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Subject[PATCH 3.16.y-ckt 066/144] target: Fix virtual LUN=0 target_configure_device failure OOPs
Date
3.16.7-ckt10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Nicholas Bellinger <nab@linux-iscsi.org>

commit 5f7da044f8bc1cfb21c962edf34bd5699a76e7ae upstream.

This patch fixes a NULL pointer dereference triggered by a late
target_configure_device() -> alloc_workqueue() failure that results
in target_free_device() being called with DF_CONFIGURED already set,
which subsequently OOPses in destroy_workqueue() code.

Currently this only happens at modprobe target_core_mod time when
core_dev_setup_virtual_lun0() -> target_configure_device() fails,
and the explicit target_free_device() gets called.

To address this bug originally introduced by commit 0fd97ccf45, go
ahead and move DF_CONFIGURED to end of target_configure_device()
code to handle this special failure case.

Reported-by: Claudio Fleiner <cmf@daterainc.com>
Cc: Claudio Fleiner <cmf@daterainc.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
---
drivers/target/target_core_device.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index e205bdbe14b2..5478aca8f4e6 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -1591,8 +1591,6 @@ int target_configure_device(struct se_device *dev)
ret = dev->transport->configure_device(dev);
if (ret)
goto out;
- dev->dev_flags |= DF_CONFIGURED;
-
/*
* XXX: there is not much point to have two different values here..
*/
@@ -1654,6 +1652,8 @@ int target_configure_device(struct se_device *dev)
list_add_tail(&dev->g_dev_node, &g_device_list);
mutex_unlock(&g_device_mutex);

+ dev->dev_flags |= DF_CONFIGURED;
+
return 0;

out_free_alua:

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