Commit 4356d0b6 authored May 27, 2011 by Ram Vepa Committed by Roland Dreier Jul 18, 2011

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>

parent 2df4f757

drivers/infiniband/hw/qib/qib_file_ops.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -1905,8 +1905,9 @@ int qib_set_uevent_bits(struct qib_pportdata *ppd, const int evtbit)
		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 @@ int qib_set_uevent_bits(struct qib_pportdata *ppd, const int evtbit)
		ret = 1;
		break;
		}
		spin_unlock(&ppd->dd->uctxt_lock);
		spin_unlock_irqrestore(&ppd->dd->uctxt_lock, flags);

		return ret;
		}