On March 2, 2017 10:23:24 AM PST, Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> wrote: >On Thu, 2 Mar 2017 14:25:14 +0100 >Hannes Reinecke <hare@xxxxxxx> wrote: > >> On 03/02/2017 02:40 AM, Stephen Hemminger wrote: >> > On Thu, 2 Mar 2017 01:56:15 +0100 >> > Christoph Hellwig <hch@xxxxxx> wrote: >> > >> >> On Thu, Mar 02, 2017 at 01:01:35AM +0100, Christoph Hellwig wrote: > >> >>> On Wed, Mar 01, 2017 at 07:54:12AM -0800, Stephen Hemminger >wrote: >> >>>>> > http://git.infradead.org/users/hch/block.git/commitdiff/148cff67b401e2229c076c0ea418712654be77e4 > >> >>>> >> >>>> It appears that is already in the code I am testing in >linux-next... >> >>> >> >>> It's in -next now, but it wasn't at the time you reported the >bug. >> >>> >> >>> And it would sortof explain the bug if the INQUIRY data is >correct >> >>> in the scatterlist, but we ignore it, given that scsi_probe_lun >> >>> ignores the result based on sense data. >> >>> >> >>> Can you check what happens with the horrible hack below: >> >> >> >> Strike that - we're checking result later, so this can't be the >case. >> >> >> >> Now the other interesting thing is the memset in __scsi_exectute, >> >> which looks very suspicious. Try the following please: >> >> >> >> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c >> >> index 3e32dc954c3c..22f4fb550561 100644 >> >> --- a/drivers/scsi/scsi_lib.c >> >> +++ b/drivers/scsi/scsi_lib.c >> >> @@ -253,7 +253,8 @@ static int __scsi_execute(struct scsi_device >*sdev, const unsigned char *cmd, >> >> * and prevent security leaks by zeroing out the excess data. >> >> */ >> >> if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen)) >> >> - memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); >> >> +// memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len); >> >> + printk_ratelimited("%s: got resid %d\n", __func__, >rq->resid_len); >> >> >> >> if (resid) >> >> *resid = rq->resid_len; >> > >> > >> > Still fails but does print resid on some of the later INQUIRY >commands (not the initial one). >> > >> Can you test what happens if you blank out the storvsc_drv >workaround: >> >> diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c >> index 585e54f..c36f42d 100644 >> --- a/drivers/scsi/storvsc_drv.c >> +++ b/drivers/scsi/storvsc_drv.c >> @@ -1060,13 +1060,13 @@ static void storvsc_on_io_completion(struct >> storvsc_device *stor_device, >> * We do this so we can distinguish truly fatal failues >> * (srb status == 0x4) and off-line the device in that case. >> */ >> - >> +#if 0 >> if ((stor_pkt->vm_srb.cdb[0] == INQUIRY) || >> (stor_pkt->vm_srb.cdb[0] == MODE_SENSE)) { >> vstor_packet->vm_srb.scsi_status = 0; >> vstor_packet->vm_srb.srb_status = >SRB_STATUS_SUCCESS; >> } >> - >> +#endif >> >> /* Copy over the status...etc */ >> stor_pkt->vm_srb.scsi_status = >vstor_packet->vm_srb.scsi_status; >> >> It might thappen that we're fail to interpret the 'Device not >present' >> status correctly (which will happen for non-connected DVDs) causing >the >> SCSI stack to make incorrect decisions later on. >> >> Cheers, >> >> Hannes > >There are several oddities about the host SCSI interface that I see: > 1. The host bus seems to report up to 6 devices even though only 2 are > present (Disk and CDROM). >2. The CDROM emulation doesn't report the same status as a real device. > 3. The host emulation of SCSI doesn't support all the page codes which > is why there is the hack. > >But as James said, these don't appear to be related to the failure >because >the code worked before and only in post 4.11 merege is there a problem. Your wait for the hang trace is the most suggestive. It says we're waiting for a partition read to the spurious device. Previously this would have failed or timed out, so this seems to be the root cause. James -- Sent from my Android device with K-9 Mail. Please excuse my brevity.
