Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix double unregister of HCA_PORTS component

Clear hca_devcom_comp in device's private data after unregistering it in LAG teardown. Otherwise a slightly lagging second pass through mlx5_unload_one() might try to unregister it again and trip over use-after-free.

On s390 almost all PCI level recovery events trigger two passes through mxl5_unload_one() - one through the poll_health() method and one through mlx5_pci_err_detected() as callback from generic PCI error recovery. While testing PCI error recovery paths with more kernel debug features enabled, this issue reproducibly led to kernel panics with the following call chain:

Unable to handle kernel pointer dereference in virtual kernel address space Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6803 ESOP-2 FSI Fault in home space mode while using kernel ASCE. AS:00000000705c4007 R3:0000000000000024 Oops: 0038 ilc:3 [#1]SMP

CPU: 14 UID: 0 PID: 156 Comm: kmcheck Kdump: loaded Not tainted 6.18.0-20251130.rc7.git0.16131a59cab1.300.fc43.s390x+debug #1 PREEMPT

Krnl PSW : 0404e00180000000 0000020fc86aa1dc (__lock_acquire+0x5c/0x15f0) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 0000020f00000001 6b6b6b6b6b6b6c33 0000000000000000 0000000000000000 0000000000000000 0000000000000001 0000000000000000 0000000000000000 0000020fca28b820 0000000000000000 0000010…