[PATCH 5.4 10/18] idr test suite: Create anchor before launching throbber - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 10/18] idr test suite: Create anchor before launching throbber
Date: Thu, 15 Apr 2021 16:48:03 +0200	[thread overview]
Message-ID: <20210415144413.374056584@linuxfoundation.org> (raw)
In-Reply-To: <20210415144413.055232956@linuxfoundation.org>

From: Matthew Wilcox (Oracle) <willy@infradead.org>

[ Upstream commit 094ffbd1d8eaa27ed426feb8530cb1456348b018 ]

The throbber could race with creation of the anchor entry and cause the
IDR to have zero entries in it, which would cause the test to fail.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/radix-tree/idr-test.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
index 4a9b451b7ba0..6ce7460f3c7a 100644
--- a/tools/testing/radix-tree/idr-test.c
+++ b/tools/testing/radix-tree/idr-test.c
@@ -301,11 +301,11 @@ void idr_find_test_1(int anchor_id, int throbber_id)
 	pthread_t throbber;
 	time_t start = time(NULL);
 
-	pthread_create(&throbber, NULL, idr_throbber, &throbber_id);
-
 	BUG_ON(idr_alloc(&find_idr, xa_mk_value(anchor_id), anchor_id,
 				anchor_id + 1, GFP_KERNEL) != anchor_id);
 
+	pthread_create(&throbber, NULL, idr_throbber, &throbber_id);
+
 	rcu_read_lock();
 	do {
 		int id = 0;
-- 
2.30.2



