Bug 2464360 (CVE-2026-43012) - CVE-2026-43012 kernel: net/mlx5: Fix switchdev mode rollback in case of failure
Summary: CVE-2026-43012 kernel: net/mlx5: Fix switchdev mode rollback in case of failure
Keywords:
Status: NEW
Alias: CVE-2026-43012
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-01 15:02 UTC by OSIDB Bzimport
Modified: 2026-05-01 16:22 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-05-01 15:02:15 UTC
In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix switchdev mode rollback in case of failure

If for some internal reason switchdev mode fails, we rollback to legacy
mode, before this patch, rollback will unregister the uplink netdev and
leave it unregistered causing the below kernel bug.

To fix this, we need to avoid netdev unregister by setting the proper
rollback flag 'MLX5_PRIV_FLAGS_SWITCH_LEGACY' to indicate legacy mode.

devlink (431) used greatest stack depth: 11048 bytes left
mlx5_core 0000:00:03.0: E-Switch: Disable: mode(LEGACY), nvfs(0), \
	necvfs(0), active vports(0)
mlx5_core 0000:00:03.0: E-Switch: Supported tc chains and prios offload
mlx5_core 0000:00:03.0: Loading uplink representor for vport 65535
mlx5_core 0000:00:03.0: mlx5_cmd_out_err:816:(pid 456): \
	QUERY_HCA_CAP(0x100) op_mod(0x0) failed, \
	status bad parameter(0x3), syndrome (0x3a3846), err(-22)
mlx5_core 0000:00:03.0 enp0s3np0 (unregistered): Unloading uplink \
	representor for vport 65535
 ------------[ cut here ]------------
kernel BUG at net/core/dev.c:12070!
Oops: invalid opcode: 0000 [#1] SMP NOPTI
CPU: 2 UID: 0 PID: 456 Comm: devlink Not tainted 6.16.0-rc3+ \
	#9 PREEMPT(voluntary)
RIP: 0010:unregister_netdevice_many_notify+0x123/0xae0
...
Call Trace:
[   90.923094]  unregister_netdevice_queue+0xad/0xf0
[   90.923323]  unregister_netdev+0x1c/0x40
[   90.923522]  mlx5e_vport_rep_unload+0x61/0xc6
[   90.923736]  esw_offloads_enable+0x8e6/0x920
[   90.923947]  mlx5_eswitch_enable_locked+0x349/0x430
[   90.924182]  ? is_mp_supported+0x57/0xb0
[   90.924376]  mlx5_devlink_eswitch_mode_set+0x167/0x350
[   90.924628]  devlink_nl_eswitch_set_doit+0x6f/0xf0
[   90.924862]  genl_family_rcv_msg_doit+0xe8/0x140
[   90.925088]  genl_rcv_msg+0x18b/0x290
[   90.925269]  ? __pfx_devlink_nl_pre_doit+0x10/0x10
[   90.925506]  ? __pfx_devlink_nl_eswitch_set_doit+0x10/0x10
[   90.925766]  ? __pfx_devlink_nl_post_doit+0x10/0x10
[   90.926001]  ? __pfx_genl_rcv_msg+0x10/0x10
[   90.926206]  netlink_rcv_skb+0x52/0x100
[   90.926393]  genl_rcv+0x28/0x40
[   90.926557]  netlink_unicast+0x27d/0x3d0
[   90.926749]  netlink_sendmsg+0x1f7/0x430
[   90.926942]  __sys_sendto+0x213/0x220
[   90.927127]  ? __sys_recvmsg+0x6a/0xd0
[   90.927312]  __x64_sys_sendto+0x24/0x30
[   90.927504]  do_syscall_64+0x50/0x1c0
[   90.927687]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[   90.927929] RIP: 0033:0x7f7d0363e047


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