i2c: i801: fix hardware state machine corruption in error path
3Vexday Risk Score
Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.
ssvc Trackepss 0.1%
probabilidad de explotación
0.1%top 97% de las CVE
explotación observada
noninguna fuente lo reporta
In the Linux kernel, the following vulnerability has been resolved:
i2c: i801: fix hardware state machine corruption in error path
A severe livelock and subsequent Hung Task panic were observed in the
i2c-i801 driver during concurrent Fuzzing. The crash is caused by an
unconditional hardware register cleanup in the error handling path of
i801_access().
When i801_check_pre() fails (e.g., returning -EBUSY because the SMBus
controller is actively used by BIOS/ACPI), the kernel does not actually
acquire the hardware ownership. However, the code jumps to the 'out'
label and executes:
iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv));
This forcefully clears the INUSE_STS lock and resets the hardware status
flags without owning the controller. Doing so interrupts ongoing BIOS/ACPI
transactions and totally corrupts the SMBus hardware state machine.
Consequently, all subsequent i801_access() calls fail at the pre-check
stage, triggering an endless stream of "SMBus is busy, can't use it!"
error logs. Over a slow serial console, this printk flood monopolizes
the CPU (Console Livelock), starving other processes trying to acquire
the mmap_lock down_read semaphore, ultimately triggering the hung task
watchdog.
Fix this by moving the 'out' label below the hardware register cleanup.
If i801_check_pre() fails, we safely bypass the iowrite8() and only
release the software locks (pm_runtime and mutex), strictly adhering to
the rule of not releasing resources that were never acquired.
Productos afectados
Linux · LinuxReferencias
https://git.kernel.org/stable/c/00904687b9c5527d569d9a1ca72119823e735a61https://git.kernel.org/stable/c/10dd1a736d557e310a77117832874729a0175d57https://git.kernel.org/stable/c/2ef69871b313aa0f02182795f5e0f5aa455f203chttps://git.kernel.org/stable/c/bb5133a7d5f3fe5c387770e25f2e00e682ce11edhttps://git.kernel.org/stable/c/ef5a347532932f58748dad485c15039f5168c377