kernel.git/net/sched/act_api.c, branch linux-4.10.y

net sched actions: decrement module reference count after table flush.

2017-03-22T11:56:56Z

[ Upstream commit edb9d1bff4bbe19b8ae0e71b1f38732591a9eeb2 ] When tc actions are loaded as a module and no actions have been installed, flushing them would result in actions removed from the memory, but modules reference count not being decremented, so that the modules would not be unloaded. Following is example with GACT action: % sudo modprobe act_gact % lsmod Module Size Used by act_gact 16384 0 % % sudo tc actions ls action gact % % sudo tc actions flush action gact % lsmod Module Size Used by act_gact 16384 1 % sudo tc actions flush action gact % lsmod Module Size Used by act_gact 16384 2 % sudo rmmod act_gact rmmod: ERROR: Module act_gact is in use .... After the fix: % lsmod Module Size Used by act_gact 16384 0 % % sudo tc actions add action pass index 1 % sudo tc actions add action pass index 2 % sudo tc actions add action pass index 3 % lsmod Module Size Used by act_gact 16384 3 % % sudo tc actions flush action gact % lsmod Module Size Used by act_gact 16384 0 % % sudo tc actions flush action gact % lsmod Module Size Used by act_gact 16384 0 % sudo rmmod act_gact % lsmod Module Size Used by % Fixes: f97017cdefef ("net-sched: Fix actions flushing") Signed-off-by: Roman Mashak Signed-off-by: Jamal Hadi Salim Acked-by: Cong Wang Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net sched actions: fix refcnt when GETing of action after bind

2017-01-17T00:43:19Z

Demonstrating the issue: .. add a drop action $sudo $TC actions add action drop index 10 .. retrieve it $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 0 installed 29 sec used 29 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... bug 1 above: reference is two. Reference is actually 1 but we forget to subtract 1. ... do a GET again and we see the same issue try a few times and nothing changes ~$ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 0 installed 31 sec used 31 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 ... lets try to bind the action to a filter.. $ sudo $TC qdisc add dev lo ingress $ sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \ u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 10 ... and now a few GETs: $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 3 bind 1 installed 204 sec used 204 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 4 bind 1 installed 206 sec used 206 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 5 bind 1 installed 235 sec used 235 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 .... as can be observed the reference count keeps going up. After the fix $ sudo $TC actions add action drop index 10 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 1 bind 0 installed 4 sec used 4 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 1 bind 0 installed 6 sec used 6 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC qdisc add dev lo ingress $ sudo $TC filter add dev lo parent ffff: protocol ip prio 1 \ u32 match ip dst 127.0.0.1/32 flowid 1:1 action gact index 10 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 1 installed 32 sec used 32 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 $ sudo $TC -s actions get action gact index 10 action order 1: gact action drop random type none pass val 0 index 10 ref 2 bind 1 installed 33 sec used 33 sec Action statistics: Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0) backlog 0b 0p requeues 0 Fixes: aecc5cefc389 ("net sched actions: fix GETing actions") Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net_sched: gen_estimator: complete rewrite of rate estimators

2016-12-05T20:21:59Z

1) Old code was hard to maintain, due to complex lock chains. (We probably will be able to remove some kfree_rcu() in callers) 2) Using a single timer to update all estimators does not scale. 3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity is not supposed to work well) In this rewrite : - I removed the RB tree that had to be scanned in gen_estimator_active(). qdisc dumps should be much faster. - Each estimator has its own timer. - Estimations are maintained in net_rate_estimator structure, instead of dirtying the qdisc. Minor, but part of the simplification. - Reading the estimator uses RCU and a seqcount to provide proper support for 32bit kernels. - We reduce memory need when estimators are not used, since we store a pointer, instead of the bytes/packets counters. - xt_rateest_mt() no longer has to grab a spinlock. (In the future, xt_rateest_tg() could be switched to per cpu counters) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

net_sched actions: use nla_parse_nested()

2016-10-29T19:01:01Z

Use nla_parse_nested instead of open-coding the call to nla_parse() with the attribute data/len. Signed-off-by: Johannes Berg Acked-by: Cong Wang Signed-off-by: David S. Miller

net_sched: reorder pernet ops and act ops registrations

2016-10-13T14:26:43Z

Krister reported a kernel NULL pointer dereference after tcf_action_init_1() invokes a_o->init(), it is a race condition where one thread calling tcf_register_action() to initialize the netns data after putting act ops in the global list and the other thread searching the list and then calling a_o->init(net, ...). Fix this by moving the pernet ops registration before making the action ops visible. This is fine because: a) we don't rely on act_base in pernet ops->init(), b) in the worst case we have a fully initialized netns but ops is still not ready so new actions still can't be created. Reported-by: Krister Johansen Tested-by: Krister Johansen Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net sched actions: fix GETing actions

2016-09-21T03:34:55Z

With the batch changes that translated transient actions into a temporary list lost in the translation was the fact that tcf_action_destroy() will eventually delete the action from the permanent location if the refcount is zero. Example of what broke: ...add a gact action to drop sudo $TC actions add action drop index 10 ...now retrieve it, looks good sudo $TC actions get action gact index 10 ...retrieve it again and find it is gone! sudo $TC actions get action gact index 10 Fixes: 22dc13c837c3 ("net_sched: convert tcf_exts from list to pointer array"), Fixes: 824a7e8863b3 ("net_sched: remove an unnecessary list_del()") Fixes: f07fed82ad79 ("net_sched: remove the leftover cleanup_a()") Acked-by: Cong Wang Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net sched: stylistic cleanups

2016-09-20T02:04:14Z

Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net_sched: convert tcf_exts from list to pointer array

2016-08-17T23:27:51Z

As pointed out by Jamal, an action could be shared by multiple filters, so we can't use list to chain them any more after we get rid of the original tc_action. Instead, we could just save pointers to these actions in tcf_exts, since they are refcount'ed, so convert the list to an array of pointers. The "ugly" part is the action API still accepts list as a parameter, I just introduce a helper function to convert the array of pointers to a list, instead of relying on the C99 feature to iterate the array. Fixes: a85a970af265 ("net_sched: move tc_action into tcf_common") Reported-by: Jamal Hadi Salim Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net_sched: remove an unnecessary list_del()

2016-08-17T23:27:51Z

This list_del() for tc action is not needed actually, because we only use this list to chain bulk operations, therefore should not be carried for latter operations. Fixes: ec0595cc4495 ("net_sched: get rid of struct tcf_common") Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller

net_sched: remove the leftover cleanup_a()

2016-08-17T23:27:51Z

After refactoring tc_action into tcf_common, we no longer need to cleanup temporary "actions" in list, they are permanently stored in the hashtable. Fixes: a85a970af265 ("net_sched: move tc_action into tcf_common") Reported-by: Jamal Hadi Salim Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller