linux-kernel - Re: [PATCH] ibmvfc: Fix invalid state machine BUG

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Message-Id: <161853823946.16006.3766095104419488377.b4-ty@oracle.com>
Date:   Thu, 15 Apr 2021 22:51:21 -0400
From:   "Martin K. Petersen" <martin.petersen@...cle.com>
To:     james.bottomley@...senpartnership.com,
        Tyrel Datwyler <tyreld@...ux.ibm.com>
Cc:     "Martin K . Petersen" <martin.petersen@...cle.com>,
        linux-kernel@...r.kernel.org,
        Brian King <brking@...ux.vnet.ibm.com>,
        linux-scsi@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        brking@...ux.ibm.com
Subject: Re: [PATCH] ibmvfc: Fix invalid state machine BUG_ON

On Mon, 12 Apr 2021 18:10:09 -0600, Tyrel Datwyler wrote:

> This fixes an issue hitting the BUG_ON in ibmvfc_do_work. When
> going through a host action of IBMVFC_HOST_ACTION_RESET,
> we change the action to IBMVFC_HOST_ACTION_TGT_DEL,
> then drop the host lock, and reset the CRQ, which changes
> the host state to IBMVFC_NO_CRQ. If, prior to setting the
> host state to IBMVFC_NO_CRQ, ibmvfc_init_host is called,
> it can then end up changing the host action to IBMVFC_HOST_ACTION_INIT.
> If we then change the host state to IBMVFC_NO_CRQ, we will then
> hit the BUG_ON. This patch makes a couple of changes to avoid this.
> It leaves the host action to be IBMVFC_HOST_ACTION_RESET
> or IBMVFC_HOST_ACTION_REENABLE until after we drop the host
> lock and reset or reenable the CRQ. It also hardens the
> host state machine to ensure we cannot leave the reset / reenable
> state until we've finished processing the reset or reenable.

Applied to 5.13/scsi-queue, thanks!

[1/1] ibmvfc: Fix invalid state machine BUG_ON
      https://git.kernel.org/mkp/scsi/c/15cfef8623a4

-- 
Martin K. Petersen	Oracle Linux Engineering