linux-stable.git/net/core/dev.c, branch v5.17.7

net: initialize init_net earlier

2022-04-13T17:27:12+00:00

[ Upstream commit 9c1be1935fb68b2413796cdc03d019b8cf35ab51 ]

While testing a patch that will follow later
("net: add netns refcount tracker to struct nsproxy")
I found that devtmpfs_init() was called before init_net
was initialized.

This is a bug, because devtmpfs_setup() calls
ksys_unshare(CLONE_NEWNS);

This has the effect of increasing init_net refcount,
which will be later overwritten to 1, as part of setup_net(&init_net)

We had too many prior patches [1] trying to work around the root cause.

Really, make sure init_net is in BSS section, and that net_ns_init()
is called earlier at boot time.

Note that another patch ("vfs: add netns refcount tracker
to struct fs_context") also will need net_ns_init() being called
before vfs_caches_init()

As a bonus, this patch saves around 4KB in .data section.

[1]

f8c46cb39079 ("netns: do not call pernet ops for not yet set up init_net namespace")
b5082df8019a ("net: Initialise init_net.count to 1")
734b65417b24 ("net: Statically initialize init_net.dev_base_head")

v2: fixed a build error reported by kernel build bots (CONFIG_NET=n)

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

xdp: check prog type before updating BPF link

2022-01-11T17:44:06+00:00

The bpf_xdp_link_update() function didn't check the program type before
updating the program, which made it possible to install any program type as
an XDP program, which is obviously not good. Syzbot managed to trigger this
by swapping in an LWT program on the XDP hook which would crash in a helper
call.

Fix this by adding a check and bailing out if the types don't match.

Fixes: 026a4c28e1db ("bpf, xdp: Implement LINK_UPDATE for BPF XDP link")
Reported-by: syzbot+983941aa85af6ded1fd9@syzkaller.appspotmail.com
Acked-by: Andrii Nakryiko 
Signed-off-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/r/20220107221115.326171-1-toke@redhat.com
Signed-off-by: Alexei Starovoitov

net: skb: introduce kfree_skb_reason()

2022-01-10T00:30:34+00:00

Introduce the interface kfree_skb_reason(), which is able to pass
the reason why the skb is dropped to 'kfree_skb' tracepoint.

Add the 'reason' field to 'trace_kfree_skb', therefor user can get
more detail information about abnormal skb with 'drop_monitor' or
eBPF.

All drop reasons are defined in the enum 'skb_drop_reason', and
they will be print as string in 'kfree_skb' tracepoint in format
of 'reason: XXX'.

( Maybe the reasons should be defined in a uapi header file, so that
user space can use them? )

Signed-off-by: Menglong Dong 
Signed-off-by: Jakub Kicinski

gro: add ability to control gro max packet size

2022-01-06T12:27:05+00:00

Eric Dumazet suggested to allow users to modify max GRO packet size.

We have seen GRO being disabled by users of appliances (such as
wifi access points) because of claimed bufferbloat issues,
or some work arounds in sch_cake, to split GRO/GSO packets.

Instead of disabling GRO completely, one can chose to limit
the maximum packet size of GRO packets, depending on their
latency constraints.

This patch adds a per device gro_max_size attribute
that can be changed with ip link command.

ip link set dev eth0 gro_max_size 16000

Suggested-by: Eric Dumazet 
Signed-off-by: Coco Li 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2021-12-31T14:35:40+00:00

Alexei Starovoitov says:

====================
pull-request: bpf-next 2021-12-30

The following pull-request contains BPF updates for your *net-next* tree.

We've added 72 non-merge commits during the last 20 day(s) which contain
a total of 223 files changed, 3510 insertions(+), 1591 deletions(-).

The main changes are:

1) Automatic setrlimit in libbpf when bpf is memcg's in the kernel, from Andrii.

2) Beautify and de-verbose verifier logs, from Christy.

3) Composable verifier types, from Hao.

4) bpf_strncmp helper, from Hou.

5) bpf.h header dependency cleanup, from Jakub.

6) get_func_[arg|ret|arg_cnt] helpers, from Jiri.

7) Sleepable local storage, from KP.

8) Extend kfunc with PTR_TO_CTX, PTR_TO_MEM argument support, from Kumar.
====================

Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-12-24T00:09:58+00:00

include/net/sock.h
  commit 8f905c0e7354 ("inet: fully convert sk->sk_rx_dst to RCU rules")
  commit 43f51df41729 ("net: move early demux fields close to sk_refcnt")
  https://lore.kernel.org/all/20211222141641.0caa0ab3@canb.auug.org.au/

Signed-off-by: Jakub Kicinski

net/sched: Extend qdisc control block with tc control block

2021-12-18T02:06:35+00:00

BPF layer extends the qdisc control block via struct bpf_skb_data_end
and because of that there is no more room to add variables to the
qdisc layer control block without going over the skb->cb size.

Extend the qdisc control block with a tc control block,
and move all tc related variables to there as a pre-step for
extending the tc control block with additional members.

Signed-off-by: Paul Blakey 
Signed-off-by: Jakub Kicinski

net: dev: Change the order of the arguments for the contended condition.

2021-12-14T12:34:08+00:00

Change the order of arguments and make qdisc_is_running() appear first.
This is more readable for the general case.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: David S. Miller

bpf: Let bpf_warn_invalid_xdp_action() report more info

2021-12-13T21:28:27+00:00

In non trivial scenarios, the action id alone is not sufficient to
identify the program causing the warning. Before the previous patch,
the generated stack-trace pointed out at least the involved device
driver.

Let's additionally include the program name and id, and the relevant
device name.

If the user needs additional infos, he can fetch them via a kernel
probe, leveraging the arguments added here.

Signed-off-by: Paolo Abeni 
Signed-off-by: Daniel Borkmann 
Acked-by: Toke Høiland-Jørgensen 
Link: https://lore.kernel.org/bpf/ddb96bb975cbfddb1546cf5da60e77d5100b533c.1638189075.git.pabeni@redhat.com

net: dev: Always serialize on Qdisc::busylock in __dev_xmit_skb() on PREEMPT_RT.

2021-12-13T14:57:03+00:00

The root-lock is dropped before dev_hard_start_xmit() is invoked and after
setting the __QDISC___STATE_RUNNING bit. If the Qdisc owner is preempted
by another sender/task with a higher priority then this new sender won't
be able to submit packets to the NIC directly instead they will be
enqueued into the Qdisc. The NIC will remain idle until the Qdisc owner
is scheduled again and finishes the job.

By serializing every task on the ->busylock then the task will be
preempted by a sender only after the Qdisc has no owner.

Always serialize on the busylock on PREEMPT_RT.

Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: David S. Miller