provided, the remaining
* ones are ETS with quantum of MTU. Initialize the missing values here.
*/
for (i = nstrict; i < nbands; i++) {
if (!quanta[i])
quanta[i] = psched_mtu(qdisc_dev(sch));
}
/* Before commit, make sure we can allocate all new qdiscs */
for (i = oldbands; i < nbands; i++) {
queues[i] = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
ets_class_id(sch, &q->classes[i]),
extack);
if (!queues[i]) {
while (i > oldbands)
qdisc_put(queues[--i]);
return -ENOMEM;
}
}
sch_tree_lock(sch);
q->nbands = nbands;
net/sched: ets: fix crash when flipping from 'strict' to 'quantum' While running kselftests, Hangbin observed that sch_ets.sh often crashes, and splats like the following one are seen in the output of 'dmesg': BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 159f12067 P4D 159f12067 PUD 159f13067 PMD 0 Oops: 0000 [#1] SMP NOPTI CPU: 2 PID: 921 Comm: tc Not tainted 5.14.0-rc6+ #458 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:__list_del_entry_valid+0x2d/0x50 Code: 48 8b 57 08 48 b9 00 01 00 00 00 00 ad de 48 39 c8 0f 84 ac 6e 5b 00 48 b9 22 01 00 00 00 00 ad de 48 39 ca 0f 84 cf 6e 5b 00 <48> 8b 32 48 39 fe 0f 85 af 6e 5b 00 48 8b 50 08 48 39 f2 0f 85 94 RSP: 0018:ffffb2da005c3890 EFLAGS: 00010217 RAX: 0000000000000000 RBX: ffff9073ba23f800 RCX: dead000000000122 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff9073ba23fbc8 RBP: ffff9073ba23f890 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000001 R12: dead000000000100 R13: ffff9073ba23fb00 R14: 0000000000000002 R15: 0000000000000002 FS: 00007f93e5564e40(0000) GS:ffff9073bba00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000014ad34000 CR4: 0000000000350ee0 Call Trace: ets_qdisc_reset+0x6e/0x100 [sch_ets] qdisc_reset+0x49/0x1d0 tbf_reset+0x15/0x60 [sch_tbf] qdisc_reset+0x49/0x1d0 dev_reset_queue.constprop.42+0x2f/0x90 dev_deactivate_many+0x1d3/0x3d0 dev_deactivate+0x56/0x90 qdisc_graft+0x47e/0x5a0 tc_get_qdisc+0x1db/0x3e0 rtnetlink_rcv_msg+0x164/0x4c0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1a5/0x280 netlink_sendmsg+0x242/0x480 sock_sendmsg+0x5b/0x60 ____sys_sendmsg+0x1f2/0x260 ___sys_sendmsg+0x7c/0xc0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f93e44b8338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 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 41 54 41 89 d4 55 RSP: 002b:00007ffc0db737a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000061255c06 RCX: 00007f93e44b8338 RDX: 0000000000000000 RSI: 00007ffc0db73810 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000687880 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt iTCO_vendor_support intel_rapl_msr intel_rapl_common joydev i2c_i801 pcspkr i2c_smbus lpc_ich virtio_balloon ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel ahci libahci ghash_clmulni_intel libata serio_raw virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000000 When the change() function decreases the value of 'nstrict', we must take into account that packets might be already enqueued on a class that flips from 'strict' to 'quantum': otherwise that class will not be added to the bandwidth-sharing list. Then, a call to ets_qdisc_reset() will attempt to do list_del(&alist) with 'alist' filled with zero, hence the NULL pointer dereference. For classes flipping from 'strict' to 'quantum', initialize an empty list and eventually add it to the bandwidth-sharing list, if there are packets already enqueued. In this way, the kernel will: a) prevent crashing as described above. b) avoid retaining the backlog packets (for an arbitrarily long time) in case no packet is enqueued after a change from 'strict' to 'quantum'. Reported-by: Hangbin Liu <liuhangbin@gmail.com> Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-08-24 18:33:48 -04:00
for (i = nstrict; i < q->nstrict; i++) {
if (q->classes[i].qdisc->q.qlen) {
list_add_tail(&q->classes[i].alist, &q->active);
q->classes[i].deficit = quanta[i];
}
}
net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets_qdisc_change(). As a consequence, it's possible to see a NULL dereference crash, caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [sch_ets] Code: c5 01 41 39 ad e4 02 00 00 0f 87 18 ff ff ff 49 8b 85 c0 02 00 00 49 39 c4 0f 84 ba 00 00 00 49 8b ad c0 02 00 00 48 8b 7d 10 <48> 8b 47 18 48 8b 40 38 0f ae e8 ff d0 48 89 c3 48 85 c0 0f 84 9d RSP: 0000:ffffbb36c0b5fdd8 EFLAGS: 00010287 RAX: ffff956678efed30 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff9b938dc9 RDI: 0000000000000000 RBP: ffff956678efed30 R08: e2f3207fe360129c R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff956678efeac0 R13: ffff956678efe800 R14: ffff956611545000 R15: ffff95667ac8f100 FS: 00007f2aa9120740(0000) GS:ffff95667b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000011070c000 CR4: 0000000000350ee0 Call Trace: <TASK> qdisc_peek_dequeued+0x29/0x70 [sch_ets] tbf_dequeue+0x22/0x260 [sch_tbf] __qdisc_run+0x7f/0x630 net_tx_action+0x290/0x4c0 __do_softirq+0xee/0x4f8 irq_exit_rcu+0xf4/0x130 sysvec_apic_timer_interrupt+0x52/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0033:0x7f2aa7fc9ad4 Code: b9 ff ff 48 8b 54 24 18 48 83 c4 08 48 89 ee 48 89 df 5b 5d e9 ed fc ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa <53> 48 83 ec 10 48 8b 05 10 64 33 00 48 8b 00 48 85 c0 0f 85 84 00 RSP: 002b:00007ffe5d33fab8 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000561f72c31460 RCX: 0000561f72c31720 RDX: 0000000000000002 RSI: 0000561f72c31722 RDI: 0000561f72c31720 RBP: 000000000000002a R08: 00007ffe5d33fa40 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 0000561f7187e380 R13: 0000000000000000 R14: 0000000000000000 R15: 0000561f72c31460 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt intel_rapl_msr iTCO_vendor_support intel_rapl_common joydev virtio_balloon lpc_ich i2c_i801 i2c_smbus pcspkr ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel ahci libahci ghash_clmulni_intel serio_raw libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000018 Ensuring that 'alist' was never zeroed [1] was not sufficient, we need to remove from the active list those elements that are no more SP nor DRR. [1] https://lore.kernel.org/netdev/60d274838bf09777f0371253416e8af71360bc08.1633609148.git.dcaratti@redhat.com/ v3: fix race between ets_qdisc_change() and ets_qdisc_dequeue() delisting DRR classes beyond 'nbands' in ets_qdisc_change() with the qdisc lock acquired, thanks to Cong Wang. v2: when a NULL qdisc is found in the DRR active list, try to dequeue skb from the next list item. Reported-by: Hangbin Liu <liuhangbin@gmail.com> Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Link: https://lore.kernel.org/r/7a5c496eed2d62241620bdbb83eb03fb9d571c99.1637762721.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-24 11:14:40 -05:00
for (i = q->nbands; i < oldbands; i++) {
net/sched: sch_ets: don't remove idle classes from the round-robin list Shuang reported that the following script: 1) tc qdisc add dev ddd0 handle 10: parent 1: ets bands 8 strict 4 priomap 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 2) mausezahn ddd0 -A 10.10.10.1 -B 10.10.10.2 -c 0 -a own -b 00:c1:a0:c1:a0:00 -t udp & 3) tc qdisc change dev ddd0 handle 10: ets bands 4 strict 2 quanta 2500 2500 priomap 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 crashes systematically when line 2) is commented: list_del corruption, ffff8e028404bd30->next is LIST_POISON1 (dead000000000100) ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:47! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 954 Comm: tc Not tainted 5.16.0-rc4+ #478 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000682f48 CR3: 00000001058be000 CR4: 0000000000350ef0 Call Trace: <TASK> ets_qdisc_change+0x58b/0xa70 [sch_ets] tc_modify_qdisc+0x323/0x880 rtnetlink_rcv_msg+0x169/0x4a0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1a5/0x280 netlink_sendmsg+0x257/0x4d0 sock_sendmsg+0x5b/0x60 ____sys_sendmsg+0x1f2/0x260 ___sys_sendmsg+0x7c/0xc0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efdc8031338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 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 41 54 41 89 d4 55 RSP: 002b:00007ffdf1ce9828 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000061b37a97 RCX: 00007efdc8031338 RDX: 0000000000000000 RSI: 00007ffdf1ce9890 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000078a940 R10: 000000000000000c R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000688880 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt iTCO_vendor_support intel_rapl_msr intel_rapl_common joydev pcspkr i2c_i801 virtio_balloon i2c_smbus lpc_ich ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel serio_raw ghash_clmulni_intel ahci libahci libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod [last unloaded: sch_ets] ---[ end trace f35878d1912655c2 ]--- RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000682f48 CR3: 00000001058be000 CR4: 0000000000350ef0 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: 0x4e00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- we can remove 'q->classes[i].alist' only if DRR class 'i' was part of the active list. In the ETS scheduler DRR classes belong to that list only if the queue length is greater than zero: we need to test for non-zero value of 'q->classes[i].qdisc->q.qlen' before removing from the list, similarly to what has been done elsewhere in the ETS code. Fixes: de6d25924c2a ("net/sched: sch_ets: don't peek at classes beyond 'nbands'") Reported-by: Shuang Li <shuali@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-12-10 11:42:47 -05:00
if (i >= q->nstrict && q->classes[i].qdisc->q.qlen)
net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets_qdisc_change(). As a consequence, it's possible to see a NULL dereference crash, caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [sch_ets] Code: c5 01 41 39 ad e4 02 00 00 0f 87 18 ff ff ff 49 8b 85 c0 02 00 00 49 39 c4 0f 84 ba 00 00 00 49 8b ad c0 02 00 00 48 8b 7d 10 <48> 8b 47 18 48 8b 40 38 0f ae e8 ff d0 48 89 c3 48 85 c0 0f 84 9d RSP: 0000:ffffbb36c0b5fdd8 EFLAGS: 00010287 RAX: ffff956678efed30 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff9b938dc9 RDI: 0000000000000000 RBP: ffff956678efed30 R08: e2f3207fe360129c R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff956678efeac0 R13: ffff956678efe800 R14: ffff956611545000 R15: ffff95667ac8f100 FS: 00007f2aa9120740(0000) GS:ffff95667b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000011070c000 CR4: 0000000000350ee0 Call Trace: <TASK> qdisc_peek_dequeued+0x29/0x70 [sch_ets] tbf_dequeue+0x22/0x260 [sch_tbf] __qdisc_run+0x7f/0x630 net_tx_action+0x290/0x4c0 __do_softirq+0xee/0x4f8 irq_exit_rcu+0xf4/0x130 sysvec_apic_timer_interrupt+0x52/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0033:0x7f2aa7fc9ad4 Code: b9 ff ff 48 8b 54 24 18 48 83 c4 08 48 89 ee 48 89 df 5b 5d e9 ed fc ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa <53> 48 83 ec 10 48 8b 05 10 64 33 00 48 8b 00 48 85 c0 0f 85 84 00 RSP: 002b:00007ffe5d33fab8 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000561f72c31460 RCX: 0000561f72c31720 RDX: 0000000000000002 RSI: 0000561f72c31722 RDI: 0000561f72c31720 RBP: 000000000000002a R08: 00007ffe5d33fa40 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 0000561f7187e380 R13: 0000000000000000 R14: 0000000000000000 R15: 0000561f72c31460 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt intel_rapl_msr iTCO_vendor_support intel_rapl_common joydev virtio_balloon lpc_ich i2c_i801 i2c_smbus pcspkr ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel ahci libahci ghash_clmulni_intel serio_raw libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000018 Ensuring that 'alist' was never zeroed [1] was not sufficient, we need to remove from the active list those elements that are no more SP nor DRR. [1] https://lore.kernel.org/netdev/60d274838bf09777f0371253416e8af71360bc08.1633609148.git.dcaratti@redhat.com/ v3: fix race between ets_qdisc_change() and ets_qdisc_dequeue() delisting DRR classes beyond 'nbands' in ets_qdisc_change() with the qdisc lock acquired, thanks to Cong Wang. v2: when a NULL qdisc is found in the DRR active list, try to dequeue skb from the next list item. Reported-by: Hangbin Liu <liuhangbin@gmail.com> Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Link: https://lore.kernel.org/r/7a5c496eed2d62241620bdbb83eb03fb9d571c99.1637762721.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-24 11:14:40 -05:00
list_del(&q->classes[i].alist);
net/sched: sch_ets: don't remove idle classes from the round-robin list Shuang reported that the following script: 1) tc qdisc add dev ddd0 handle 10: parent 1: ets bands 8 strict 4 priomap 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 2) mausezahn ddd0 -A 10.10.10.1 -B 10.10.10.2 -c 0 -a own -b 00:c1:a0:c1:a0:00 -t udp & 3) tc qdisc change dev ddd0 handle 10: ets bands 4 strict 2 quanta 2500 2500 priomap 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 crashes systematically when line 2) is commented: list_del corruption, ffff8e028404bd30->next is LIST_POISON1 (dead000000000100) ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:47! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 954 Comm: tc Not tainted 5.16.0-rc4+ #478 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000682f48 CR3: 00000001058be000 CR4: 0000000000350ef0 Call Trace: <TASK> ets_qdisc_change+0x58b/0xa70 [sch_ets] tc_modify_qdisc+0x323/0x880 rtnetlink_rcv_msg+0x169/0x4a0 netlink_rcv_skb+0x50/0x100 netlink_unicast+0x1a5/0x280 netlink_sendmsg+0x257/0x4d0 sock_sendmsg+0x5b/0x60 ____sys_sendmsg+0x1f2/0x260 ___sys_sendmsg+0x7c/0xc0 __sys_sendmsg+0x57/0xa0 do_syscall_64+0x3a/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7efdc8031338 Code: 89 02 48 c7 c0 ff ff ff ff eb b5 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 25 43 2c 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 41 54 41 89 d4 55 RSP: 002b:00007ffdf1ce9828 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 0000000061b37a97 RCX: 00007efdc8031338 RDX: 0000000000000000 RSI: 00007ffdf1ce9890 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000001 R09: 000000000078a940 R10: 000000000000000c R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000688880 R14: 0000000000000000 R15: 0000000000000000 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt iTCO_vendor_support intel_rapl_msr intel_rapl_common joydev pcspkr i2c_i801 virtio_balloon i2c_smbus lpc_ich ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel serio_raw ghash_clmulni_intel ahci libahci libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod [last unloaded: sch_ets] ---[ end trace f35878d1912655c2 ]--- RIP: 0010:__list_del_entry_valid.cold.1+0x12/0x47 Code: fe ff 0f 0b 48 89 c1 4c 89 c6 48 c7 c7 08 42 1b 87 e8 1d c5 fe ff 0f 0b 48 89 fe 48 89 c2 48 c7 c7 98 42 1b 87 e8 09 c5 fe ff <0f> 0b 48 c7 c7 48 43 1b 87 e8 fb c4 fe ff 0f 0b 48 89 f2 48 89 fe RSP: 0018:ffffae46807a3888 EFLAGS: 00010246 RAX: 000000000000004e RBX: 0000000000000007 RCX: 0000000000000202 RDX: 0000000000000000 RSI: ffffffff871ac536 RDI: 00000000ffffffff RBP: ffffae46807a3a10 R08: 0000000000000000 R09: c0000000ffff7fff R10: 0000000000000001 R11: ffffae46807a36a8 R12: ffff8e028404b800 R13: ffff8e028404bd30 R14: dead000000000100 R15: ffff8e02fafa2400 FS: 00007efdc92e4480(0000) GS:ffff8e02fb600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000682f48 CR3: 00000001058be000 CR4: 0000000000350ef0 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: 0x4e00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]--- we can remove 'q->classes[i].alist' only if DRR class 'i' was part of the active list. In the ETS scheduler DRR classes belong to that list only if the queue length is greater than zero: we need to test for non-zero value of 'q->classes[i].qdisc->q.qlen' before removing from the list, similarly to what has been done elsewhere in the ETS code. Fixes: de6d25924c2a ("net/sched: sch_ets: don't peek at classes beyond 'nbands'") Reported-by: Shuang Li <shuali@redhat.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2021-12-10 11:42:47 -05:00
qdisc_tree_flush_backlog(q->classes[i].qdisc);
net/sched: sch_ets: don't peek at classes beyond 'nbands' when the number of DRR classes decreases, the round-robin active list can contain elements that have already been freed in ets_qdisc_change(). As a consequence, it's possible to see a NULL dereference crash, caused by the attempt to call cl->qdisc->ops->peek(cl->qdisc) when cl->qdisc is NULL: BUG: kernel NULL pointer dereference, address: 0000000000000018 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 910 Comm: mausezahn Not tainted 5.16.0-rc1+ #475 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 RIP: 0010:ets_qdisc_dequeue+0x129/0x2c0 [sch_ets] Code: c5 01 41 39 ad e4 02 00 00 0f 87 18 ff ff ff 49 8b 85 c0 02 00 00 49 39 c4 0f 84 ba 00 00 00 49 8b ad c0 02 00 00 48 8b 7d 10 <48> 8b 47 18 48 8b 40 38 0f ae e8 ff d0 48 89 c3 48 85 c0 0f 84 9d RSP: 0000:ffffbb36c0b5fdd8 EFLAGS: 00010287 RAX: ffff956678efed30 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000002 RSI: ffffffff9b938dc9 RDI: 0000000000000000 RBP: ffff956678efed30 R08: e2f3207fe360129c R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff956678efeac0 R13: ffff956678efe800 R14: ffff956611545000 R15: ffff95667ac8f100 FS: 00007f2aa9120740(0000) GS:ffff95667b800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 000000011070c000 CR4: 0000000000350ee0 Call Trace: <TASK> qdisc_peek_dequeued+0x29/0x70 [sch_ets] tbf_dequeue+0x22/0x260 [sch_tbf] __qdisc_run+0x7f/0x630 net_tx_action+0x290/0x4c0 __do_softirq+0xee/0x4f8 irq_exit_rcu+0xf4/0x130 sysvec_apic_timer_interrupt+0x52/0xc0 asm_sysvec_apic_timer_interrupt+0x12/0x20 RIP: 0033:0x7f2aa7fc9ad4 Code: b9 ff ff 48 8b 54 24 18 48 83 c4 08 48 89 ee 48 89 df 5b 5d e9 ed fc ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa <53> 48 83 ec 10 48 8b 05 10 64 33 00 48 8b 00 48 85 c0 0f 85 84 00 RSP: 002b:00007ffe5d33fab8 EFLAGS: 00000202 RAX: 0000000000000002 RBX: 0000561f72c31460 RCX: 0000561f72c31720 RDX: 0000000000000002 RSI: 0000561f72c31722 RDI: 0000561f72c31720 RBP: 000000000000002a R08: 00007ffe5d33fa40 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 0000561f7187e380 R13: 0000000000000000 R14: 0000000000000000 R15: 0000561f72c31460 </TASK> Modules linked in: sch_ets sch_tbf dummy rfkill iTCO_wdt intel_rapl_msr iTCO_vendor_support intel_rapl_common joydev virtio_balloon lpc_ich i2c_i801 i2c_smbus pcspkr ip_tables xfs libcrc32c crct10dif_pclmul crc32_pclmul crc32c_intel ahci libahci ghash_clmulni_intel serio_raw libata virtio_blk virtio_console virtio_net net_failover failover sunrpc dm_mirror dm_region_hash dm_log dm_mod CR2: 0000000000000018 Ensuring that 'alist' was never zeroed [1] was not sufficient, we need to remove from the active list those elements that are no more SP nor DRR. [1] https://lore.kernel.org/netdev/60d274838bf09777f0371253416e8af71360bc08.1633609148.git.dcaratti@redhat.com/ v3: fix race between ets_qdisc_change() and ets_qdisc_dequeue() delisting DRR classes beyond 'nbands' in ets_qdisc_change() with the qdisc lock acquired, thanks to Cong Wang. v2: when a NULL qdisc is found in the DRR active list, try to dequeue skb from the next list item. Reported-by: Hangbin Liu <liuhangbin@gmail.com> Fixes: dcc68b4d8084 ("net: sch_ets: Add a new Qdisc") Signed-off-by: Davide Caratti <dcaratti@redhat.com> Link: https://lore.kernel.org/r/7a5c496eed2d62241620bdbb83eb03fb9d571c99.1637762721.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-11-24 11:14:40 -05:00
}
q->nstrict = nstrict;
memcpy(q->prio2band, priomap, sizeof(priomap));
for (i = 0; i < q->nbands; i++)
q->classes[i].quantum = quanta[i];
for (i = oldbands; i < q->nbands; i++) {
q->classes[i].qdisc = queues[i];
if (q->classes[i].qdisc != &noop_qdisc)
qdisc_hash_add(q->classes[i].qdisc, true);
}
sch_tree_unlock(sch);
ets_offload_change(sch);
for (i = q->nbands; i < oldbands; i++) {
qdisc_put(q->classes[i].qdisc);
q->classes[i].qdisc = NULL;
q->classes[i].quantum = 0;
q->classes[i].deficit = 0;
gnet_stats_basic_sync_init(&q->classes[i].bstats);
memset(&q->classes[i].qstats, 0, sizeof(q->classes[i].qstats));
}
return 0;
}
static int ets_qdisc_init(struct Qdisc *sch, struct nlattr *opt,
struct netlink_ext_ack *extack)
{
struct ets_sched *q = qdisc_priv(sch);
int err, i;
if (!opt)
return -EINVAL;
err = tcf_block_get(&q->block, &q->filter_list, sch, extack);
if (err)
return err;
INIT_LIST_HEAD(&q->active);
for (i = 0; i < TCQ_ETS_MAX_BANDS; i++)
INIT_LIST_HEAD(&q->classes[i].alist);
return ets_qdisc_change(sch, opt, extack);
}
static void ets_qdisc_reset(struct Qdisc *sch)
{
struct ets_sched *q = qdisc_priv(sch);
int band;
for (band = q->nstrict; band < q->nbands; band++) {
if (q->classes[band].qdisc->q.qlen)
list_del(&q->classes[band].alist);
}
for (band = 0; band < q->nbands; band++)
qdisc_reset(q->classes[band].qdisc);
}
static void ets_qdisc_destroy(struct Qdisc *sch)
{
struct ets_sched *q = qdisc_priv(sch);
int band;
ets_offload_destroy(sch);
tcf_block_put(q->block);
for (band = 0; band < q->nbands; band++)
qdisc_put(q->classes[band].qdisc);
}
static int ets_qdisc_dump(struct Qdisc *sch, struct sk_buff *skb)
{
struct ets_sched *q = qdisc_priv(sch);
struct nlattr *opts;
struct nlattr *nest;
int band;
int prio;
int err;
err = ets_offload_dump(sch);
if (err)
return err;
opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
if (!opts)
goto nla_err;
if (nla_put_u8(skb, TCA_ETS_NBANDS, q->nbands))
goto nla_err;
if (q->nstrict &&
nla_put_u8(skb, TCA_ETS_NSTRICT, q->nstrict))
goto nla_err;
if (q->nbands > q->nstrict) {
nest = nla_nest_start(skb, TCA_ETS_QUANTA);
if (!nest)
goto nla_err;
for (band = q->nstrict; band < q->nbands; band++) {
if (nla_put_u32(skb, TCA_ETS_QUANTA_BAND,
q->classes[band].quantum))
goto nla_err;
}
nla_nest_end(skb, nest);
}
nest = nla_nest_start(skb, TCA_ETS_PRIOMAP);
if (!nest)
goto nla_err;
for (prio = 0; prio <= TC_PRIO_MAX; prio++) {
if (nla_put_u8(skb, TCA_ETS_PRIOMAP_BAND, q->prio2band[prio]))
goto nla_err;
}
nla_nest_end(skb, nest);
return nla_nest_end(skb, opts);
nla_err:
nla_nest_cancel(skb, opts);
return -EMSGSIZE;
}
static const struct Qdisc_class_ops ets_class_ops = {
.change = ets_class_change,
.graft = ets_class_graft,
.leaf = ets_class_leaf,
.find = ets_class_find,
.qlen_notify = ets_class_qlen_notify,
.dump = ets_class_dump,
.dump_stats = ets_class_dump_stats,
.walk = ets_qdisc_walk,
.tcf_block = ets_qdisc_tcf_block,
.bind_tcf = ets_qdisc_bind_tcf,
.unbind_tcf = ets_qdisc_unbind_tcf,
};
static struct Qdisc_ops ets_qdisc_ops __read_mostly = {
.cl_ops = &ets_class_ops,
.id = "ets",
.priv_size = sizeof(struct ets_sched),
.enqueue = ets_qdisc_enqueue,
.dequeue = ets_qdisc_dequeue,
.peek = qdisc_peek_dequeued,
.change = ets_qdisc_change,
.init = ets_qdisc_init,
.reset = ets_qdisc_reset,
.destroy = ets_qdisc_destroy,
.dump = ets_qdisc_dump,
.owner = THIS_MODULE,
};
net/sched: Add module aliases for cls_,sch_,act_ modules No functional change intended, aliases will be used in followup commits. Note for backporters: you may need to add aliases also for modules that are already removed in mainline kernel but still in your version. Patches were generated with the help of Coccinelle scripts like: cat >scripts/coccinelle/misc/tcf_alias.cocci <<EOD virtual patch virtual report @ haskernel @ @@ @ tcf_has_kind depends on report && haskernel @ identifier ops; constant K; @@ static struct tcf_proto_ops ops = { .kind = K, ... }; +char module_alias = K; EOD /usr/bin/spatch -D report --cocci-file scripts/coccinelle/misc/tcf_alias.cocci \ --dir . \ -I ./arch/x86/include -I ./arch/x86/include/generated -I ./include \ -I ./arch/x86/include/uapi -I ./arch/x86/include/generated/uapi \ -I ./include/uapi -I ./include/generated/uapi \ --include ./include/linux/compiler-version.h --include ./include/linux/kconfig.h \ --jobs 8 --chunksize 1 2>/dev/null | \ sed 's/char module_alias = "\([^"]*\)";/MODULE_ALIAS_NET_CLS("\1");/' And analogously for: static struct tc_action_ops ops = { .kind = K, static struct Qdisc_ops ops = { .id = K, (Someone familiar would be able to fit those into one .cocci file without sed post processing.) Signed-off-by: Michal Koutný <mkoutny@suse.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Link: https://lore.kernel.org/r/20240201130943.19536-3-mkoutny@suse.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-02-01 08:09:41 -05:00
MODULE_ALIAS_NET_SCH("ets");
static int __init ets_init(void)
{
return register_qdisc(&ets_qdisc_ops);
}
static void __exit ets_exit(void)
{
unregister_qdisc(&ets_qdisc_ops);
}
module_init(ets_init);
module_exit(ets_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Enhanced Transmission Selection(ETS) scheduler");