[PATCH 0/3] scsi: infinite guest hangs with scsi-disk

[Hannes Reinecke]

Hi all,

one of our customers reported an infinite guest hang following an FC link loss  
when using scsi-disk.
Problem is that scsi-disk issues SG_IO command with a timeout of UINT_MAX, 
which essentially signals
'no timeout' to the host kernel. So if the command gets lost eg during an 
unexpected link loss the
HBA driver will never attempt to abort or return the command. Hence the guest 
will hang forever, and
the only way to resolve things is to reboot the host.

To solve it this patchset adds an 'io_timeout' parameter to scsi-disk and 
scsi-generic, which allows
the admin to specify a command timeout for SG_IO request. It is initialized to 
30 seconds to avoid the
infinite hang as mentioned above.

As usual, comments and reviews are welcome.

Hannes Reinecke (3):
  virtio-scsi: trace events
  scsi: make io_timeout configurable
  scsi: add tracing for SG_IO commands

 hw/scsi/scsi-disk.c    |  9 ++++++---
 hw/scsi/scsi-generic.c | 25 ++++++++++++++++++-------
 hw/scsi/trace-events   | 13 +++++++++++++
 hw/scsi/virtio-scsi.c  | 30 +++++++++++++++++++++++++++++-
 include/hw/scsi/scsi.h |  4 +++-
 5 files changed, 69 insertions(+), 12 deletions(-)

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2.16.4