From 703586410da69eb40062e64d413ca33bd735917a Mon Sep 17 00:00:00 2001
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: Thu, 1 Apr 2021 07:44:48 -0400
Subject: [PATCH] idr test suite: Take RCU read lock in idr_find_test_1
When run on a single CPU, this test would frequently access already-freed
memory. Due to timing, this bug never showed up on multi-CPU tests.
Reported-by: Chris von Recklinghausen <crecklin@redhat.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
tools/testing/radix-tree/idr-test.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
index 44ceff95a9b30..4a9b451b7ba03 100644
--- a/tools/testing/radix-tree/idr-test.c
+++ b/tools/testing/radix-tree/idr-test.c
@@ -306,11 +306,15 @@ void idr_find_test_1(int anchor_id, int throbber_id)
BUG_ON(idr_alloc(&find_idr, xa_mk_value(anchor_id), anchor_id,
anchor_id + 1, GFP_KERNEL) != anchor_id);
+ rcu_read_lock();
do {
int id = 0;
void *entry = idr_get_next(&find_idr, &id);
+ rcu_read_unlock();
BUG_ON(entry != xa_mk_value(id));
+ rcu_read_lock();
} while (time(NULL) < start + 11);
+ rcu_read_unlock();
pthread_join(throbber, NULL);
--
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