ZTS: New test for kernel panic induced by redacted send

This change adds a new test that covers a bug fix in the binary search
in the redacted send resume logic that causes a kernel panic.
The bug was fixed in openzfs#11297.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Co-authored-by: John Kennedy <john.kennedy@delphix.com>
Signed-off-by: Palash Gandhi <palash.gandhi@delphix.com>
Closes openzfs#11764

tests/runfiles/common.run

@@ -722,8 +722,8 @@ tests = ['redacted_compressed', 'redacted_contents', 'redacted_deleted',
     'redacted_disabled_feature', 'redacted_embedded', 'redacted_holes',
     'redacted_incrementals', 'redacted_largeblocks', 'redacted_many_clones',
     'redacted_mixed_recsize', 'redacted_mounts', 'redacted_negative',
-    'redacted_origin', 'redacted_props', 'redacted_resume', 'redacted_size',
-    'redacted_volume']
+    'redacted_origin', 'redacted_panic', 'redacted_props', 'redacted_resume',
+    'redacted_size', 'redacted_volume']
 tags = ['functional', 'redacted_send']
 
 [tests/functional/raidz]

tests/zfs-tests/tests/functional/redacted_send/Makefile.am

@@ -15,6 +15,7 @@ dist_pkgdata_SCRIPTS = \
 	redacted_mounts.ksh \
 	redacted_negative.ksh \
 	redacted_origin.ksh \
+	redacted_panic.ksh \
 	redacted_props.ksh \
 	redacted_resume.ksh \
 	redacted_size.ksh \

tests/zfs-tests/tests/functional/redacted_send/redacted_panic.ksh

@@ -0,0 +1,44 @@
+#!/bin/ksh
+
+#
+# This file and its contents are supplied under the terms of the
+# Common Development and Distribution License ("CDDL"), version 1.0.
+# You may only use this file in accordance with the terms of version
+# 1.0 of the CDDL.
+#
+# A full copy of the text of the CDDL should have accompanied this
+# source.  A copy of the CDDL is also available via the Internet at
+# http://www.illumos.org/license/CDDL.
+#
+
+#
+# Copyright (c) 2021 by Delphix. All rights reserved.
+#
+
+. $STF_SUITE/tests/functional/redacted_send/redacted.kshlib
+
+#
+# Description:
+# Verify edge case when midbufid is equal to minbufid for the bug fixed by
+# https://github.com/openzfs/zfs/pull/11297 (Fix kernel panic induced by
+# redacted send)
+#
+
+typeset ds_name="panic"
+typeset sendfs="$POOL/$ds_name"
+typeset recvfs="$POOL2/$ds_name"
+typeset clone="$POOL/${ds_name}_clone"
+typeset stream=$(mktemp $tmpdir/stream.XXXX)
+
+log_onexit redacted_cleanup $sendfs $recvfs
+
+log_must zfs create -o recsize=8k $sendfs
+log_must dd if=/dev/urandom of=/$sendfs/file bs=1024k count=2048
+log_must zfs snapshot $sendfs@init
+log_must zfs clone $sendfs@init $clone
+log_must stride_dd -i /dev/urandom -o /$clone/file -b 8192 -s 2 -c 7226
+log_must zfs snapshot $clone@init
+log_must zfs redact $sendfs@init book_init $clone@init
+log_must eval "zfs send --redact $sendfs#book_init $sendfs@init >$stream"
+log_must eval "zfs recv $recvfs <$stream"
+log_pass