diff --git a/repair/globals.c b/repair/globals.c
index 110d98b..537d068 100644
--- a/repair/globals.c
+++ b/repair/globals.c
@@ -117,3 +117,6 @@
 
 int		ag_stride;
 int		thread_count;
+
+/* If nonzero, simulate failure after this phase. */
+int		fail_after_phase;
diff --git a/repair/globals.h b/repair/globals.h
index 1d397b3..a928732 100644
--- a/repair/globals.h
+++ b/repair/globals.h
@@ -162,4 +162,7 @@
 extern int		ag_stride;
 extern int		thread_count;
 
+/* If nonzero, simulate failure after this phase. */
+extern int		fail_after_phase;
+
 #endif /* _XFS_REPAIR_GLOBAL_H */
diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
index a9236bb..64d7607 100644
--- a/repair/xfs_repair.c
+++ b/repair/xfs_repair.c
@@ -362,6 +362,10 @@
 
 	if (report_corrected && no_modify)
 		usage();
+
+	p = getenv("XFS_REPAIR_FAIL_AFTER_PHASE");
+	if (p)
+		fail_after_phase = (int)strtol(p, NULL, 0);
 }
 
 void __attribute__((noreturn))
@@ -853,6 +857,10 @@
 phase_end(int phase)
 {
 	timestamp(PHASE_END, phase, NULL);
+
+	/* Fail if someone injected an post-phase error. */
+	if (fail_after_phase && phase == fail_after_phase)
+		platform_crash();
 }
 
 int