Linux Kernel UFS Error Handler Hang Vulnerability

A vulnerability in the Linux kernel's SCSI core UFS error handling can lead to a hang condition. The issue arises because the error handler's preparation function, 'ufshcd_err_handling_prepare()', calls 'ufshcd_rpm_get_sync()' to resume operations. However, this call can only succeed if the 'UFSHCD_EH_IN_PROGRESS' flag is not set, as the flag indicates that a SCSI command is already being processed. The error handler can get stuck if 'UFSHCD_EH_IN_PROGRESS' is set, preventing the command from being queued and causing a hang. The vulnerability has been addressed by modifying the error handling process to avoid this deadlock.

Impact

The vulnerability can cause a deadlock situation where the error handler gets stuck, unable to proceed with error recovery operations.