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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [BUG] scsi: lpfc: possible ABBA deadlock
To:     james.smart@broadcom.com, dick.kennedy@broadcom.com,
        jejb@linux.ibm.com, martin.petersen@oracle.com,
        linux-scsi@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>
Message-ID: <652256c8-6fce-a506-76a9-e1502a5ff82e@gmail.com>
Date:   Thu, 15 Jul 2021 18:37:55 +0800
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Hello,

I find there is a possible ABBA deadlock in the lpfc driver in Linux 5.10:

In lpfc_nvmet_unsol_fcp_issue_abort():
3502:     spin_lock_irqsave(&ctxp->ctxlock, flags);
3504: spin_lock(&phba->sli4_hba.abts_nvmet_buf_list_lock);

In lpfc_sli4_nvmet_xri_aborted():
1787: spin_lock(&phba->sli4_hba.abts_nvmet_buf_list_lock);
1794:     spin_lock(&ctxp->ctxlock);

When lpfc_nvmet_unsol_fcp_issue_abort() and 
lpfc_sli4_nvmet_xri_aborted() are concurrently executed, the deadlock 
can occur.

I am not quite sure whether this possible deadlock is real and how to 
fix it if it is real.
Any feedback would be appreciated, thanks :)


Best wishes,
Jia-Ju Bai