diff --git a/tests/runfiles/common.run b/tests/runfiles/common.run
index fd7885d51..c6b995d4e 100644
--- a/tests/runfiles/common.run
+++ b/tests/runfiles/common.run
@@ -717,6 +717,10 @@ tags = ['functional', 'direct']
 tests = ['exec_001_pos', 'exec_002_neg']
 tags = ['functional', 'exec']
 
+[tests/functional/failmode]
+tests = ['failmode_dmu_tx_wait', 'failmode_dmu_tx_continue']
+tags = ['functional', 'failmode']
+
 [tests/functional/fallocate]
 tests = ['fallocate_punch-hole']
 tags = ['functional', 'fallocate']
diff --git a/tests/zfs-tests/tests/Makefile.am b/tests/zfs-tests/tests/Makefile.am
index ee9d3b1d7..5a5008bfa 100644
--- a/tests/zfs-tests/tests/Makefile.am
+++ b/tests/zfs-tests/tests/Makefile.am
@@ -1528,6 +1528,10 @@ nobase_dist_datadir_zfs_tests_tests_SCRIPTS += \
 	functional/fadvise/cleanup.ksh \
 	functional/fadvise/fadvise_sequential.ksh \
 	functional/fadvise/setup.ksh \
+	functional/failmode/cleanup.ksh \
+	functional/failmode/failmode_dmu_tx_wait.ksh \
+	functional/failmode/failmode_dmu_tx_continue.ksh \
+	functional/failmode/setup.ksh \
 	functional/fallocate/cleanup.ksh \
 	functional/fallocate/fallocate_prealloc.ksh \
 	functional/fallocate/fallocate_punch-hole.ksh \
diff --git a/tests/zfs-tests/tests/functional/failmode/cleanup.ksh b/tests/zfs-tests/tests/functional/failmode/cleanup.ksh
new file mode 100755
index 000000000..59d225388
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/failmode/cleanup.ksh
@@ -0,0 +1,30 @@
+#!/bin/ksh -p
+# SPDX-License-Identifier: CDDL-1.0
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2025, Klara, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+default_cleanup
diff --git a/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_continue.ksh b/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_continue.ksh
new file mode 100755
index 000000000..f5f37b3f5
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_continue.ksh
@@ -0,0 +1,102 @@
+#!/bin/ksh -p
+# SPDX-License-Identifier: CDDL-1.0
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2025, Klara, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+log_assert "dmu_tx_assign() returns when pool suspends with failmode=continue"
+
+typeset -i dd_pid=0
+
+function cleanup
+{
+	zinject -c all || true
+	zpool clear $TESTPOOL || true
+	test $dd_pid -gt 0 && kill -9 $dd_pid || true
+	destroy_pool $TESTPOOL
+}
+
+log_onexit cleanup
+
+DISK=${DISKS%% *}
+
+# create a single-disk pool, set failmode=continue
+log_must zpool create -o failmode=continue -f $TESTPOOL $DISK
+log_must zfs create -o recordsize=128k $TESTPOOL/$TESTFS
+
+# start writing to a file in the background. these args to dd will make it
+# keep writing until it fills the pool, but we abort before that happens
+dd if=/dev/urandom of=/$TESTPOOL/$TESTFS/file bs=128k &
+dd_pid=$!
+
+# give it a moment for the write throttle to start pushing back
+sleep 2
+
+# force the pool to suspend by inducing the writes and followup probe to fail
+log_must zinject -d $DISK -e io -T write $TESTPOOL
+log_must zinject -d $DISK -e nxio -T probe $TESTPOOL
+
+# should only take a moment, but give it a chance
+log_note "waiting for pool to suspend"
+typeset -i tries=10
+until [[ $(kstat_pool $TESTPOOL state) == "SUSPENDED" ]] ; do
+	if ((tries-- == 0)); then
+		log_fail "pool didn't suspend"
+	fi
+	sleep 1
+done
+
+# dmu_tx_try_assign() should have noticed the suspend by now
+typeset -i suspended=$(kstat dmu_tx.dmu_tx_suspended)
+
+# dd should have exited with failure
+typeset -i blocked
+if kill -0 $dd_pid ; then
+	blocked=1
+	log_note "dd is blocked in the kernel!"
+else
+	blocked=0
+	log_note "dd exited while pool suspended"
+fi
+
+# bring the pool back online
+log_must zinject -c all
+log_must zpool clear $TESTPOOL
+
+# kill dd if it's still running, then get its return code
+# (it will be a failure if it was still running and we kill it, but we don't
+# care about that, because we already know it blocked)
+test $blocked -eq 1 && kill -9 $dd_pid
+wait $dd_pid
+typeset -i rc=$?
+dd_pid=0
+
+# confirm that dd failed when the pool suspended
+log_must test $suspended -ne 0
+log_must test $blocked -eq 0
+log_must test $rc -ne 0
+
+log_pass "dmu_tx_assign() returns when pool suspends with failmode=continue"
diff --git a/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_wait.ksh b/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_wait.ksh
new file mode 100755
index 000000000..882849426
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/failmode/failmode_dmu_tx_wait.ksh
@@ -0,0 +1,98 @@
+#!/bin/ksh -p
+# SPDX-License-Identifier: CDDL-1.0
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2025, Klara, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib
+
+log_assert "dmu_tx_assign() blocks when pool suspends with failmode=wait"
+
+typeset -i dd_pid=0
+
+function cleanup
+{
+	zinject -c all || true
+	zpool clear $TESTPOOL || true
+	test $dd_pid -gt 0 && kill -9 $dd_pid || true
+	destroy_pool $TESTPOOL
+}
+
+log_onexit cleanup
+
+DISK=${DISKS%% *}
+
+# create a single-disk pool, set failmode=wait
+log_must zpool create -o failmode=wait -f $TESTPOOL $DISK
+log_must zfs create -o recordsize=128k $TESTPOOL/$TESTFS
+
+# start writing to a file in the background. these args to dd will make it
+# keep writing until it fills the pool, but we will kill it before that happens.
+dd if=/dev/urandom of=/$TESTPOOL/$TESTFS/file bs=128k &
+dd_pid=$!
+
+# give it a moment for the write throttle to start pushing back
+sleep 2
+
+# force the pool to suspend by inducing the writes and followup probe to fail
+log_must zinject -d $DISK -e io -T write $TESTPOOL
+log_must zinject -d $DISK -e nxio -T probe $TESTPOOL
+
+# should only take a moment, but give it a chance
+log_note "waiting for pool to suspend"
+typeset -i tries=10
+until [[ $(kstat_pool $TESTPOOL state) == "SUSPENDED" ]] ; do
+	if ((tries-- == 0)); then
+		log_fail "pool didn't suspend"
+	fi
+	sleep 1
+done
+
+# dmu_tx_try_assign() should have noticed the suspend by now
+typeset -i suspended=$(kstat dmu_tx.dmu_tx_suspended)
+
+# dd should still be running, blocked in the kernel
+typeset -i blocked
+if kill -0 $dd_pid ; then
+	blocked=1
+	log_note "dd is blocked as expected"
+else
+	blocked=0
+	log_note "dd exited while pool suspended!"
+fi
+
+# bring the pool back online
+log_must zinject -c all
+log_must zpool clear $TESTPOOL
+
+# kill dd, we're done with it
+kill -9 $dd_pid
+wait $dd_pid
+dd_pid=0
+
+# confirm that dd was blocked in dmu_tx assign/wait
+log_must test $suspended -ne 0
+log_must test $blocked -eq 1
+
+log_pass "dmu_tx_assign() blocks when pool suspends with failmode=wait"
diff --git a/tests/zfs-tests/tests/functional/failmode/setup.ksh b/tests/zfs-tests/tests/functional/failmode/setup.ksh
new file mode 100755
index 000000000..099c6306d
--- /dev/null
+++ b/tests/zfs-tests/tests/functional/failmode/setup.ksh
@@ -0,0 +1,28 @@
+#!/bin/ksh -p
+# SPDX-License-Identifier: CDDL-1.0
+#
+# CDDL HEADER START
+#
+# The contents of this file are subject to the terms of the
+# Common Development and Distribution License (the "License").
+# You may not use this file except in compliance with the License.
+#
+# You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+# or https://opensource.org/licenses/CDDL-1.0.
+# See the License for the specific language governing permissions
+# and limitations under the License.
+#
+# When distributing Covered Code, include this CDDL HEADER in each
+# file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+# If applicable, add the following below this CDDL HEADER, with the
+# fields enclosed by brackets "[]" replaced with your own identifying
+# information: Portions Copyright [yyyy] [name of copyright owner]
+#
+# CDDL HEADER END
+#
+
+#
+# Copyright (c) 2025, Klara, Inc.
+#
+
+. $STF_SUITE/include/libtest.shlib