[PATCH v2 01/11] powerpc: qspinlock: Mark accesses to qnode lock checks
From: Rohan McLure <hidden>
Date: 2023-05-10 03:35:07
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
The powerpc implemenation of qspinlocks will both poll and spin on the bitlock guarding a qnode. Mark these accesses with READ_ONCE to convey to KCSAN that polling is intentional here. Signed-off-by: Rohan McLure <redacted> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> --- arch/powerpc/lib/qspinlock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/lib/qspinlock.c b/arch/powerpc/lib/qspinlock.c
index e4bd145255d0..b76c1f6acce5 100644
--- a/arch/powerpc/lib/qspinlock.c
+++ b/arch/powerpc/lib/qspinlock.c@@ -435,7 +435,7 @@ static __always_inline bool yield_to_prev(struct qspinlock *lock, struct qnode * smp_rmb(); /* See __yield_to_locked_owner comment */ - if (!node->locked) { + if (!READ_ONCE(node->locked)) { yield_to_preempted(prev_cpu, yield_count); spin_begin(); return preempted;
@@ -584,7 +584,7 @@ static __always_inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, b /* Wait for mcs node lock to be released */ spin_begin(); - while (!node->locked) { + while (!READ_ONCE(node->locked)) { spec_barrier(); if (yield_to_prev(lock, node, old, paravirt))
--
2.37.2