[PATCH] mpt3sas: add NULL check in _base_fault_reset_work()

[Sven Schnelle <svens@stackframe.org>]

My HP C8000 (an PA-RISC based system) crashed with an HPMC. That
triggered the HPMC handler in the kernel, and i got a crash in
_base_fault_reset_work() from mpt3sas. It looks like this function
calls ioc->schedule_dead_ioc_flush_running_cmds() without checking
whether there's actually a function set, so it dereferences a NULL
pointer on that system. The c8000 actually uses the mptspi driver
instead of mpt3sas which doesn't seem to set this handler.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
---
Disclaimer: I have no idea about the inner workings of the MPT Fusion drivers.
So this might be completely wrong.

 drivers/message/fusion/mptbase.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/message/fusion/mptbase.c b/drivers/message/fusion/mptbase.c
index 7f7abc9069f7..38f5aa43b457 100644
--- a/drivers/message/fusion/mptbase.c
+++ b/drivers/message/fusion/mptbase.c
@@ -381,7 +381,8 @@ mpt_fault_reset_work(struct work_struct *work)
 		 * since dead ioc will never return any command back from HW.
 		 */
 		hd = shost_priv(ioc->sh);
-		ioc->schedule_dead_ioc_flush_running_cmds(hd);
+		if (ioc->schedule_dead_ioc_flush_running_cmds)
+			ioc->schedule_dead_ioc_flush_running_cmds(hd);
 
 		/*Remove the Dead Host */
 		p = kthread_run(mpt_remove_dead_ioc_func, ioc,
-- 
2.33.0