CVE-2023-52811: scsi: ibmvfc: Remove BUG_ON in the case of an empty event pool

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-05-21 · updated 2026-06-17
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: ibmvfc: Remove BUG_ON in the case of an empty event pool In practice the driver should never send more commands than are allocated to a queue's event pool. In the unlikely event that this happens, the code asserts a BUG_ON, and in the case that the kernel is not configured to crash on panic returns a junk event pointer from the empty event list causing things to spiral from there. This BUG_ON is a historical artifact of the ibmvfc driver first being upstreamed, and it is well known now that the use of BUG_ON is bad practice except in the most unrecoverable scenario. There is nothing about this scenario that prevents the driver from recovering and carrying on. Remove the BUG_ON in question from ibmvfc_get_event() and return a NULL pointer in the case of an empty event pool. Update all call sites to ibmvfc_get_event() to check for a NULL pointer and perfrom the appropriate failure or recovery action.

Affected products

Linux kernel: before 5.15.140; from 5.16 before 6.1.64; from 6.2 before 6.5.13; from 6.6 before 6.6.3 — fixed in 5.15.140, 6.1.64, 6.5.13, 6.6.3

How to fix

Upgrade to a fixed version: Linux kernel 5.15.140, 6.1.64, 6.5.13, 6.6.3. Check the vendor advisory for mitigations.

References

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