IB/qib: Fix potential deadlock with link down interrupt
There is a possibility of a deadlock due to the way locks are
acquired and released in qib_set_uevent_bits(). The function
qib_set_uevent_bits() is called in process context and it uses
spin_lock() and spin_unlock(). This same lock is acquired/released
in interrupt context which can lead to a deadlock when running on
the same cpu.
The fix is to replace spin_lock() and spin_unlock() with
spin_lock_irqsave() and spin_unlock_irqrestore() respectively in
qib_set_uevent_bits().
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c
index a94a460..2625303 100644
--- a/drivers/infiniband/hw/qib/qib_file_ops.c
+++ b/drivers/infiniband/hw/qib/qib_file_ops.c
@@ -1905,8 +1905,9 @@
struct qib_ctxtdata *rcd;
unsigned ctxt;
int ret = 0;
+ unsigned long flags;
- spin_lock(&ppd->dd->uctxt_lock);
+ spin_lock_irqsave(&ppd->dd->uctxt_lock, flags);
for (ctxt = ppd->dd->first_user_ctxt; ctxt < ppd->dd->cfgctxts;
ctxt++) {
rcd = ppd->dd->rcd[ctxt];
@@ -1925,7 +1926,7 @@
ret = 1;
break;
}
- spin_unlock(&ppd->dd->uctxt_lock);
+ spin_unlock_irqrestore(&ppd->dd->uctxt_lock, flags);
return ret;
}