rcutorture: Fix rcu_torture_fwd_cb_cr() data race

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[ Upstream commit 6040072f47 ]

On powerpc systems, spinlock acquisition does not order prior stores
against later loads.  This means that this statement:

	rfcp->rfc_next = NULL;

Can be reordered to follow this statement:

	WRITE_ONCE(*rfcpp, rfcp);

Which is then a data race with rcu_torture_fwd_prog_cr(), specifically,
this statement:

	rfcpn = READ_ONCE(rfcp->rfc_next)

KCSAN located this data race, which represents a real failure on powerpc.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Marco Elver <elver@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: <kasan-dev@googlegroups.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

...

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Paul E. McKenney 2024-04-05 12:02:11 -07:00 • committed by Greg Kroah-Hartman

parent 95cf80c934

commit 7adbf9b5c8

1 changed files with 1 additions and 1 deletions

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kernel/rcu/rcutorture.c

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