CVE-2021-47622

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> scsi: ufs: Fix a deadlock in the error handler<br /> <br /> The following deadlock has been observed on a test setup:<br /> <br /> - All tags allocated<br /> <br /> - The SCSI error handler calls ufshcd_eh_host_reset_handler()<br /> <br /> - ufshcd_eh_host_reset_handler() queues work that calls<br /> ufshcd_err_handler()<br /> <br /> - ufshcd_err_handler() locks up as follows:<br /> <br /> Workqueue: ufs_eh_wq_0 ufshcd_err_handler.cfi_jt<br /> Call trace:<br /> __switch_to+0x298/0x5d8<br /> __schedule+0x6cc/0xa94<br /> schedule+0x12c/0x298<br /> blk_mq_get_tag+0x210/0x480<br /> __blk_mq_alloc_request+0x1c8/0x284<br /> blk_get_request+0x74/0x134<br /> ufshcd_exec_dev_cmd+0x68/0x640<br /> ufshcd_verify_dev_init+0x68/0x35c<br /> ufshcd_probe_hba+0x12c/0x1cb8<br /> ufshcd_host_reset_and_restore+0x88/0x254<br /> ufshcd_reset_and_restore+0xd0/0x354<br /> ufshcd_err_handler+0x408/0xc58<br /> process_one_work+0x24c/0x66c<br /> worker_thread+0x3e8/0xa4c<br /> kthread+0x150/0x1b4<br /> ret_from_fork+0x10/0x30<br /> <br /> Fix this lockup by making ufshcd_exec_dev_cmd() allocate a reserved<br /> request.