From: Nathaniel Clark <Nathaniel.Clark@misrule.us>
Date: Tue, 23 Jul 2013 17:32:57 +0000 (-0400)
Subject: dmu_tx: Fix possible NULL pointer dereference
X-Git-Tag: zfs-0.6.2~25
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=7d63721118a82a29649a3d8ae4b4522afdad1449;p=zfs

dmu_tx: Fix possible NULL pointer dereference

dmu_tx_hold_object_impl can return NULL on error.  Check for this
condition prior to dereferencing pointer.  This can only occur if
the passed object was invalid or unallocated.

Signed-off-by: Nathaniel Clark <Nathaniel.Clark@misrule.us>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #1610
---

diff --git a/module/zfs/dmu_tx.c b/module/zfs/dmu_tx.c
index b0dc64f06..fd714135a 100644
--- a/module/zfs/dmu_tx.c
+++ b/module/zfs/dmu_tx.c
@@ -773,12 +773,13 @@ void
 dmu_tx_hold_space(dmu_tx_t *tx, uint64_t space)
 {
 	dmu_tx_hold_t *txh;
+
 	ASSERT(tx->tx_txg == 0);
 
 	txh = dmu_tx_hold_object_impl(tx, tx->tx_objset,
 	    DMU_NEW_OBJECT, THT_SPACE, space, 0);
-
-	txh->txh_space_towrite += space;
+	if (txh)
+		txh->txh_space_towrite += space;
 }
 
 int
@@ -1320,6 +1321,8 @@ dmu_tx_hold_spill(dmu_tx_t *tx, uint64_t object)
 
 	txh = dmu_tx_hold_object_impl(tx, tx->tx_objset, object,
 	    THT_SPILL, 0, 0);
+	if (txh == NULL)
+		return;
 
 	dn = txh->txh_dnode;