This is a note to let you know that I've just added the patch titled
idr test suite: Take RCU read lock in idr_find_test_1
to the 5.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
idr-test-suite-take-rcu-read-lock-in-idr_find_test_1.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5a7b6a49c97957f725be6865a6c092a8aed79762
Author: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Date: Thu Apr 1 07:44:48 2021 -0400
idr test suite: Take RCU read lock in idr_find_test_1
[ Upstream commit 703586410da69eb40062e64d413ca33bd735917a ]
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@xxxxxxxxxx>
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/testing/radix-tree/idr-test.c b/tools/testing/radix-tree/idr-test.c
index 44ceff95a9b3..4a9b451b7ba0 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);
