diff --git a/fast-import.c b/fast-import.c
index 429ab491bd..71b89e2036 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -338,6 +338,98 @@ static int unread_command_buf;
 static uintmax_t next_mark;
 static struct dbuf new_data;
 
+static void write_branch_report(FILE *rpt, struct branch *b)
+{
+	fprintf(rpt, "%s:\n", b->name);
+
+	fprintf(rpt, "  status      :");
+	if (b->active)
+		fputs(" active", rpt);
+	if (b->branch_tree.tree)
+		fputs(" loaded", rpt);
+	if (is_null_sha1(b->branch_tree.versions[1].sha1))
+		fputs(" dirty", rpt);
+	fputc('\n', rpt);
+
+	fprintf(rpt, "  tip commit  : %s\n", sha1_to_hex(b->sha1));
+	fprintf(rpt, "  old tree    : %s\n", sha1_to_hex(b->branch_tree.versions[0].sha1));
+	fprintf(rpt, "  cur tree    : %s\n", sha1_to_hex(b->branch_tree.versions[1].sha1));
+	fprintf(rpt, "  commit clock: %" PRIuMAX "\n", b->last_commit);
+
+	fputs("  last pack   : ", rpt);
+	if (b->pack_id < MAX_PACK_ID)
+		fprintf(rpt, "%u", b->pack_id);
+	fputc('\n', rpt);
+
+	fputc('\n', rpt);
+}
+
+static void write_crash_report(const char *err, va_list params)
+{
+	char *loc = git_path("fast_import_crash_%d", getpid());
+	FILE *rpt = fopen(loc, "w");
+	struct branch *b;
+	unsigned long lu;
+
+	if (!rpt) {
+		error("can't write crash report %s: %s", loc, strerror(errno));
+		return;
+	}
+
+	fprintf(stderr, "fast-import: dumping crash report to %s\n", loc);
+
+	fprintf(rpt, "fast-import crash report:\n");
+	fprintf(rpt, "    fast-import process: %d\n", getpid());
+	fprintf(rpt, "    parent process     : %d\n", getppid());
+	fprintf(rpt, "    at %s\n", show_date(time(NULL), 0, DATE_LOCAL));
+	fputc('\n', rpt);
+
+	fputs("fatal: ", rpt);
+	vfprintf(rpt, err, params);
+	fputc('\n', rpt);
+
+	fputc('\n', rpt);
+	fputs("Active Branch LRU\n", rpt);
+	fputs("-----------------\n", rpt);
+	fprintf(rpt, "    active_branches = %lu cur, %lu max\n",
+		cur_active_branches,
+		max_active_branches);
+	fputc('\n', rpt);
+	fputs("  pos  clock name\n", rpt);
+	fputs("  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n", rpt);
+	for (b = active_branches, lu = 0; b; b = b->active_next_branch)
+		fprintf(rpt, "  %2lu) %6" PRIuMAX" %s\n",
+			++lu, b->last_commit, b->name);
+
+	fputc('\n', rpt);
+	fputs("Inactive Branches\n", rpt);
+	fputs("-----------------\n", rpt);
+	for (lu = 0; lu < branch_table_sz; lu++) {
+		for (b = branch_table[lu]; b; b = b->table_next_branch)
+			write_branch_report(rpt, b);
+	}
+
+	fputc('\n', rpt);
+	fputs("-------------------\n", rpt);
+	fputs("END OF CRASH REPORT\n", rpt);
+	fclose(rpt);
+}
+
+static NORETURN void die_nicely(const char *err, va_list params)
+{
+	static int zombie;
+
+	fputs("fatal: ", stderr);
+	vfprintf(stderr, err, params);
+	fputc('\n', stderr);
+
+	if (!zombie) {
+		zombie = 1;
+		write_crash_report(err, params);
+	}
+
+	exit(128);
+}
 
 static void alloc_objects(unsigned int cnt)
 {
@@ -2233,6 +2325,7 @@ int main(int argc, const char **argv)
 
 	prepare_packed_git();
 	start_packfile();
+	set_die_routine(die_nicely);
 	for (;;) {
 		read_next_command();
 		if (command_buf.eof)