Re: [PATCH net v2] net/mctp: publish the mctp_dev only after it is initialised

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@xxxxxxxxxx>:

On Tue, 22 Sep 2026 21:19:19 +0800 (CST) you wrote:
> From: Binbin Deng <18983559317@xxxxxxx>
> 
> mctp_add_dev() links the new mctp_dev into dev->mctp_ptr before mdev->dev
> is assigned, so a reader that picks the device up in that window
> dereferences a net_device pointer that is still NULL:
> 
> KASAN: null-ptr-deref in range [0x00000000000000b0-0x00000000000000b7]
> Call Trace:
>  <TASK>
>  ? __pfx_mctp_sendmsg (./include/linux/sockptr.h:49)
>  ? __pfx_mctp_dst_output (net/mctp/route.c:41)
>  ? selinux_socket_sendmsg (security/selinux/hooks.c:5278)
>  ____sys_sendmsg (net/socket.c:775 (discriminator 1) net/socket.c:790
>  (discriminator 1) net/socket.c:2684 (discriminator 1))
>  ? __pfx_____sys_sendmsg (net/socket.c:1131)
>  ? __pfx_copy_msghdr_from_user (net/socket.c:2590)
>  ? update_cfs_rq_load_avg (kernel/sched/fair.c:5478)
>  ___sys_sendmsg (net/socket.c:2738)
>  ? __pfx____sys_sendmsg (net/socket.c:2625)
>  ? perf_event_task_tick (./include/linux/rcupdate.h:838)
>  ? sched_tick (kernel/sched/core.c:5818)
>  ? clockevents_program_event (kernel/time/clockevents.c:372)
>  ? fdget (./include/linux/rcupdate.h:873 fs/file.c:1100)
>  __sys_sendmsg (net/socket.c:2770)
>  ? __pfx___sys_sendmsg (net/socket.c:2751)
>  do_syscall_64 (arch/x86/entry/syscall_64.c:63)
>  entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
>  </TASK>
> 
> [...]

Here is the summary with links:
  - [net,v2] net/mctp: publish the mctp_dev only after it is initialised
    https://git.kernel.org/netdev/net/c/aadf655e8ea9

You are awesome, thank you!
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