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5d944c640b
One of my test machine got a deadlock during "tc" sessions, adding/deleting classes & filters, using traffic estimators. After some analysis, I believe we have a potential use after free case in est_timer() : spin_lock(e->stats_lock); << HERE >> read_lock(&est_lock); if (e->bstats == NULL) << TEST >> goto skip; Test is done a bit late, because after estimator is killed, and before rcu grace period elapsed, we might already have freed/reuse memory where e->stats_locks points to (some qdisc->q.lock) A possible fix is to respect a rcu grace period at Qdisc dismantle time. On 64bit, sizeof(struct Qdisc) is exactly 192 bytes. Adding 16 bytes to it (for struct rcu_head) is a problem because it might change performance, given QDISC_ALIGNTO is 32 bytes. This is why I also change QDISC_ALIGNTO to 64 bytes, to satisfy most current alignment requirements. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
116 lines
3.4 KiB
C
116 lines
3.4 KiB
C
#ifndef __NET_PKT_SCHED_H
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#define __NET_PKT_SCHED_H
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#include <linux/jiffies.h>
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#include <linux/ktime.h>
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#include <net/sch_generic.h>
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struct qdisc_walker {
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int stop;
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int skip;
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int count;
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int (*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
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};
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#define QDISC_ALIGNTO 64
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#define QDISC_ALIGN(len) (((len) + QDISC_ALIGNTO-1) & ~(QDISC_ALIGNTO-1))
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static inline void *qdisc_priv(struct Qdisc *q)
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{
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return (char *) q + QDISC_ALIGN(sizeof(struct Qdisc));
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}
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/*
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Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
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Normal IP packet size ~ 512byte, hence:
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0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
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10Mbit ethernet.
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10msec resolution -> <50Kbit/sec.
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The result: [34]86 is not good choice for QoS router :-(
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The things are not so bad, because we may use artifical
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clock evaluated by integration of network data flow
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in the most critical places.
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*/
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typedef u64 psched_time_t;
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typedef long psched_tdiff_t;
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/* Avoid doing 64 bit divide */
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#define PSCHED_SHIFT 6
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#define PSCHED_TICKS2NS(x) ((s64)(x) << PSCHED_SHIFT)
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#define PSCHED_NS2TICKS(x) ((x) >> PSCHED_SHIFT)
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#define PSCHED_TICKS_PER_SEC PSCHED_NS2TICKS(NSEC_PER_SEC)
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#define PSCHED_PASTPERFECT 0
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static inline psched_time_t psched_get_time(void)
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{
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return PSCHED_NS2TICKS(ktime_to_ns(ktime_get()));
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}
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static inline psched_tdiff_t
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psched_tdiff_bounded(psched_time_t tv1, psched_time_t tv2, psched_time_t bound)
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{
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return min(tv1 - tv2, bound);
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}
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struct qdisc_watchdog {
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struct hrtimer timer;
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struct Qdisc *qdisc;
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};
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extern void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);
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extern void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
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psched_time_t expires);
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extern void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);
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extern struct Qdisc_ops pfifo_qdisc_ops;
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extern struct Qdisc_ops bfifo_qdisc_ops;
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extern struct Qdisc_ops pfifo_head_drop_qdisc_ops;
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extern int fifo_set_limit(struct Qdisc *q, unsigned int limit);
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extern struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
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unsigned int limit);
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extern int register_qdisc(struct Qdisc_ops *qops);
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extern int unregister_qdisc(struct Qdisc_ops *qops);
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extern void qdisc_list_del(struct Qdisc *q);
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extern struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
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extern struct Qdisc *qdisc_lookup_class(struct net_device *dev, u32 handle);
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extern struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
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struct nlattr *tab);
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extern void qdisc_put_rtab(struct qdisc_rate_table *tab);
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extern void qdisc_put_stab(struct qdisc_size_table *tab);
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extern void qdisc_warn_nonwc(char *txt, struct Qdisc *qdisc);
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extern int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
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struct net_device *dev, struct netdev_queue *txq,
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spinlock_t *root_lock);
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extern void __qdisc_run(struct Qdisc *q);
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static inline void qdisc_run(struct Qdisc *q)
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{
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if (!test_and_set_bit(__QDISC_STATE_RUNNING, &q->state))
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__qdisc_run(q);
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}
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extern int tc_classify_compat(struct sk_buff *skb, struct tcf_proto *tp,
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struct tcf_result *res);
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extern int tc_classify(struct sk_buff *skb, struct tcf_proto *tp,
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struct tcf_result *res);
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/* Calculate maximal size of packet seen by hard_start_xmit
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routine of this device.
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*/
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static inline unsigned psched_mtu(const struct net_device *dev)
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{
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return dev->mtu + dev->hard_header_len;
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}
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#endif
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