Re: [PATCH v4 net-next] net: hsr: use hlist_head instead of list_head for mac addresses

[Eric Dumazet <eric.dumazet@gmail.com>]

On 2/6/22 03:10, patchwork-bot+netdevbpf@kernel.org wrote:
> Hello:
>
> This patch was applied to netdev/net-next.git (master)
> by David S. Miller <davem@davemloft.net>:
>
> On Sat,  5 Feb 2022 15:40:38 +0000 you wrote:
>> 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.
>>
>> [...]
> Here is the summary with links:
>    - [v4,net-next] net: hsr: use hlist_head instead of list_head for mac addresses
>      https://git.kernel.org/netdev/net-next/c/4acc45db7115
>
> You are awesome, thank you!


I think this patch has not been tested with CONFIG_PROVE_RCU=y


WARNING: suspicious RCU usage
5.17.0-rc3-next-20220207-syzkaller #0 Not tainted
-----------------------------
net/hsr/hsr_framereg.c:34 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
2 locks held by syz-executor.0/3603:
  #0: ffffffff8d3353a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock 
net/core/rtnetlink.c:72 [inline]
  #0: ffffffff8d3353a8 (rtnl_mutex){+.+.}-{3:3}, at: 
rtnetlink_rcv_msg+0x3be/0xb80 net/core/rtnetlink.c:5591
  #1: ffff88806e13d5f0 (&hsr->list_lock){+...}-{2:2}, at: spin_lock_bh 
include/linux/spinlock.h:359 [inline]
  #1: ffff88806e13d5f0 (&hsr->list_lock){+...}-{2:2}, at: 
hsr_create_self_node+0x225/0x650 net/hsr/hsr_framereg.c:108

stack backtrace:
CPU: 0 PID: 3603 Comm: syz-executor.0 Not tainted 
5.17.0-rc3-next-20220207-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS 
Google 01/01/2011
Call Trace:
  <TASK>
  __dump_stack lib/dump_stack.c:88 [inline]
  dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
  hsr_node_get_first+0x9b/0xb0 net/hsr/hsr_framereg.c:34
  hsr_create_self_node+0x22d/0x650 net/hsr/hsr_framereg.c:109
  hsr_dev_finalize+0x2c1/0x7d0 net/hsr/hsr_device.c:514
  hsr_newlink+0x315/0x730 net/hsr/hsr_netlink.c:102
  __rtnl_newlink+0x107c/0x1760 net/core/rtnetlink.c:3481
  rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3529
  rtnetlink_rcv_msg+0x413/0xb80 net/core/rtnetlink.c:5594
  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494
  netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline]
  netlink_unicast+0x539/0x7e0 net/netlink/af_netlink.c:1343
  netlink_sendmsg+0x904/0xe00 net/netlink/af_netlink.c:1919
  sock_sendmsg_nosec net/socket.c:705 [inline]
  sock_sendmsg+0xcf/0x120 net/socket.c:725
  __sys_sendto+0x21c/0x320 net/socket.c:2040
  __do_sys_sendto net/socket.c:2052 [inline]
  __se_sys_sendto net/socket.c:2048 [inline]
  __x64_sys_sendto+0xdd/0x1b0 net/socket.c:2048
  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