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([111.202.175.140]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2c164f6cea3sm6261575ad.7.2026.06.02.19.12.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2026 19:12:06 -0700 (PDT) From: Gui-Dong Han To: scott.branden@broadcom.com, gregkh@linuxfoundation.org, arnd@arndb.de Cc: bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, Gui-Dong Han Subject: [PATCH] misc: bcm-vk: Use acquire/release for msgq_inited Date: Wed, 3 Jun 2026 10:11:27 +0800 Message-Id: <20260603021127.3285057-1-hanguidong02@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" bcm_vk_sync_msgq() fills the message queue information and then sets msgq_inited. Readers call bcm_vk_drv_access_ok() before accessing the message queues and their cached queue information. atomic_set()/atomic_read() do not order those accesses. A reader can see msgq_inited set while still seeing stale queue information. Use release when publishing the initialized queues and acquire when checking the gate. Keep the clear in bcm_vk_blk_drv_access() as atomic_set(). It closes the gate and does not publish queue state to readers. Fixes: 111d746bb476 ("misc: bcm-vk: add VK messaging support") Signed-off-by: Gui-Dong Han --- Found by auditing atomic operations used for synchronization. A similar fix can be found in 6df8e84aa6b5. --- drivers/misc/bcm-vk/bcm_vk_msg.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.c b/drivers/misc/bcm-vk/bcm_vk_= msg.c index 3916ec07ecad..2c084a6b3a92 100644 --- a/drivers/misc/bcm-vk/bcm_vk_msg.c +++ b/drivers/misc/bcm-vk/bcm_vk_msg.c @@ -108,7 +108,8 @@ u32 msgq_avail_space(const struct bcm_vk_msgq __iomem *= msgq, =20 bool bcm_vk_drv_access_ok(struct bcm_vk *vk) { - return (!!atomic_read(&vk->msgq_inited)); + /* Pair with the release store after message queue initialization. */ + return !!atomic_read_acquire(&vk->msgq_inited); } =20 void bcm_vk_set_host_alert(struct bcm_vk *vk, u32 bit_mask) @@ -501,7 +502,8 @@ int bcm_vk_sync_msgq(struct bcm_vk *vk, bool force_sync) msgq++; } } - atomic_set(&vk->msgq_inited, 1); + /* Publish message queue info before allowing driver access. */ + atomic_set_release(&vk->msgq_inited, 1); =20 return ret; } --=20 2.34.1