BMC/Intel-BMC/linux.git/net/core, branch v4.10.13

make skb_copy_datagram_msg() et.al. preserve ->msg_iter on error

2017-04-21T07:32:40+00:00

commit 3278682123811dd8ef07de5eb701fc4548fcebf2 upstream. Fixes the mess observed in e.g. rsync over a noisy link we'd been seeing since last Summer. What happens is that we copy part of a datagram before noticing a checksum mismatch. Datagram will be resent, all right, but we want the next try go into the same place, not after it... All this family of primitives (copy/checksum and copy a datagram into destination) is "all or nothing" sort of interface - either we get 0 (meaning that copy had been successful) or we get an error (and no way to tell how much had been copied before we ran into whatever error it had been). Make all of them leave iterator unadvanced in case of errors - all callers must be able to cope with that (an error might've been caught before the iterator had been advanced), it costs very little to arrange, it's safer for callers and actually fixes at least one bug in said callers. Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman

cgroup, net_cls: iterate the fds of only the tasks which are being migrated

2017-03-30T07:44:08+00:00

commit a05d4fd9176003e0c1f9c3d083f4dac19fd346ab upstream. The net_cls controller controls the classid field of each socket which is associated with the cgroup. Because the classid is per-socket attribute, when a task migrates to another cgroup or the configured classid of the cgroup changes, the controller needs to walk all sockets and update the classid value, which was implemented by 3b13758f51de ("cgroups: Allow dynamically changing net_classid"). While the approach is not scalable, migrating tasks which have a lot of fds attached to them is rare and the cost is born by the ones initiating the operations. However, for simplicity, both the migration and classid config change paths call update_classid() which scans all fds of all tasks in the target css. This is an overkill for the migration path which only needs to cover a much smaller subset of tasks which are actually getting migrated in. On cgroup v1, this can lead to unexpected scalability issues when one tries to migrate a task or process into a net_cls cgroup which already contains a lot of fds. Even if the migration traget doesn't have many to get scanned, update_classid() ends up scanning all fds in the target cgroup which can be extremely numerous. Unfortunately, on cgroup v2 which doesn't use net_cls, the problem is even worse. Before bfc2cf6f61fc ("cgroup: call subsys->*attach() only for subsystems which are actually affected by migration"), cgroup core would call the ->css_attach callback even for controllers which don't see actual migration to a different css. As net_cls is always disabled but still mounted on cgroup v2, whenever a process is migrated on the cgroup v2 hierarchy, net_cls sees identity migration from root to root and cgroup core used to call ->css_attach callback for those. The net_cls ->css_attach ends up calling update_classid() on the root net_cls css to which all processes on the system belong to as the controller isn't used. This makes any cgroup v2 migration O(total_number_of_fds_on_the_system) which is horrible and easily leads to noticeable stalls triggering RCU stall warnings and so on. The worst symptom is already fixed in upstream by bfc2cf6f61fc ("cgroup: call subsys->*attach() only for subsystems which are actually affected by migration"); however, backporting that commit is too invasive and we want to avoid other cases too. This patch updates net_cls's cgrp_attach() to iterate fds of only the processes which are actually getting migrated. This removes the surprising migration cost which is dependent on the total number of fds in the target cgroup. As this leaves write_classid() the only user of update_classid(), open-code the helper into write_classid(). Reported-by: David Goode Fixes: 3b13758f51de ("cgroups: Allow dynamically changing net_classid") Cc: Nina Schiff Cc: David S. Miller Signed-off-by: Tejun Heo Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: solve a NAPI race

2017-03-30T07:44:02+00:00

commit 39e6c8208d7b6fb9d2047850fb3327db567b564b upstream. While playing with mlx4 hardware timestamping of RX packets, I found that some packets were received by TCP stack with a ~200 ms delay... Since the timestamp was provided by the NIC, and my probe was added in tcp_v4_rcv() while in BH handler, I was confident it was not a sender issue, or a drop in the network. This would happen with a very low probability, but hurting RPC workloads. A NAPI driver normally arms the IRQ after the napi_complete_done(), after NAPI_STATE_SCHED is cleared, so that the hard irq handler can grab it. Problem is that if another point in the stack grabs NAPI_STATE_SCHED bit while IRQ are not disabled, we might have later an IRQ firing and finding this bit set, right before napi_complete_done() clears it. This can happen with busy polling users, or if gro_flush_timeout is used. But some other uses of napi_schedule() in drivers can cause this as well. thread 1 thread 2 (could be on same cpu, or not) // busy polling or napi_watchdog() napi_schedule(); ... napi->poll() device polling: read 2 packets from ring buffer Additional 3rd packet is available. device hard irq // does nothing because NAPI_STATE_SCHED bit is owned by thread 1 napi_schedule(); napi_complete_done(napi, 2); rearm_irq(); Note that rearm_irq() will not force the device to send an additional IRQ for the packet it already signaled (3rd packet in my example) This patch adds a new NAPI_STATE_MISSED bit, that napi_schedule_prep() can set if it could not grab NAPI_STATE_SCHED Then napi_complete_done() properly reschedules the napi to make sure we do not miss something. Since we manipulate multiple bits at once, use cmpxchg() like in sk_busy_loop() to provide proper transactions. In v2, I changed napi_watchdog() to use a relaxed variant of napi_schedule_prep() : No need to set NAPI_STATE_MISSED from this point. In v3, I added more details in the changelog and clears NAPI_STATE_MISSED in busy_poll_stop() In v4, I added the ideas given by Alexander Duyck in v3 review Signed-off-by: Eric Dumazet Cc: Alexander Duyck Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

socket, bpf: fix sk_filter use after free in sk_clone_lock

2017-03-30T07:44:02+00:00

[ Upstream commit a97e50cc4cb67e1e7bff56f6b41cda62ca832336 ] In sk_clone_lock(), we create a new socket and inherit most of the parent's members via sock_copy() which memcpy()'s various sections. Now, in case the parent socket had a BPF socket filter attached, then newsk->sk_filter points to the same instance as the original sk->sk_filter. sk_filter_charge() is then called on the newsk->sk_filter to take a reference and should that fail due to hitting max optmem, we bail out and release the newsk instance. The issue is that commit 278571baca2a ("net: filter: simplify socket charging") wrongly combined the dismantle path with the failure path of xfrm_sk_clone_policy(). This means, even when charging failed, we call sk_free_unlock_clone() on the newsk, which then still points to the same sk_filter as the original sk. Thus, sk_free_unlock_clone() calls into __sk_destruct() eventually where it tests for present sk_filter and calls sk_filter_uncharge() on it, which potentially lets sk_omem_alloc wrap around and releases the eBPF prog and sk_filter structure from the (still intact) parent. Fix it by making sure that when sk_filter_charge() failed, we reset newsk->sk_filter back to NULL before passing to sk_free_unlock_clone(), so that we don't mess with the parents sk_filter. Only if xfrm_sk_clone_policy() fails, we did reach the point where either the parent's filter was NULL and as a result newsk's as well or where we previously had a successful sk_filter_charge(), thus for that case, we do need sk_filter_uncharge() to release the prior taken reference on sk_filter. Fixes: 278571baca2a ("net: filter: simplify socket charging") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: properly release sk_frag.page

2017-03-30T07:44:00+00:00

[ Upstream commit 22a0e18eac7a9e986fec76c60fa4a2926d1291e2 ] I mistakenly added the code to release sk->sk_frag in sk_common_release() instead of sk_destruct() TCP sockets using sk->sk_allocation == GFP_ATOMIC do no call sk_common_release() at close time, thus leaking one (order-3) page. iSCSI is using such sockets. Fixes: 5640f7685831 ("net: use a per task frag allocator") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: use net->count to check whether a netns is alive or not

2017-03-22T11:57:02+00:00

[ Upstream commit 91864f5852f9996210fad400cf70fb85af091243 ] The previous idea was to check whether a net namespace is in net_exit_list or not. It doesn't work, because net->exit_list is used in __register_pernet_operations and __unregister_pernet_operations where all namespaces are added to a temporary list to make cleanup in a error case, so list_empty(&net->exit_list) always returns false. Reported-by: Mantas Mikulėnas Fixes: 002d8a1a6c11 ("net: skip genenerating uevents for network namespaces that are exiting") Signed-off-by: Andrei Vagin Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: fix socket refcounting in skb_complete_tx_timestamp()

2017-03-22T11:56:59+00:00

[ Upstream commit 9ac25fc063751379cb77434fef9f3b088cd3e2f7 ] TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt By the time TX completion happens, sk_refcnt might be already 0. sock_hold()/sock_put() would then corrupt critical state, like sk_wmem_alloc and lead to leaks or use after free. Fixes: 62bccb8cdb69 ("net-timestamp: Make the clone operation stand-alone from phy timestamping") Signed-off-by: Eric Dumazet Cc: Alexander Duyck Cc: Johannes Berg Cc: Soheil Hassas Yeganeh Cc: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: fix socket refcounting in skb_complete_wifi_ack()

2017-03-22T11:56:59+00:00

[ Upstream commit dd4f10722aeb10f4f582948839f066bebe44e5fb ] TX skbs do not necessarily hold a reference on skb->sk->sk_refcnt By the time TX completion happens, sk_refcnt might be already 0. sock_hold()/sock_put() would then corrupt critical state, like sk_wmem_alloc. Fixes: bf7fa551e0ce ("mac80211: Resolve sk_refcnt/sk_wmem_alloc issue in wifi ack path") Signed-off-by: Eric Dumazet Cc: Alexander Duyck Cc: Johannes Berg Cc: Soheil Hassas Yeganeh Cc: Willem de Bruijn Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: net_enable_timestamp() can be called from irq contexts

2017-03-22T11:56:57+00:00

[ Upstream commit 13baa00ad01bb3a9f893e3a08cbc2d072fc0c15d ] It is now very clear that silly TCP listeners might play with enabling/disabling timestamping while new children are added to their accept queue. Meaning net_enable_timestamp() can be called from BH context while current state of the static key is not enabled. Lets play safe and allow all contexts. The work queue is scheduled only under the problematic cases, which are the static key enable/disable transition, to not slow down critical paths. This extends and improves what we did in commit 5fa8bbda38c6 ("net: use a work queue to defer net_disable_timestamp() work") Fixes: b90e5794c5bd ("net: dont call jump_label_dec from irq context") Signed-off-by: Eric Dumazet Reported-by: Dmitry Vyukov Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: neigh: Fix netevent NETEVENT_DELAY_PROBE_TIME_UPDATE notification

2017-02-15T17:38:43+00:00

When setting a neigh related sysctl parameter, we always send a NETEVENT_DELAY_PROBE_TIME_UPDATE netevent. For instance, when executing sysctl net.ipv6.neigh.wlp3s0.retrans_time_ms=2000 a NETEVENT_DELAY_PROBE_TIME_UPDATE netevent is generated. This is caused by commit 2a4501ae18b5 ("neigh: Send a notification when DELAY_PROBE_TIME changes"). According to the commit's description, it was intended to generate such an event when setting the "delay_first_probe_time" sysctl parameter. In order to fix this, only generate this event when actually setting the "delay_first_probe_time" sysctl parameter. This fix should not have any unintended side-effects, because all but one registered netevent callbacks check for other netevent event types (the registered callbacks were obtained by grepping for "register_netevent_notifier"). The only callback that uses the NETEVENT_DELAY_PROBE_TIME_UPDATE event is mlxsw_sp_router_netevent_event() (in drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c): in case of this event, it only accesses the DELAY_PROBE_TIME of the passed neigh_parms. Fixes: 2a4501ae18b5 ("neigh: Send a notification when DELAY_PROBE_TIME changes") Signed-off-by: Marcus Huewe Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller