CVE-2026-98814: nvme: fix command effects log lifetime for multipath heads
In the Linux kernel, the following vulnerability has been resolved:
nvme: fix command effects log lifetime for multipath heads
KASAN reported a use-after-free when an I/O passthrough command was sent through a multipath namespace head after the controller path that first created the head had been removed:
BUG: KASAN: slab-use-after-free in nvmecommandeffects+0x192/0x200 [nvmecore] Read of size 4 at addr ffff888141b14400 by task nvme/19811 nvmecommandeffects+0x192/0x200 [nvmecore] nvmecmdallowed+0x7e/0x1b0 [nvmecore] nvmeusercmd.constprop.0+0x1b5/0x450 [nvmecore] nvmensheadchrioctl+0xf4/0x2a0 [nvmecore]
Move the log cache to the subsystem, with one entry per command set. Both controllers and namespace heads hold subsystem references, keeping their log pointers valid until subsystem release.