[PATCH 3.10 57/70] SCSI: hpsa: fix a race in cmd_free/scsi_done

Greg Kroah-Hartman
2014-11-19T21:23:17Z

From: Tomas Henzl <thenzl@redhat.com>

commit 2cc5bfaf854463d9d1aa52091f60110fbf102a96 upstream.

When the driver calls scsi_done and after that frees it's internal
preallocated memory it can happen that a new job is enqueud before
the memory is freed. The allocation fails and the message
"cmd_alloc returned NULL" is shown.
Patch below fixes it by moving cmd->scsi_done after cmd_free.

Signed-off-by: Tomas Henzl <thenzl@redhat.com>
Acked-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Cc: Masoud Sharbiani <msharbiani@twitter.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/scsi/hpsa.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/scsi/hpsa.c
+++ b/drivers/scsi/hpsa.c
@@ -1206,8 +1206,8 @@ static void complete_scsi_command(struct
scsi_set_resid(cmd, ei->ResidualCnt);

if (ei->CommandStatus == 0) {
- cmd->scsi_done(cmd);
cmd_free(h, cp);
+ cmd->scsi_done(cmd);
return;
}

@@ -1380,8 +1380,8 @@ static void complete_scsi_command(struct
dev_warn(&h->pdev->dev, "cp %p returned unknown status %x\n",
cp, ei->CommandStatus);
}
- cmd->scsi_done(cmd);
cmd_free(h, cp);
+ cmd->scsi_done(cmd);
}

static void hpsa_pci_unmap(struct pci_dev *pdev,