[PATCH V5 6/9] firmware: imx: scu-irq: fix RCU complains after M4 partition reset

Peng Fan (OSS)
2023-07-31T09:01:47Z

From: Robin Gong <yibin.gong@nxp.com>

Use blocking_notifier_chain instead of atomic_notifier_chain, otherwise
below RCU complains would come out since unregister/register_virtio_device
() will issue mbox message (mbox_send_message() is blocking) again after
received M4 partition reset. Actually, no need atomic for notifier which
is so tough for user since this notifier is called in worker instead of
interrupt handler directly.

[ 389.706645] i2c-rpmsg virtio0.rpmsg-i2c-channel.-1.2: i2c rpmsg driver is removed
[ 389.767362] Wait for remote ready timeout, use first_notify.
[ 389.774084] ------------[ cut here ]------------
[ 389.778729] WARNING: CPU: 0 PID: 397 at kernel/rcu/tree_plugin.h:293 rcu_note_context_switch+0x34/0x338
[ 389.788131] Modules linked in:
[ 389.791195] CPU: 0 PID: 397 Comm: kworker/0:13 Not tainted 5.4.0-rc5-02977-g08f78722f07b #26
[ 389.799633] Hardware name: Freescale i.MX8DXL Phantom MEK (DT)
[ 389.805481] Workqueue: events imx_scu_irq_work_handler

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
drivers/firmware/imx/imx-scu-irq.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/firmware/imx/imx-scu-irq.c b/drivers/firmware/imx/imx-scu-irq.c
index d9dcc20945c6..4408f150b3d5 100644
--- a/drivers/firmware/imx/imx-scu-irq.c
+++ b/drivers/firmware/imx/imx-scu-irq.c
@@ -42,25 +42,25 @@ struct imx_sc_msg_irq_enable {

static struct imx_sc_ipc *imx_sc_irq_ipc_handle;
static struct work_struct imx_sc_irq_work;
-static ATOMIC_NOTIFIER_HEAD(imx_scu_irq_notifier_chain);
+static BLOCKING_NOTIFIER_HEAD(imx_scu_irq_notifier_chain);

int imx_scu_irq_register_notifier(struct notifier_block *nb)
{
- return atomic_notifier_chain_register(
+ return blocking_notifier_chain_register(
&imx_scu_irq_notifier_chain, nb);
}
EXPORT_SYMBOL(imx_scu_irq_register_notifier);

int imx_scu_irq_unregister_notifier(struct notifier_block *nb)
{
- return atomic_notifier_chain_unregister(
+ return blocking_notifier_chain_unregister(
&imx_scu_irq_notifier_chain, nb);
}
EXPORT_SYMBOL(imx_scu_irq_unregister_notifier);

static int imx_scu_irq_notifier_call_chain(unsigned long status, u8 *group)
{
- return atomic_notifier_call_chain(&imx_scu_irq_notifier_chain,
+ return blocking_notifier_call_chain(&imx_scu_irq_notifier_chain,
status, (void *)group);
}

--
2.37.1