Re: [PATCH 8/8] scsi: ufs: Check for completion from the timeout handler

Bart Van Assche <bvanassche@xxxxxxx> · Fri, 21 Jun 2024 10:23:32 -0700

On 6/20/24 11:54 PM, Peter Wang (王信友) wrote:
   Unable to handle kernel NULL pointer dereference at virtual address
0000000000000194
   pc : [0xffffffddd7a79bf8] blk_mq_unique_tag+0x8/0x14
   lr : [0xffffffddd6155b84] ufshcd_mcq_req_to_hwq+0x1c/0x40
[ufs_mediatek_mod_ise]
    do_mem_abort+0x58/0x118
    el1_abort+0x3c/0x5c
    el1h_64_sync_handler+0x54/0x90
    el1h_64_sync+0x68/0x6c
    blk_mq_unique_tag+0x8/0x14
    ufshcd_err_handler+0xae4/0xfa8 [ufs_mediatek_mod_ise]
    process_one_work+0x208/0x4fc
    worker_thread+0x228/0x438
    kthread+0x104/0x1d4
    ret_from_fork+0x10/0x20

Hi Peter,

The above backtrace can only occur with MCQ enabled. The backtrace I
posted was triggered on a system with a UFSHCI 3.0 controller (no MCQ).
So I think that the backtraces have different root causes and hence that
different patches are required to fix both crashes.

Thanks,

Bart.