<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-dev/net/hsr, branch master</title>
<subtitle>Linux kernel development work - see feature branches</subtitle>
<id>https://git.zx2c4.com/linux-dev/atom/net/hsr?h=master</id>
<link rel='self' href='https://git.zx2c4.com/linux-dev/atom/net/hsr?h=master'/>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/'/>
<updated>2022-10-19T02:18:27Z</updated>
<entry>
<title>net: hsr: avoid possible NULL deref in skb_clone()</title>
<updated>2022-10-19T02:18:27Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-10-17T16:59:28Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=d8b57135fd9ffe9a5b445350a686442a531c5339'/>
<id>urn:sha1:d8b57135fd9ffe9a5b445350a686442a531c5339</id>
<content type='text'>
syzbot got a crash [1] in skb_clone(), caused by a bug
in hsr_get_untagged_frame().

When/if create_stripped_skb_hsr() returns NULL, we must
not attempt to call skb_clone().

While we are at it, replace a WARN_ONCE() by netdev_warn_once().

[1]
general protection fault, probably for non-canonical address 0xdffffc000000000f: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000078-0x000000000000007f]
CPU: 1 PID: 754 Comm: syz-executor.0 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:skb_clone+0x108/0x3c0 net/core/skbuff.c:1641
Code: 93 02 00 00 49 83 7c 24 28 00 0f 85 e9 00 00 00 e8 5d 4a 29 fa 4c 8d 75 7e 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 &lt;0f&gt; b6 04 02 4c 89 f2 83 e2 07 38 d0 7f 08 84 c0 0f 85 9e 01 00 00
RSP: 0018:ffffc90003ccf4e0 EFLAGS: 00010207

RAX: dffffc0000000000 RBX: ffffc90003ccf5f8 RCX: ffffc9000c24b000
RDX: 000000000000000f RSI: ffffffff8751cb13 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000000000f0 R09: 0000000000000140
R10: fffffbfff181d972 R11: 0000000000000000 R12: ffff888161fc3640
R13: 0000000000000a20 R14: 000000000000007e R15: ffffffff8dc5f620
FS: 00007feb621e4700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007feb621e3ff8 CR3: 00000001643a9000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
&lt;TASK&gt;
hsr_get_untagged_frame+0x4e/0x610 net/hsr/hsr_forward.c:164
hsr_forward_do net/hsr/hsr_forward.c:461 [inline]
hsr_forward_skb+0xcca/0x1d50 net/hsr/hsr_forward.c:623
hsr_handle_frame+0x588/0x7c0 net/hsr/hsr_slave.c:69
__netif_receive_skb_core+0x9fe/0x38f0 net/core/dev.c:5379
__netif_receive_skb_one_core+0xae/0x180 net/core/dev.c:5483
__netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5599
netif_receive_skb_internal net/core/dev.c:5685 [inline]
netif_receive_skb+0x12f/0x8d0 net/core/dev.c:5744
tun_rx_batched+0x4ab/0x7a0 drivers/net/tun.c:1544
tun_get_user+0x2686/0x3a00 drivers/net/tun.c:1995
tun_chr_write_iter+0xdb/0x200 drivers/net/tun.c:2025
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x9e9/0xdd0 fs/read_write.c:584
ksys_write+0x127/0x250 fs/read_write.c:637
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+0x63/0xcd

Fixes: f266a683a480 ("net/hsr: Better frame dispatch")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/r/20221017165928.2150130-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>genetlink: start to validate reserved header bytes</title>
<updated>2022-08-29T11:47:15Z</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2022-08-25T00:18:30Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=9c5d03d362519f36cd551aec596388f895c93d2d'/>
<id>urn:sha1:9c5d03d362519f36cd551aec596388f895c93d2d</id>
<content type='text'>
We had historically not checked that genlmsghdr.reserved
is 0 on input which prevents us from using those precious
bytes in the future.

One use case would be to extend the cmd field, which is
currently just 8 bits wide and 256 is not a lot of commands
for some core families.

To make sure that new families do the right thing by default
put the onus of opting out of validation on existing families.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Acked-by: Paul Moore &lt;paul@paul-moore.com&gt; (NetLabel)
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - gpl-2.0_30.RULE (part 2)</title>
<updated>2022-06-10T12:51:35Z</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2022-06-07T14:11:13Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=2aec85b26f39fa9e036c5872950c0ef9b479a1ec'/>
<id>urn:sha1:2aec85b26f39fa9e036c5872950c0ef9b479a1ec</id>
<content type='text'>
Based on the normalized pattern:

    this program is free software you can redistribute it and/or modify it
    under the terms of the gnu general public license as published by the
    free software foundation version 2  this program is distributed as is
    without any warranty of any kind whether express or implied without
    even the implied warranty of merchantability or fitness for a
    particular purpose see the gnu general public license for more details

extracted by the scancode license scanner the SPDX license identifier

    GPL-2.0-only

has been chosen to replace the boilerplate/reference.

Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: add per-cpu storage and net-&gt;core_stats</title>
<updated>2022-03-12T07:17:24Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-03-11T05:14:20Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=625788b5844511cf4c30cffa7fa0bc3a69cebc82'/>
<id>urn:sha1:625788b5844511cf4c30cffa7fa0bc3a69cebc82</id>
<content type='text'>
Before adding yet another possibly contended atomic_long_t,
it is time to add per-cpu storage for existing ones:
 dev-&gt;tx_dropped, dev-&gt;rx_dropped, and dev-&gt;rx_nohandler

Because many devices do not have to increment such counters,
allocate the per-cpu storage on demand, so that dev_get_stats()
does not have to spend considerable time folding zero counters.

Note that some drivers have abused these counters which
were supposed to be only used by core networking stack.

v4: should use per_cpu_ptr() in dev_get_stats() (Jakub)
v3: added a READ_ONCE() in netdev_core_stats_alloc() (Paolo)
v2: add a missing include (reported by kernel test robot &lt;lkp@intel.com&gt;)
    Change in netdev_core_stats_alloc() (Jakub)

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: jeffreyji &lt;jeffreyji@google.com&gt;
Reviewed-by: Brian Vazquez &lt;brianvv@google.com&gt;
Reviewed-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Acked-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Link: https://lore.kernel.org/r/20220311051420.2608812-1-eric.dumazet@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>flow_dissector: Add support for HSR</title>
<updated>2022-03-03T06:44:49Z</updated>
<author>
<name>Kurt Kanzenbach</name>
<email>kurt@linutronix.de</email>
</author>
<published>2022-02-28T19:58:56Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=bf08824a0f4776fc0626b82b6924fa1a5643eacb'/>
<id>urn:sha1:bf08824a0f4776fc0626b82b6924fa1a5643eacb</id>
<content type='text'>
Network drivers such as igb or igc call eth_get_headlen() to determine the
header length for their to be constructed skbs in receive path.

When running HSR on top of these drivers, it results in triggering BUG_ON() in
skb_pull(). The reason is the skb headlen is not sufficient for HSR to work
correctly. skb_pull() notices that.

For instance, eth_get_headlen() returns 14 bytes for TCP traffic over HSR which
is not correct. The problem is, the flow dissection code does not take HSR into
account. Therefore, add support for it.

Reported-by: Anthony Harivel &lt;anthony.harivel@linutronix.de&gt;
Signed-off-by: Kurt Kanzenbach &lt;kurt@linutronix.de&gt;
Link: https://lore.kernel.org/r/20220228195856.88187-1-kurt@linutronix.de
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: hsr: fix hsr build error when lockdep is not enabled</title>
<updated>2022-02-22T04:43:10Z</updated>
<author>
<name>Juhee Kang</name>
<email>claudiajkang@gmail.com</email>
</author>
<published>2022-02-20T15:32:50Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=a0b92e0514bb3c5e57c33fd720724a629f67e042'/>
<id>urn:sha1:a0b92e0514bb3c5e57c33fd720724a629f67e042</id>
<content type='text'>
In hsr, lockdep_is_held() is needed for rcu_dereference_bh_check().
But if lockdep is not enabled, lockdep_is_held() causes a build error:

    ERROR: modpost: "lockdep_is_held" [net/hsr/hsr.ko] undefined!

Thus, this patch solved by adding lockdep_hsr_is_held(). This helper
function calls the lockdep_is_held() when lockdep is enabled, and returns 1
if not defined.

Fixes: e7f27420681f ("net: hsr: fix suspicious RCU usage warning in hsr_node_get_first()")
Reported-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Signed-off-by: Juhee Kang &lt;claudiajkang@gmail.com&gt;
Link: https://lore.kernel.org/r/20220220153250.5285-1-claudiajkang@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
</content>
</entry>
<entry>
<title>net: hsr: fix suspicious RCU usage warning in hsr_node_get_first()</title>
<updated>2022-02-19T16:39:45Z</updated>
<author>
<name>Juhee Kang</name>
<email>claudiajkang@gmail.com</email>
</author>
<published>2022-02-19T15:29:59Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=e7f27420681f23e7e0f28beed38144058752112e'/>
<id>urn:sha1:e7f27420681f23e7e0f28beed38144058752112e</id>
<content type='text'>
When hsr_create_self_node() calls hsr_node_get_first(), the suspicious
RCU usage warning is occurred. The reason why this warning is raised is
the callers of hsr_node_get_first() use rcu_read_lock_bh() and
other different synchronization mechanisms. Thus, this patch solved by
replacing rcu_dereference() with rcu_dereference_bh_check().

The kernel test robot reports:
    [   50.083470][ T3596] =============================
    [   50.088648][ T3596] WARNING: suspicious RCU usage
    [   50.093785][ T3596] 5.17.0-rc3-next-20220208-syzkaller #0 Not tainted
    [   50.100669][ T3596] -----------------------------
    [   50.105513][ T3596] net/hsr/hsr_framereg.c:34 suspicious rcu_dereference_check() usage!
    [   50.113799][ T3596]
    [   50.113799][ T3596] other info that might help us debug this:
    [   50.113799][ T3596]
    [   50.124257][ T3596]
    [   50.124257][ T3596] rcu_scheduler_active = 2, debug_locks = 1
    [   50.132368][ T3596] 2 locks held by syz-executor.0/3596:
    [   50.137863][ T3596]  #0: ffffffff8d3357e8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3be/0xb80
    [   50.147470][ T3596]  #1: ffff88807ec9d5f0 (&amp;hsr-&gt;list_lock){+...}-{2:2}, at: hsr_create_self_node+0x225/0x650
    [   50.157623][ T3596]
    [   50.157623][ T3596] stack backtrace:
    [   50.163510][ T3596] CPU: 1 PID: 3596 Comm: syz-executor.0 Not tainted 5.17.0-rc3-next-20220208-syzkaller #0
    [   50.173381][ T3596] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
    [   50.183623][ T3596] Call Trace:
    [   50.186904][ T3596]  &lt;TASK&gt;
    [   50.189844][ T3596]  dump_stack_lvl+0xcd/0x134
    [   50.194640][ T3596]  hsr_node_get_first+0x9b/0xb0
    [   50.199499][ T3596]  hsr_create_self_node+0x22d/0x650
    [   50.204688][ T3596]  hsr_dev_finalize+0x2c1/0x7d0
    [   50.209669][ T3596]  hsr_newlink+0x315/0x730
    [   50.214113][ T3596]  ? hsr_dellink+0x130/0x130
    [   50.218789][ T3596]  ? rtnl_create_link+0x7e8/0xc00
    [   50.223803][ T3596]  ? hsr_dellink+0x130/0x130
    [   50.228397][ T3596]  __rtnl_newlink+0x107c/0x1760
    [   50.233249][ T3596]  ? rtnl_setlink+0x3c0/0x3c0
    [   50.238043][ T3596]  ? is_bpf_text_address+0x77/0x170
    [   50.243362][ T3596]  ? lock_downgrade+0x6e0/0x6e0
    [   50.248219][ T3596]  ? unwind_next_frame+0xee1/0x1ce0
    [   50.253605][ T3596]  ? entry_SYSCALL_64_after_hwframe+0x44/0xae
    [   50.259669][ T3596]  ? __sanitizer_cov_trace_cmp4+0x1c/0x70
    [   50.265423][ T3596]  ? is_bpf_text_address+0x99/0x170
    [   50.270819][ T3596]  ? kernel_text_address+0x39/0x80
    [   50.275950][ T3596]  ? __kernel_text_address+0x9/0x30
    [   50.281336][ T3596]  ? unwind_get_return_address+0x51/0x90
    [   50.286975][ T3596]  ? create_prof_cpu_mask+0x20/0x20
    [   50.292178][ T3596]  ? arch_stack_walk+0x93/0xe0
    [   50.297172][ T3596]  ? kmem_cache_alloc_trace+0x42/0x2c0
    [   50.302637][ T3596]  ? rcu_read_lock_sched_held+0x3a/0x70
    [   50.308194][ T3596]  rtnl_newlink+0x64/0xa0
    [   50.312524][ T3596]  ? __rtnl_newlink+0x1760/0x1760
    [   50.317545][ T3596]  rtnetlink_rcv_msg+0x413/0xb80
    [   50.322631][ T3596]  ? rtnl_newlink+0xa0/0xa0
    [   50.327159][ T3596]  netlink_rcv_skb+0x153/0x420
    [   50.331931][ T3596]  ? rtnl_newlink+0xa0/0xa0
    [   50.336436][ T3596]  ? netlink_ack+0xa80/0xa80
    [   50.341095][ T3596]  ? netlink_deliver_tap+0x1a2/0xc40
    [   50.346532][ T3596]  ? netlink_deliver_tap+0x1b1/0xc40
    [   50.351839][ T3596]  netlink_unicast+0x539/0x7e0
    [   50.356633][ T3596]  ? netlink_attachskb+0x880/0x880
    [   50.361750][ T3596]  ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70
    [   50.368003][ T3596]  ? __sanitizer_cov_trace_const_cmp8+0x1d/0x70
    [   50.374707][ T3596]  ? __phys_addr_symbol+0x2c/0x70
    [   50.379753][ T3596]  ? __sanitizer_cov_trace_cmp8+0x1d/0x70
    [   50.385568][ T3596]  ? __check_object_size+0x16c/0x4f0
    [   50.390859][ T3596]  netlink_sendmsg+0x904/0xe00
    [   50.395715][ T3596]  ? netlink_unicast+0x7e0/0x7e0
    [   50.400722][ T3596]  ? __sanitizer_cov_trace_const_cmp4+0x1c/0x70
    [   50.407003][ T3596]  ? netlink_unicast+0x7e0/0x7e0
    [   50.412119][ T3596]  sock_sendmsg+0xcf/0x120
    [   50.416548][ T3596]  __sys_sendto+0x21c/0x320
    [   50.421052][ T3596]  ? __ia32_sys_getpeername+0xb0/0xb0
    [   50.426427][ T3596]  ? lockdep_hardirqs_on_prepare+0x400/0x400
    [   50.432721][ T3596]  ? __context_tracking_exit+0xb8/0xe0
    [   50.438188][ T3596]  ? lock_downgrade+0x6e0/0x6e0
    [   50.443041][ T3596]  ? lock_downgrade+0x6e0/0x6e0
    [   50.447902][ T3596]  __x64_sys_sendto+0xdd/0x1b0
    [   50.452759][ T3596]  ? lockdep_hardirqs_on+0x79/0x100
    [   50.457964][ T3596]  ? syscall_enter_from_user_mode+0x21/0x70
    [   50.464150][ T3596]  do_syscall_64+0x35/0xb0
    [   50.468565][ T3596]  entry_SYSCALL_64_after_hwframe+0x44/0xae
    [   50.474452][ T3596] RIP: 0033:0x7f3148504e1c
    [   50.479052][ T3596] Code: fa fa ff ff 44 8b 4c 24 2c 4c 8b 44 24 20 89 c5 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 &lt;48&gt; 3d 00 f0 ff ff 77 34 89 ef 48 89 44 24 08 e8 20 fb ff ff 48 8b
    [   50.498926][ T3596] RSP: 002b:00007ffeab5f2ab0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
    [   50.507342][ T3596] RAX: ffffffffffffffda RBX: 00007f314959d320 RCX: 00007f3148504e1c
    [   50.515393][ T3596] RDX: 0000000000000048 RSI: 00007f314959d370 RDI: 0000000000000003
    [   50.523444][ T3596] RBP: 0000000000000000 R08: 00007ffeab5f2b04 R09: 000000000000000c
    [   50.531492][ T3596] R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
    [   50.539455][ T3596] R13: 00007f314959d370 R14: 0000000000000003 R15: 0000000000000000

Fixes: 4acc45db7115 ("net: hsr: use hlist_head instead of list_head for mac addresses")
Reported-by: Eric Dumazet &lt;eric.dumazet@gmail.com&gt;
Reported-and-tested-by: syzbot+f0eb4f3876de066b128c@syzkaller.appspotmail.com
Signed-off-by: Juhee Kang &lt;claudiajkang@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>net: hsr: use hlist_head instead of list_head for mac addresses</title>
<updated>2022-02-06T10:55:52Z</updated>
<author>
<name>Juhee Kang</name>
<email>claudiajkang@gmail.com</email>
</author>
<published>2022-02-05T15:40:38Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=4acc45db711586dadb98e681ccb93f29372907a2'/>
<id>urn:sha1:4acc45db711586dadb98e681ccb93f29372907a2</id>
<content type='text'>
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 &lt;claudiajkang@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>hsr: remove get_prp_lan_id()</title>
<updated>2022-01-27T13:53:27Z</updated>
<author>
<name>Jakub Kicinski</name>
<email>kuba@kernel.org</email>
</author>
<published>2022-01-26T19:11:01Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=0ab1e6d9a453459ce5104a3412e9c193608971bd'/>
<id>urn:sha1:0ab1e6d9a453459ce5104a3412e9c193608971bd</id>
<content type='text'>
get_prp_lan_id() has never been used.

Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
<entry>
<title>net: Write lock dev_base_lock without disabling bottom halves.</title>
<updated>2021-11-29T12:12:36Z</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2021-11-26T16:15:29Z</published>
<link rel='alternate' type='text/html' href='https://git.zx2c4.com/linux-dev/commit/?id=fd888e85fe6b661e78044dddfec0be5271afa626'/>
<id>urn:sha1:fd888e85fe6b661e78044dddfec0be5271afa626</id>
<content type='text'>
The writer acquires dev_base_lock with disabled bottom halves.
The reader can acquire dev_base_lock without disabling bottom halves
because there is no writer in softirq context.

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 (as in write_lock_bh()) and somewhere else with
enabled bottom halves (as by read_lock() in netstat_show()) followed by
disabling bottom halves (cxgb_get_stats() -&gt; t4_wr_mbox_meat_timeout()
-&gt; spin_lock_bh()). This is the reverse locking order.

All read_lock() invocation are from sysfs callback which are not invoked
from softirq context. Therefore there is no need to disable bottom
halves while acquiring a write lock.

Acquire the write lock of dev_base_lock without disabling bottom halves.

Reported-by: Pei Zhang &lt;pezhang@redhat.com&gt;
Reported-by: Luis Claudio R. Goncalves &lt;lgoncalv@redhat.com&gt;
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
</entry>
</feed>
