CVE-2024-35957

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

iommu/vt-d: Fix WARN_ON in iommu probe path

Commit 1a75cc710b95 ("iommu/vt-d: Use rbtree to track iommu probed devices") adds all devices probed by the iommu driver in a rbtree indexed by the source ID of each device. It assumes that each device has a unique source ID. This assumption is incorrect and the VT-d spec doesn't state this requirement either.

The reason for using a rbtree to track devices is to look up the device with PCI bus and devfunc in the paths of handling ATS invalidation time out error and the PRI I/O page faults. Both are PCI ATS feature related.

Only track the devices that have PCI ATS capabilities in the rbtree to avoid unnecessary WARN_ON in the iommu probe path. Otherwise, on some platforms below kernel splat will be displayed and the iommu probe results in failure.

WARNING: CPU: 3 PID: 166 at drivers/iommu/intel/iommu.c:158 inteliommuprobedevice+0x319/0xd90 Call Trace: <TASK> ? warn+0x7e/0x180 ? inteliommuprobedevice+0x319/0xd90 ? reportbug+0x1f8/0x200 ? handlebug+0x3c/0x70 ? excinvalidop+0x18/0x70 ? asmexcinvalidop+0x1a/0x20 ? inteliommuprobedevice+0x319/0xd90 ? debugmutexinit+0x37/0x50 _iommuprobedevice+0xf2/0x4f0 iommuprobedevice+0x22/0x70 iommubusnotifier+0x1e/0x40 notifiercallchain+0x46/0x150 blockingnotifiercallchain+0x42/0x60 busnotify+0x2f/0x50 deviceadd+0x5ed/0x7e0 platformdeviceadd+0xf5/0x240 mfdadddevices+0x3f9/0x500 ? preemptcountadd+0x4c/0xa0 ? upwrite+0xa2/0x1b0 ? _debugfscreatefile+0xe3/0x150 intellpssprobe+0x49f/0x5b0 ? pciconf1write+0xa3/0xf0 intellpsspciprobe+0xcf/0x110 [intellpsspci] pcideviceprobe+0x95/0x120 reallyprobe+0xd9/0x370 ? _pfxdriverattach+0x10/0x10 driverprobedevice+0x73/0x150 driverprobedevice+0x19/0xa0 _driverattach+0xb6/0x180 ? _pfxdriverattach+0x10/0x10 busforeachdev+0x77/0xd0 busadddriver+0x114/0x210 driverregister+0x5b/0x110 ? _pfxintellpsspcidriverinit+0x10/0x10 [intellpsspci] dooneinitcall+0x57/0x2b0 ? kmalloctrace+0x21e/0x280 ? doinitmodule+0x1e/0x210 doinitmodule+0x5f/0x210 loadmodule+0x1d37/0x1fc0 ? initmodulefromfile+0x86/0xd0 initmodulefromfile+0x86/0xd0 idempotentinitmodule+0x17c/0x230 _x64sysfinitmodule+0x56/0xb0 dosyscall64+0x6e/0x140 entrySYSCALL64afterhwframe+0x71/0x79