Commit Graph

68108 Commits

Author SHA1 Message Date
Eric Dumazet
ede6c39c4f net: make net->dev_unreg_count atomic
Having to acquire rtnl from netdev_run_todo() for every dismantled
device is not desirable when/if rtnl is under stress.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10 15:30:26 +00:00
Jakub Kicinski
3ebb0b1032 net: ping6: support setting socket options via cmsg
Minor reordering of the code and a call to sock_cmsg_send()
gives us support for setting the common socket options via
cmsg (the usual ones - SO_MARK, SO_TIMESTAMPING_OLD, SCM_TXTIME).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10 15:04:51 +00:00
Jakub Kicinski
e7b060460f net: ping6: support packet timestamping
Nothing prevents the user from requesting timestamping
on ping6 sockets, yet timestamps are not going to be reported.
Plumb the flags through.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10 15:04:51 +00:00
Jakub Kicinski
4265223946 net: ping6: remove a pr_debug() statement
We have ftrace and BPF today, there's no need for printing arguments
at the start of a function.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10 15:04:51 +00:00
David S. Miller
9557167bc6 Merge tag 'ieee802154-for-davem-2022-02-10' of git://git.kernel.org/pub/scm/linux/kernel/git/sschmidt/wpan-next
Stefan Schmidt says:

====================
pull-request: ieee802154-next 2022-02-10

An update from ieee802154 for your *net-next* tree.

There is more ongoing in ieee802154 than usual. This will be the first pull
request for this cycle, but I expect one more. Depending on review and rework
times.

Pavel Skripkin ported the atusb driver over to the new USB api to avoid unint
problems as well as making use of the modern api without kmalloc() needs in he
driver.

Miquel Raynal landed some changes to ensure proper frame checksum checking with
hwsim, documenting our use of wake and stop_queue and eliding a magic value by
using the proper define.

David Girault documented the address struct used in ieee802154.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-10 14:28:04 +00:00
Jakub Kicinski
4523082982 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next
Pablo Neira Ayuso says:

====================
Netfilter updates for net-next

1) Conntrack sets on CHECKSUM_UNNECESSARY for UDP packet with no checksum,
   from Kevin Mitchell.

2) skb->priority support for nfqueue, from Nicolas Dichtel.

3) Remove conntrack extension register API, from Florian Westphal.

4) Move nat destroy hook to nf_nat_hook instead, to remove
   nf_ct_ext_destroy(), also from Florian.

5) Wrap pptp conntrack NAT hooks into single structure, from Florian Westphal.

6) Support for tcp option set to noop for nf_tables, also from Florian.

7) Do not run x_tables comment match from packet path in nf_tables,
   from Florian Westphal.

8) Replace spinlock by cmpxchg() loop to update missed ct event,
   from Florian Westphal.

9) Wrap cttimeout hooks into single structure, from Florian.

10) Add fast nft_cmp expression for up to 16-bytes.

11) Use cb->ctx to store context in ctnetlink dump, instead of using
    cb->args[], from Florian Westphal.

* git://git.kernel.org/pub/scm/linux/kernel/git/netfilter/nf-next:
  netfilter: ctnetlink: use dump structure instead of raw args
  nfqueue: enable to set skb->priority
  netfilter: nft_cmp: optimize comparison for 16-bytes
  netfilter: cttimeout: use option structure
  netfilter: ecache: don't use nf_conn spinlock
  netfilter: nft_compat: suppress comment match
  netfilter: exthdr: add support for tcp option removal
  netfilter: conntrack: pptp: use single option structure
  netfilter: conntrack: remove extension register api
  netfilter: conntrack: handle ->destroy hook via nat_ops instead
  netfilter: conntrack: move extension sizes into core
  netfilter: conntrack: make all extensions 8-byte alignned
  netfilter: nfqueue: enable to get skb->priority
  netfilter: conntrack: mark UDP zero checksum as CHECKSUM_UNNECESSARY
====================

Link: https://lore.kernel.org/r/20220209133616.165104-1-pablo@netfilter.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09 21:35:08 -08:00
Sebastian Andrzej Siewior
4f9bf2a2f5 tcp: Don't acquire inet_listen_hashbucket::lock with disabled BH.
Commit
   9652dc2eb9 ("tcp: relax listening_hash operations")

removed the need to disable bottom half while acquiring
listening_hash.lock. There are still two callers left which disable
bottom half before the lock is acquired.

On PREEMPT_RT the softirqs are preemptible and local_bh_disable() acts
as a lock to ensure that resources, that are protected by disabling
bottom halves, remain protected.
This leads to a circular locking dependency if the lock acquired with
disabled bottom halves is also acquired with enabled bottom halves
followed by disabling bottom halves. This is the reverse locking order.
It has been observed with inet_listen_hashbucket:🔒

local_bh_disable() + spin_lock(&ilb->lock):
  inet_listen()
    inet_csk_listen_start()
      sk->sk_prot->hash() := inet_hash()
	local_bh_disable()
	__inet_hash()
	  spin_lock(&ilb->lock);
	    acquire(&ilb->lock);

Reverse order: spin_lock(&ilb2->lock) + local_bh_disable():
  tcp_seq_next()
    listening_get_next()
      spin_lock(&ilb2->lock);
	acquire(&ilb2->lock);

  tcp4_seq_show()
    get_tcp4_sock()
      sock_i_ino()
	read_lock_bh(&sk->sk_callback_lock);
	  acquire(softirq_ctrl)	// <---- whoops
	  acquire(&sk->sk_callback_lock)

Drop local_bh_disable() around __inet_hash() which acquires
listening_hash->lock. Split inet_unhash() and acquire the
listen_hashbucket lock without disabling bottom halves; the inet_ehash
lock with disabled bottom halves.

Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lkml.kernel.org/r/12d6f9879a97cd56c09fb53dee343cbb14f7f1f7.camel@gmx.de
Link: https://lkml.kernel.org/r/X9CheYjuXWc75Spa@hirez.programming.kicks-ass.net
Link: https://lore.kernel.org/r/YgQOebeZ10eNx1W6@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09 21:28:36 -08:00
Jakub Kicinski
1127170d45 Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Daniel Borkmann says:

====================
pull-request: bpf-next 2022-02-09

We've added 126 non-merge commits during the last 16 day(s) which contain
a total of 201 files changed, 4049 insertions(+), 2215 deletions(-).

The main changes are:

1) Add custom BPF allocator for JITs that pack multiple programs into a huge
   page to reduce iTLB pressure, from Song Liu.

2) Add __user tagging support in vmlinux BTF and utilize it from BPF
   verifier when generating loads, from Yonghong Song.

3) Add per-socket fast path check guarding from cgroup/BPF overhead when
   used by only some sockets, from Pavel Begunkov.

4) Continued libbpf deprecation work of APIs/features and removal of their
   usage from samples, selftests, libbpf & bpftool, from Andrii Nakryiko
   and various others.

5) Improve BPF instruction set documentation by adding byte swap
   instructions and cleaning up load/store section, from Christoph Hellwig.

6) Switch BPF preload infra to light skeleton and remove libbpf dependency
   from it, from Alexei Starovoitov.

7) Fix architecture-agnostic macros in libbpf for accessing syscall
   arguments from BPF progs for non-x86 architectures,
   from Ilya Leoshkevich.

8) Rework port members in struct bpf_sk_lookup and struct bpf_sock to be
   of 16-bit field with anonymous zero padding, from Jakub Sitnicki.

9) Add new bpf_copy_from_user_task() helper to read memory from a different
   task than current. Add ability to create sleepable BPF iterator progs,
   from Kenny Yu.

10) Implement XSK batching for ice's zero-copy driver used by AF_XDP and
    utilize TX batching API from XSK buffer pool, from Maciej Fijalkowski.

11) Generate temporary netns names for BPF selftests to avoid naming
    collisions, from Hangbin Liu.

12) Implement bpf_core_types_are_compat() with limited recursion for
    in-kernel usage, from Matteo Croce.

13) Simplify pahole version detection and finally enable CONFIG_DEBUG_INFO_DWARF5
    to be selected with CONFIG_DEBUG_INFO_BTF, from Nathan Chancellor.

14) Misc minor fixes to libbpf and selftests from various folks.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (126 commits)
  selftests/bpf: Cover 4-byte load from remote_port in bpf_sk_lookup
  bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide
  libbpf: Fix compilation warning due to mismatched printf format
  selftests/bpf: Test BPF_KPROBE_SYSCALL macro
  libbpf: Add BPF_KPROBE_SYSCALL macro
  libbpf: Fix accessing the first syscall argument on s390
  libbpf: Fix accessing the first syscall argument on arm64
  libbpf: Allow overriding PT_REGS_PARM1{_CORE}_SYSCALL
  selftests/bpf: Skip test_bpf_syscall_macro's syscall_arg1 on arm64 and s390
  libbpf: Fix accessing syscall arguments on riscv
  libbpf: Fix riscv register names
  libbpf: Fix accessing syscall arguments on powerpc
  selftests/bpf: Use PT_REGS_SYSCALL_REGS in bpf_syscall_macro
  libbpf: Add PT_REGS_SYSCALL_REGS macro
  selftests/bpf: Fix an endianness issue in bpf_syscall_macro test
  bpf: Fix bpf_prog_pack build HPAGE_PMD_SIZE
  bpf: Fix leftover header->pages in sparc and powerpc code.
  libbpf: Fix signedness bug in btf_dump_array_data()
  selftests/bpf: Do not export subtest as standalone test
  bpf, x86_64: Fail gracefully on bpf_jit_binary_pack_finalize failures
  ...
====================

Link: https://lore.kernel.org/r/20220209210050.8425-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09 18:40:56 -08:00
Menglong Dong
5cad527d5f net: drop_monitor: support drop reason
In the commit c504e5c2f9 ("net: skb: introduce kfree_skb_reason()")
drop reason is introduced to the tracepoint of kfree_skb. Therefore,
drop_monitor is able to report the drop reason to users by netlink.

The drop reasons are reported as string to users, which is exactly
the same as what we do when reporting it to ftrace.

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220209060838.55513-1-imagedong@tencent.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-09 17:25:57 -08:00
Jakub Sitnicki
9a69e2b385 bpf: Make remote_port field in struct bpf_sk_lookup 16-bit wide
remote_port is another case of a BPF context field documented as a 32-bit
value in network byte order for which the BPF context access converter
generates a load of a zero-padded 16-bit integer in network byte order.

First such case was dst_port in bpf_sock which got addressed in commit
4421a58271 ("bpf: Make dst_port field in struct bpf_sock 16-bit wide").

Loading 4-bytes from the remote_port offset and converting the value with
bpf_ntohl() leads to surprising results, as the expected value is shifted
by 16 bits.

Reduce the confusion by splitting the field in two - a 16-bit field holding
a big-endian integer, and a 16-bit zero-padding anonymous field that
follows it.

Suggested-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220209184333.654927-2-jakub@cloudflare.com
2022-02-09 11:40:45 -08:00
Matt Johnston
63ed1aab3d mctp: Add SIOCMCTP{ALLOC,DROP}TAG ioctls for tag control
This change adds a couple of new ioctls for mctp sockets:
SIOCMCTPALLOCTAG and SIOCMCTPDROPTAG.  These ioctls provide facilities
for explicit allocation / release of tags, overriding the automatic
allocate-on-send/release-on-reply and timeout behaviours. This allows
userspace more control over messages that may not fit a simple
request/response model.

In order to indicate a pre-allocated tag to the sendmsg() syscall, we
introduce a new flag to the struct sockaddr_mctp.smctp_tag value:
MCTP_TAG_PREALLOC.

Additional changes from Jeremy Kerr <jk@codeconstruct.com.au>.

Contains a fix that was:
Reported-by: kernel test robot <lkp@intel.com>

Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 12:00:11 +00:00
Jeremy Kerr
0de55a7d11 mctp: Allow keys matching any local address
Currently, we require an exact match on an incoming packet's dest
address, and the key's local_addr field.

In a future change, we may want to set up a key before packets are
routed, meaning we have no local address to match on.

This change allows key lookups to match on local_addr = MCTP_ADDR_ANY.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 12:00:11 +00:00
Jeremy Kerr
8069b22d65 mctp: Add helper for address match checking
Currently, we have a couple of paths that check that an EID matches, or
the match value is MCTP_ADDR_ANY.

Rather than open coding this, add a little helper.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 12:00:11 +00:00
Jeremy Kerr
c575521462 mctp: tests: Add key state tests
This change adds a few more tests to check the key/tag lookups on route
input. We add a specific entry to the keys lists, route a packet with
specific header values, and check for key match/mismatch.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 12:00:11 +00:00
Jeremy Kerr
62a2b005c6 mctp: tests: Rename FL_T macro to FL_TO
This is a definition for the tag-owner flag, which has TO as a standard
abbreviation. We'll want to add a helper for the actual tag value in a
future change.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 12:00:11 +00:00
Eric Dumazet
3a5f238f2b ip6_tunnel: fix possible NULL deref in ip6_tnl_xmit
Make sure to test that skb has a dst attached to it.

general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 0 PID: 32650 Comm: syz-executor.4 Not tainted 5.17.0-rc2-next-20220204-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:ip6_tnl_xmit+0x2140/0x35f0 net/ipv6/ip6_tunnel.c:1127
Code: 4d 85 f6 0f 85 c5 04 00 00 e8 9c b0 66 f9 48 83 e3 fe 48 b8 00 00 00 00 00 fc ff df 48 8d bb 88 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 07 7f 05 e8 11 25 b2 f9 44 0f b6 b3 88 00 00
RSP: 0018:ffffc900141b7310 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000c77a000
RDX: 0000000000000011 RSI: ffffffff8811f854 RDI: 0000000000000088
RBP: ffffc900141b7480 R08: 0000000000000000 R09: 0000000000000008
R10: ffffffff8811f846 R11: 0000000000000008 R12: ffffc900141b7548
R13: ffff8880297c6000 R14: 0000000000000000 R15: ffff8880351c8dc0
FS:  00007f9827ba2700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b31322000 CR3: 0000000033a70000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ipxip6_tnl_xmit net/ipv6/ip6_tunnel.c:1386 [inline]
 ip6_tnl_start_xmit+0x71e/0x1830 net/ipv6/ip6_tunnel.c:1435
 __netdev_start_xmit include/linux/netdevice.h:4683 [inline]
 netdev_start_xmit include/linux/netdevice.h:4697 [inline]
 xmit_one net/core/dev.c:3473 [inline]
 dev_hard_start_xmit+0x1eb/0x920 net/core/dev.c:3489
 __dev_queue_xmit+0x2a24/0x3760 net/core/dev.c:4116
 packet_snd net/packet/af_packet.c:3057 [inline]
 packet_sendmsg+0x2265/0x5460 net/packet/af_packet.c:3084
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:725
 sock_write_iter+0x289/0x3c0 net/socket.c:1061
 call_write_iter include/linux/fs.h:2075 [inline]
 do_iter_readv_writev+0x47a/0x750 fs/read_write.c:726
 do_iter_write+0x188/0x710 fs/read_write.c:852
 vfs_writev+0x1aa/0x630 fs/read_write.c:925
 do_writev+0x27f/0x300 fs/read_write.c:968
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f9828c2d059

Fixes: c1f55c5e04 ("ip6_tunnel: allow routing IPv4 traffic in NBMA mode")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Qing Deng <i@moy.cat>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-09 11:56:19 +00:00
Florian Westphal
5948ed297e netfilter: ctnetlink: use dump structure instead of raw args
netlink_dump structure has a union of 'long args[6]' and a context
buffer as scratch space.

Convert ctnetlink to use a structure, its easier to read than the
raw 'args' usage which comes with no type checks and no readable names.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-02-09 12:07:16 +01:00
Nicolas Dichtel
98eee88b8d nfqueue: enable to set skb->priority
This is a follow up of the previous patch that enables to get
skb->priority. It's now posssible to set it also.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Florian Westphal <fw@strlen.de>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-02-09 12:04:03 +01:00
Pablo Neira Ayuso
23f68d4629 netfilter: nft_cmp: optimize comparison for 16-bytes
Allow up to 16-byte comparisons with a new cmp fast version. Use two
64-bit words and calculate the mask representing the bits to be
compared. Make sure the comparison is 64-bit aligned and avoid
out-of-bound memory access on registers.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-02-09 12:00:28 +01:00
Florian Westphal
7afa38831a netfilter: cttimeout: use option structure
Instead of two exported functions, export a single option structure.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-02-09 11:56:06 +01:00
Florian Westphal
8dd8678e42 netfilter: ecache: don't use nf_conn spinlock
For updating eache missed value we can use cmpxchg.
This also avoids need to disable BH.

kernel robot reported build failure on v1 because not all arches support
cmpxchg for u16, so extend this to u32.

This doesn't increase struct size, existing padding is used.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-02-09 11:44:03 +01:00
Eric Dumazet
ee403248fa net: remove default_device_exit()
For some reason default_device_ops kept two exit method:

1) default_device_exit() is called for each netns being dismantled in
a cleanup_net() round. This acquires rtnl for each invocation.

2) default_device_exit_batch() is called once with the list of all netns
int the batch, allowing for a single rtnl invocation.

Get rid of the .exit() method to handle the logic from
default_device_exit_batch(), to decrease the number of rtnl acquisition
to one.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:35 -08:00
Eric Dumazet
ef0de6696c can: gw: switch cangw_pernet_exit() to batch mode
cleanup_net() is competing with other rtnl users.

Avoiding to acquire rtnl for each netns before calling
cgw_remove_all_jobs() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:35 -08:00
Eric Dumazet
696e595f70 ipmr: introduce ipmr_net_exit_batch()
cleanup_net() is competing with other rtnl users.

Avoiding to acquire rtnl for each netns before calling
ipmr_rules_exit() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:34 -08:00
Eric Dumazet
e2f736b753 ip6mr: introduce ip6mr_net_exit_batch()
cleanup_net() is competing with other rtnl users.

Avoiding to acquire rtnl for each netns before calling
ip6mr_rules_exit() gives chance for cleanup_net()
to progress much faster, holding rtnl a bit longer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:34 -08:00
Eric Dumazet
ea3e91666d ipv6: change fib6_rules_net_exit() to batch mode
cleanup_net() is competing with other rtnl users.

fib6_rules_net_exit() seems a good candidate for exit_batch(),
as this gives chance for cleanup_net() to progress much faster,
holding rtnl a bit longer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:34 -08:00
Eric Dumazet
1c69576461 ipv4: add fib_net_exit_batch()
cleanup_net() is competing with other rtnl users.

Instead of acquiring rtnl at each fib_net_exit() invocation,
add fib_net_exit_batch() so that rtnl is acquired once.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:33 -08:00
Eric Dumazet
fea7b20132 nexthop: change nexthop_net_exit() to nexthop_net_exit_batch()
cleanup_net() is competing with other rtnl users.

nexthop_net_exit() seems a good candidate for exit_batch(),
as this gives chance for cleanup_net() to progress much faster,
holding rtnl a bit longer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:33 -08:00
Eric Dumazet
e66d117222 ipv6/addrconf: switch to per netns inet6_addr_lst hash table
IPv6 does not scale very well with the number of IPv6 addresses.
It uses a global (shared by all netns) hash table with 256 buckets.

Some functions like addrconf_verify_rtnl() and addrconf_ifdown()
have to iterate all addresses in the hash table.

I have seen addrconf_verify_rtnl() holding the cpu for 10ms or more.

Switch to the per netns hashtable (and spinlock) added
in prior patches.

This considerably speeds up netns dismantle times on hosts
with thousands of netns. This also has an impact
on regular (fast path) IPv6 processing.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:32 -08:00
Eric Dumazet
8805d13ff1 ipv6/addrconf: use one delayed work per netns
Next step for using per netns inet6_addr_lst
is to have per netns work item to ultimately
call addrconf_verify_rtnl() and addrconf_verify()
with a new 'struct net*' argument.

Everything is still using the global inet6_addr_lst[] table.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:32 -08:00
Eric Dumazet
21a216a8fc ipv6/addrconf: allocate a per netns hash table
Add a per netns hash table and a dedicated spinlock,
first step to get rid of the global inet6_addr_lst[] one.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:41:32 -08:00
Eric Dumazet
b2309a71c1 net: add dev->dev_registered_tracker
Convert one dev_hold()/dev_put() pair in register_netdevice()
and unregister_netdevice_many() to dev_hold_track()
and dev_put_track().

This would allow to detect a rogue dev_put() a bit earlier.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20220207184107.1401096-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-08 20:23:20 -08:00
Guillaume Nault
32ccf11079 ipv4: Use dscp_t in struct fib_alias
Use the new dscp_t type to replace the fa_tos field of fib_alias. This
ensures ECN bits are ignored and makes the field compatible with the
fc_dscp field of struct fib_config.

Converting old *tos variables and fields to dscp_t allows sparse to
flag incorrect uses of DSCP and ECN bits. This patch is entirely about
type annotation and shouldn't change any existing behaviour.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-07 20:12:46 -08:00
Guillaume Nault
f55fbb6afb ipv4: Reject routes specifying ECN bits in rtm_tos
Use the new dscp_t type to replace the fc_tos field of fib_config, to
ensure IPv4 routes aren't influenced by ECN bits when configured with
non-zero rtm_tos.

Before this patch, IPv4 routes specifying an rtm_tos with some of the
ECN bits set were accepted. However they wouldn't work (never match) as
IPv4 normally clears the ECN bits with IPTOS_RT_MASK before doing a FIB
lookup (although a few buggy code paths don't).

After this patch, IPv4 routes specifying an rtm_tos with any ECN bit
set is rejected.

Note: IPv6 routes ignore rtm_tos altogether, any rtm_tos is accepted,
but treated as if it were 0.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-07 20:12:46 -08:00
Guillaume Nault
563f8e97e0 ipv4: Stop taking ECN bits into account in fib4-rules
Use the new dscp_t type to replace the tos field of struct fib4_rule,
so that fib4-rules consistently ignore ECN bits.

Before this patch, fib4-rules did accept rules with the high order ECN
bit set (but not the low order one). Also, it relied on its callers
masking the ECN bits of ->flowi4_tos to prevent those from influencing
the result. This was brittle and a few call paths still do the lookup
without masking the ECN bits first.

After this patch fib4-rules only compare the DSCP bits. ECN can't
influence the result anymore, even if the caller didn't mask these
bits. Also, fib4-rules now must have both ECN bits cleared or they will
be rejected.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-07 20:12:46 -08:00
Guillaume Nault
a410a0cf98 ipv6: Define dscp_t and stop taking ECN bits into account in fib6-rules
Define a dscp_t type and its appropriate helpers that ensure ECN bits
are not taken into account when handling DSCP.

Use this new type to replace the tclass field of struct fib6_rule, so
that fib6-rules don't get influenced by ECN bits anymore.

Before this patch, fib6-rules didn't make any distinction between the
DSCP and ECN bits. Therefore, rules specifying a DSCP (tos or dsfield
options in iproute2) stopped working as soon a packets had at least one
of its ECN bits set (as a work around one could create four rules for
each DSCP value to match, one for each possible ECN value).

After this patch fib6-rules only compare the DSCP bits. ECN doesn't
influence the result anymore. Also, fib6-rules now must have the ECN
bits cleared or they will be rejected.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-02-07 20:12:45 -08:00
Stanislav Fomichev
5d1e9f437d bpf: test_run: Fix overflow in bpf_test_finish frags parsing
This place also uses signed min_t and passes this singed int to
copy_to_user (which accepts unsigned argument). I don't think
there is an issue, but let's be consistent.

Fixes: 7855e0db15 ("bpf: test_run: add xdp_shared_info pointer in bpf_test_finish signature")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220204235849.14658-2-sdf@google.com
2022-02-07 18:26:13 -08:00
Stanislav Fomichev
9d63b59d1e bpf: test_run: Fix overflow in xdp frags parsing
When kattr->test.data_size_in > INT_MAX, signed min_t will assign
negative value to data_len. This negative value then gets passed
over to copy_from_user where it is converted to (big) unsigned.

Use unsigned min_t to avoid this overflow.

usercopy: Kernel memory overwrite attempt detected to wrapped address
(offset 0, size 18446612140539162846)!
------------[ cut here ]------------
kernel BUG at mm/usercopy.c:102!
invalid opcode: 0000 [#1] SMP KASAN
Modules linked in:
CPU: 0 PID: 3781 Comm: syz-executor226 Not tainted 4.15.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
RIP: 0010:usercopy_abort+0xbd/0xbf mm/usercopy.c:102
RSP: 0018:ffff8801e9703a38 EFLAGS: 00010286
RAX: 000000000000006c RBX: ffffffff84fc7040 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff816560a2 RDI: ffffed003d2e0739
RBP: ffff8801e9703a90 R08: 000000000000006c R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff84fc73a0
R13: ffffffff84fc7180 R14: ffffffff84fc7040 R15: ffffffff84fc7040
FS:  00007f54e0bec300(0000) GS:ffff8801f6600000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000280 CR3: 00000001e90ea000 CR4: 00000000003426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 check_bogus_address mm/usercopy.c:155 [inline]
 __check_object_size mm/usercopy.c:263 [inline]
 __check_object_size.cold+0x8c/0xad mm/usercopy.c:253
 check_object_size include/linux/thread_info.h:112 [inline]
 check_copy_size include/linux/thread_info.h:143 [inline]
 copy_from_user include/linux/uaccess.h:142 [inline]
 bpf_prog_test_run_xdp+0xe57/0x1240 net/bpf/test_run.c:989
 bpf_prog_test_run kernel/bpf/syscall.c:3377 [inline]
 __sys_bpf+0xdf2/0x4a50 kernel/bpf/syscall.c:4679
 SYSC_bpf kernel/bpf/syscall.c:4765 [inline]
 SyS_bpf+0x26/0x50 kernel/bpf/syscall.c:4763
 do_syscall_64+0x21a/0x3e0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Fixes: 1c19499825 ("bpf: introduce frags support to bpf_prog_test_run_xdp()")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20220204235849.14658-1-sdf@google.com
2022-02-07 18:26:13 -08:00
Eric Dumazet
7d9b1b578d ip6mr: fix use-after-free in ip6mr_sk_done()
Apparently addrconf_exit_net() is called before igmp6_net_exit()
and ndisc_net_exit() at netns dismantle time:

 net_namespace: call ip6table_mangle_net_exit()
 net_namespace: call ip6_tables_net_exit()
 net_namespace: call ipv6_sysctl_net_exit()
 net_namespace: call ioam6_net_exit()
 net_namespace: call seg6_net_exit()
 net_namespace: call ping_v6_proc_exit_net()
 net_namespace: call tcpv6_net_exit()
 ip6mr_sk_done sk=ffffa354c78a74c0
 net_namespace: call ipv6_frags_exit_net()
 net_namespace: call addrconf_exit_net()
 net_namespace: call ip6addrlbl_net_exit()
 net_namespace: call ip6_flowlabel_net_exit()
 net_namespace: call ip6_route_net_exit_late()
 net_namespace: call fib6_rules_net_exit()
 net_namespace: call xfrm6_net_exit()
 net_namespace: call fib6_net_exit()
 net_namespace: call ip6_route_net_exit()
 net_namespace: call ipv6_inetpeer_exit()
 net_namespace: call if6_proc_net_exit()
 net_namespace: call ipv6_proc_exit_net()
 net_namespace: call udplite6_proc_exit_net()
 net_namespace: call raw6_exit_net()
 net_namespace: call igmp6_net_exit()
 ip6mr_sk_done sk=ffffa35472b2a180
 ip6mr_sk_done sk=ffffa354c78a7980
 net_namespace: call ndisc_net_exit()
 ip6mr_sk_done sk=ffffa35472b2ab00
 net_namespace: call ip6mr_net_exit()
 net_namespace: call inet6_net_exit()

This was fine because ip6mr_sk_done() would not reach the point decreasing
net->ipv6.devconf_all->mc_forwarding until my patch in ip6mr_sk_done().

To fix this without changing struct pernet_operations ordering,
we can clear net->ipv6.devconf_dflt and net->ipv6.devconf_all
when they are freed from addrconf_exit_net()

BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
Read of size 4 at addr ffff88801ff08688 by task kworker/u4:4/963

CPU: 0 PID: 963 Comm: kworker/u4:4 Not tainted 5.17.0-rc2-syzkaller-00650-g5a8fb33e5305 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 print_address_description.constprop.0.cold+0x8d/0x336 mm/kasan/report.c:255
 __kasan_report mm/kasan/report.c:442 [inline]
 kasan_report.cold+0x83/0xdf mm/kasan/report.c:459
 check_region_inline mm/kasan/generic.c:183 [inline]
 kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 ip6mr_sk_done+0x11b/0x410 net/ipv6/ip6mr.c:1578
 rawv6_close+0x58/0x80 net/ipv6/raw.c:1201
 inet_release+0x12e/0x280 net/ipv4/af_inet.c:428
 inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:478
 __sock_release net/socket.c:650 [inline]
 sock_release+0x87/0x1b0 net/socket.c:678
 inet_ctl_sock_destroy include/net/inet_common.h:65 [inline]
 igmp6_net_exit+0x6b/0x170 net/ipv6/mcast.c:3173
 ops_exit_list+0xb0/0x170 net/core/net_namespace.c:168
 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:600
 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307
 worker_thread+0x657/0x1110 kernel/workqueue.c:2454
 kthread+0x2e9/0x3a0 kernel/kthread.c:377
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Fixes: f2f2325ec7 ("ip6mr: ip6mr_sk_done() can exit early in common cases")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 12:07:45 +00:00
Tom Rix
0812beb705 caif: cleanup double word in comment
Replace the second 'so' with 'free'.

Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 12:06:54 +00:00
Menglong Dong
08d4c0370c net: udp: use kfree_skb_reason() in __udp_queue_rcv_skb()
Replace kfree_skb() with kfree_skb_reason() in __udp_queue_rcv_skb().
Following new drop reasons are introduced:

SKB_DROP_REASON_SOCKET_RCVBUFF
SKB_DROP_REASON_PROTO_MEM

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Menglong Dong
1379a92d38 net: udp: use kfree_skb_reason() in udp_queue_rcv_one_skb()
Replace kfree_skb() with kfree_skb_reason() in udp_queue_rcv_one_skb().

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Menglong Dong
10580c4791 net: ipv4: use kfree_skb_reason() in ip_protocol_deliver_rcu()
Replace kfree_skb() with kfree_skb_reason() in ip_protocol_deliver_rcu().
Following new drop reasons are introduced:

SKB_DROP_REASON_XFRM_POLICY
SKB_DROP_REASON_IP_NOPROTO

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Menglong Dong
c1f166d1f7 net: ipv4: use kfree_skb_reason() in ip_rcv_finish_core()
Replace kfree_skb() with kfree_skb_reason() in ip_rcv_finish_core(),
following drop reasons are introduced:

SKB_DROP_REASON_IP_RPFILTER
SKB_DROP_REASON_UNICAST_IN_L2_MULTICAST

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Menglong Dong
33cba42985 net: ipv4: use kfree_skb_reason() in ip_rcv_core()
Replace kfree_skb() with kfree_skb_reason() in ip_rcv_core(). Three new
drop reasons are introduced:

SKB_DROP_REASON_OTHERHOST
SKB_DROP_REASON_IP_CSUM
SKB_DROP_REASON_IP_INHDR

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Menglong Dong
2df3041ba3 net: netfilter: use kfree_drop_reason() for NF_DROP
Replace kfree_skb() with kfree_skb_reason() in nf_hook_slow() when
skb is dropped by reason of NF_DROP. Following new drop reasons
are introduced:

SKB_DROP_REASON_NETFILTER_DROP

Signed-off-by: Menglong Dong <imagedong@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-07 11:18:49 +00:00
Eric Dumazet
9c1be1935f net: initialize init_net earlier
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]

f8c46cb390 ("netns: do not call pernet ops for not yet set up init_net namespace")
b5082df801 ("net: Initialise init_net.count to 1")
734b65417b ("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 <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-06 11:04:29 +00:00
Juhee Kang
4acc45db71 net: hsr: use hlist_head instead of list_head for mac addresses
Currently, HSR manages mac addresses of known HSR nodes by using list_head.
It takes a lot of time when there are a lot of registered nodes due to
finding specific mac address nodes by using linear search. We can be
reducing the time by using hlist. Thus, this patch moves list_head to
hlist_head for mac addresses and this allows for further improvement of
network performance.

    Condition: registered 10,000 known HSR nodes
    Before:
    # iperf3 -c 192.168.10.1 -i 1 -t 10
    Connecting to host 192.168.10.1, port 5201
    [  5] local 192.168.10.2 port 59442 connected to 192.168.10.1 port 5201
    [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
    [  5]   0.00-1.49   sec  3.75 MBytes  21.1 Mbits/sec    0    158 KBytes
    [  5]   1.49-2.05   sec  1.25 MBytes  18.7 Mbits/sec    0    166 KBytes
    [  5]   2.05-3.06   sec  2.44 MBytes  20.3 Mbits/sec   56   16.9 KBytes
    [  5]   3.06-4.08   sec  1.43 MBytes  11.7 Mbits/sec   11   38.0 KBytes
    [  5]   4.08-5.00   sec   951 KBytes  8.49 Mbits/sec    0   56.3 KBytes

    After:
    # iperf3 -c 192.168.10.1 -i 1 -t 10
    Connecting to host 192.168.10.1, port 5201
    [  5] local 192.168.10.2 port 36460 connected to 192.168.10.1 port 5201
    [ ID] Interval           Transfer     Bitrate         Retr  Cwnd
    [  5]   0.00-1.00   sec  7.39 MBytes  62.0 Mbits/sec    3    130 KBytes
    [  5]   1.00-2.00   sec  5.06 MBytes  42.4 Mbits/sec   16    113 KBytes
    [  5]   2.00-3.00   sec  8.58 MBytes  72.0 Mbits/sec   42   94.3 KBytes
    [  5]   3.00-4.00   sec  7.44 MBytes  62.4 Mbits/sec    2    131 KBytes
    [  5]   4.00-5.07   sec  8.13 MBytes  63.5 Mbits/sec   38   92.9 KBytes

Signed-off-by: Juhee Kang <claudiajkang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-06 10:55:52 +00:00
Eric Dumazet
5a8fb33e53 skmsg: convert struct sk_msg_sg::copy to a bitmap
We have plans for increasing MAX_SKB_FRAGS, but sk_msg_sg::copy
is currently an unsigned long, limiting MAX_SKB_FRAGS to 30 on 32bit arches.

Convert it to a bitmap, as Jakub suggested.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-05 15:34:47 +00:00
Eric Dumazet
4c6c11ea0f net: refine dev_put()/dev_hold() debugging
We are still chasing some syzbot reports where we think a rogue dev_put()
is called with no corresponding prior dev_hold().
Unfortunately it eats a reference on dev->dev_refcnt taken by innocent
dev_hold_track(), meaning that the refcount saturation splat comes
too late to be useful.

Make sure that 'not tracked' dev_put() and dev_hold() better use
CONFIG_NET_DEV_REFCNT_TRACKER=y debug infrastructure:

Prior patch in the series allowed ref_tracker_alloc() and ref_tracker_free()
to be called with a NULL @trackerp parameter, and to use a separate refcount
only to detect too many put() even in the following case:

dev_hold_track(dev, tracker_1, GFP_ATOMIC);
 dev_hold(dev);
 dev_put(dev);
 dev_put(dev); // Should complain loudly here.
dev_put_track(dev, tracker_1); // instead of here

Add clarification about netdev_tracker_alloc() role.

v2: I replaced the dev_put() in linkwatch_do_dev()
    with __dev_put() because callers called netdev_tracker_free().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-02-05 15:22:45 +00:00