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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-06-09 02:09:23 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2010-06-11 18:37:08 -0700 |
| commit | c7de2cf053420d63bac85133469c965d4b1083e1 (patch) | |
| tree | b56f7c96d01e25f79fe1f9b7e5305265e92214d9 /net/sched | |
| parent | cbd6890c5987cd7115147e1dd2c10d729afabb08 (diff) | |
| download | op-kernel-dev-c7de2cf053420d63bac85133469c965d4b1083e1.zip op-kernel-dev-c7de2cf053420d63bac85133469c965d4b1083e1.tar.gz | |
pkt_sched: gen_kill_estimator() rcu fixes
gen_kill_estimator() API is incomplete or not well documented, since
caller should make sure an RCU grace period is respected before
freeing stats_lock.
This was partially addressed in commit 5d944c640b4
(gen_estimator: deadlock fix), but same problem exist for all
gen_kill_estimator() users, if lock they use is not already RCU
protected.
A code review shows xt_RATEEST.c, act_api.c, act_police.c have this
problem. Other are ok because they use qdisc lock, already RCU
protected.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/act_api.c | 11 | ||||
| -rw-r--r-- | net/sched/act_police.c | 12 |
2 files changed, 21 insertions, 2 deletions
diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 972378f..23b25f8 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -26,6 +26,11 @@ #include <net/act_api.h> #include <net/netlink.h> +static void tcf_common_free_rcu(struct rcu_head *head) +{ + kfree(container_of(head, struct tcf_common, tcfc_rcu)); +} + void tcf_hash_destroy(struct tcf_common *p, struct tcf_hashinfo *hinfo) { unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask); @@ -38,7 +43,11 @@ void tcf_hash_destroy(struct tcf_common *p, struct tcf_hashinfo *hinfo) write_unlock_bh(hinfo->lock); gen_kill_estimator(&p->tcfc_bstats, &p->tcfc_rate_est); - kfree(p); + /* + * gen_estimator est_timer() might access p->tcfc_lock + * or bstats, wait a RCU grace period before freeing p + */ + call_rcu(&p->tcfc_rcu, tcf_common_free_rcu); return; } } diff --git a/net/sched/act_police.c b/net/sched/act_police.c index 654f73d..537a487 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -97,6 +97,11 @@ nla_put_failure: goto done; } +static void tcf_police_free_rcu(struct rcu_head *head) +{ + kfree(container_of(head, struct tcf_police, tcf_rcu)); +} + static void tcf_police_destroy(struct tcf_police *p) { unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK); @@ -113,7 +118,11 @@ static void tcf_police_destroy(struct tcf_police *p) qdisc_put_rtab(p->tcfp_R_tab); if (p->tcfp_P_tab) qdisc_put_rtab(p->tcfp_P_tab); - kfree(p); + /* + * gen_estimator est_timer() might access p->tcf_lock + * or bstats, wait a RCU grace period before freeing p + */ + call_rcu(&p->tcf_rcu, tcf_police_free_rcu); return; } } @@ -397,6 +406,7 @@ static void __exit police_cleanup_module(void) { tcf_unregister_action(&act_police_ops); + rcu_barrier(); /* Wait for completion of call_rcu()'s (tcf_police_free_rcu) */ } module_init(police_init_module); |
