From ca7fb76e091f889cfda1287c07a9358f73832b39 Mon Sep 17 00:00:00 2001 From: James Smart Date: Mon, 10 Sep 2018 10:30:44 -0700 Subject: [PATCH] scsi: lpfc: Correct race with abort on completion path On io completion, the driver is taking an adapter wide lock and nulling the scsi command back pointer. The nulling of the back pointer is to signify the io was completed and the scsi_done() routine was called. However, the routine makes no check to see if the abort routine had done the same thing and possibly nulled the pointer. Thus it may doubly-complete the io. Make the following mods: - Check to make sure forward progress (call scsi_done()) only happens if the command pointer was non-null. - As the taking of the lock, which is adapter wide, is very costly on a system under load, null the pointer using an xchg operation rather than under lock. Signed-off-by: Dick Kennedy Signed-off-by: James Smart Signed-off-by: Martin K. Petersen --- drivers/scsi/lpfc/lpfc_scsi.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/scsi/lpfc/lpfc_scsi.c b/drivers/scsi/lpfc/lpfc_scsi.c index ef20d37..549eb58 100644 --- a/drivers/scsi/lpfc/lpfc_scsi.c +++ b/drivers/scsi/lpfc/lpfc_scsi.c @@ -4158,9 +4158,17 @@ lpfc_scsi_cmd_iocb_cmpl(struct lpfc_hba *phba, struct lpfc_iocbq *pIocbIn, } lpfc_scsi_unprep_dma_buf(phba, lpfc_cmd); - spin_lock_irqsave(&phba->hbalock, flags); - lpfc_cmd->pCmd = NULL; - spin_unlock_irqrestore(&phba->hbalock, flags); + /* If pCmd was set to NULL from abort path, do not call scsi_done */ + if (xchg(&lpfc_cmd->pCmd, NULL) == NULL) { + lpfc_printf_vlog(vport, KERN_INFO, LOG_FCP, + "0711 FCP cmd already NULL, sid: 0x%06x, " + "did: 0x%06x, oxid: 0x%04x\n", + vport->fc_myDID, + (pnode) ? pnode->nlp_DID : 0, + phba->sli_rev == LPFC_SLI_REV4 ? + lpfc_cmd->cur_iocbq.sli4_xritag : 0xffff); + return; + } /* The sdev is not guaranteed to be valid post scsi_done upcall. */ cmd->scsi_done(cmd); -- 2.7.4