From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35694) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eMXlb-0001eG-1s for qemu-devel@nongnu.org; Wed, 06 Dec 2017 06:21:32 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eMXlW-0002Rm-OY for qemu-devel@nongnu.org; Wed, 06 Dec 2017 06:21:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34398) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eMXlW-0002Qb-IC for qemu-devel@nongnu.org; Wed, 06 Dec 2017 06:21:26 -0500 From: P J P Date: Wed, 6 Dec 2017 16:51:16 +0530 Message-Id: <20171206112116.29413-1-ppandit@redhat.com> Subject: [Qemu-devel] [PATCH] scsi: check current request object before use List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Qemu Developers Cc: Paolo Bonzini , Zhangboxian , Prasad J Pandit From: Prasad J Pandit During a dma access, SCSIRequest object 'current_req' could be null, leading to a null pointer dereference. Add check to avoid it. Reported-by: Zhangboxian Signed-off-by: Prasad J Pandit --- hw/scsi/esp.c | 2 +- hw/scsi/scsi-bus.c | 3 +++ 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c index ee586e7d6c..0c6925a708 100644 --- a/hw/scsi/esp.c +++ b/hw/scsi/esp.c @@ -273,7 +273,7 @@ static void esp_do_dma(ESPState *s) s->ti_size += len; else s->ti_size -= len; - if (s->async_len == 0) { + if (s->current_req && s->async_len == 0) { scsi_req_continue(s->current_req); /* If there is still data to be read from the device then complete the DMA operation immediately. Otherwise defer diff --git a/hw/scsi/scsi-bus.c b/hw/scsi/scsi-bus.c index 977f7bce1f..ac64a239e9 100644 --- a/hw/scsi/scsi-bus.c +++ b/hw/scsi/scsi-bus.c @@ -1338,6 +1338,9 @@ void scsi_req_unref(SCSIRequest *req) will start the next chunk or complete the command. */ void scsi_req_continue(SCSIRequest *req) { + if (!req) { + return; + } if (req->io_canceled) { trace_scsi_req_continue_canceled(req->dev->id, req->lun, req->tag); return; -- 2.13.6