From f94fd45c75ee6b72e96b7e368aefc60d45d3d60d 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 [ Upstream commit ca7fb76e091f889cfda1287c07a9358f73832b39 ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- 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 5c7858e735c9..200b5bca1f5f 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); -- 2.11.0