In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: ufs-qcom: Fix ESI null pointer dereference
ESI/MSI is a performance optimization feature that provides dedicated interrupts per MCQ hardware queue. This is optional feature and UFS MCQ should work with and without ESI feature.
Commit e46a28cea29a (scsi: ufs: qcom: Remove the MSI descriptor abuse) brings a regression in ESI (Enhanced System Interrupt) configuration that causes a null pointer dereference when Platform MSI allocation fails.
The issue occurs in when platform_device_msi_init_and_alloc_irqs() in ufs_qcom_config_esi() fails (returns -EINVAL) but the current code uses __free() macro for automatic cleanup free MSI resources that were never successfully allocated.
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
Call trace: mutex_lock+0xc/0x54 (P) platform_device_msi_free_irqs_all+0x1c/0x40 ufs_qcom_config_esi+0x1d0/0x220 [ufs_qcom] ufshcd_config_mcq+0x28/0x104 ufshcd_init+0xa3c/0xf40 ufshcd_pltfrm_init+0x504/0x7d4 ufs_qcom_probe+0x20/0x58 [ufs_qcom]
Fix by restructuring the ESI configuration to try MSI allocation first, before any other resource allocation and instead use explicit cleanup instead of __free() macro to avoid cleanup of unallocated resources.
Tested on SM8750 platform with MCQ enabled, both with and without Platform ESI support.