3.16.75-rc1 review patch. If anyone has any objections, please let me know.
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From: Jan Kara jack@suse.cz
commit 240b4cc8fd5db138b675297d4226ec46594d9b3b upstream.
Once we unlock adapter->hw_lock in pvscsi_queue_lck() nothing prevents just queued scsi_cmnd from completing and freeing the request. Thus cmd->cmnd[0] dereference can dereference already freed request leading to kernel crashes or other issues (which one of our customers observed). Store cmd->cmnd[0] in a local variable before unlocking adapter->hw_lock to fix the issue.
Signed-off-by: Jan Kara jack@suse.cz Reviewed-by: Ewan D. Milne emilne@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/scsi/vmw_pvscsi.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/scsi/vmw_pvscsi.c +++ b/drivers/scsi/vmw_pvscsi.c @@ -754,6 +754,7 @@ static int pvscsi_queue_lck(struct scsi_ struct pvscsi_adapter *adapter = shost_priv(host); struct pvscsi_ctx *ctx; unsigned long flags; + unsigned char op;
spin_lock_irqsave(&adapter->hw_lock, flags);
@@ -766,13 +767,14 @@ static int pvscsi_queue_lck(struct scsi_ }
cmd->scsi_done = done; + op = cmd->cmnd[0];
dev_dbg(&cmd->device->sdev_gendev, - "queued cmd %p, ctx %p, op=%x\n", cmd, ctx, cmd->cmnd[0]); + "queued cmd %p, ctx %p, op=%x\n", cmd, ctx, op);
spin_unlock_irqrestore(&adapter->hw_lock, flags);
- pvscsi_kick_io(adapter, cmd->cmnd[0]); + pvscsi_kick_io(adapter, op);
return 0; }