On Fri, Feb 25, 2022 at 05:53:16PM +0000, Biju Das wrote:
> This patch fixes the issue 'BUG: Invalid wait context' during restart()
> callback by using clk_prepare_enable() instead of pm_runtime_get_sync()
> for turning on the clocks during restart.
>
> This issue is noticed when testing with renesas_defconfig.
>
> [ 42.213802] reboot: Restarting system
> [ 42.217860]
> [ 42.219364] =============================
> [ 42.223368] [ BUG: Invalid wait context ]
> [ 42.227372] 5.17.0-rc5-arm64-renesas-00002-g10393723e35e #522 Not tainted
> [ 42.234153] -----------------------------
> [ 42.238155] systemd-shutdow/1 is trying to lock:
> [ 42.242766] ffff00000a650828 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x14/0x20
> [ 42.250709] other info that might help us debug this:
> [ 42.255753] context-{4:4}
> [ 42.258368] 2 locks held by systemd-shutdow/1:
> [ 42.262806] #0: ffff80000944e1c8 (system_transition_mutex#2){+.+.}-{3:3}, at: __do_sys_reboot+0xd0/0x250
> [ 42.272388] #1: ffff8000094c4e40 (rcu_read_lock){....}-{1:2}, at: atomic_notifier_call_chain+0x0/0x150
> [ 42.281795] stack backtrace:
> [ 42.284672] CPU: 0 PID: 1 Comm: systemd-shutdow Not tainted 5.17.0-rc5-arm64-renesas-00002-g10393723e35e #522
> [ 42.294577] Hardware name: Renesas SMARC EVK based on r9a07g044c2 (DT)
> [ 42.301096] Call trace:
> [ 42.303538] dump_backtrace+0xcc/0xd8
> [ 42.307203] show_stack+0x14/0x30
> [ 42.310517] dump_stack_lvl+0x88/0xb0
> [ 42.314180] dump_stack+0x14/0x2c
> [ 42.317492] __lock_acquire+0x1b24/0x1b50
> [ 42.321502] lock_acquire+0x120/0x3a8
> [ 42.325162] __mutex_lock+0x84/0x8f8
> [ 42.328737] mutex_lock_nested+0x30/0x58
> [ 42.332658] genpd_lock_mtx+0x14/0x20
> [ 42.336319] genpd_runtime_resume+0xc4/0x228
> [ 42.340587] __rpm_callback+0x44/0x170
> [ 42.344337] rpm_callback+0x64/0x70
> [ 42.347824] rpm_resume+0x4e0/0x6b8
> [ 42.351310] __pm_runtime_resume+0x50/0x78
> [ 42.355404] rzg2l_wdt_restart+0x28/0x68
> [ 42.359329] watchdog_restart_notifier+0x1c/0x30
> [ 42.363943] atomic_notifier_call_chain+0x94/0x150
> [ 42.368732] do_kernel_restart+0x24/0x30
> [ 42.372652] machine_restart+0x44/0x70
> [ 42.376399] kernel_restart+0x3c/0x60
> [ 42.380058] __do_sys_reboot+0x228/0x250
> [ 42.383977] __arm64_sys_reboot+0x20/0x28
> [ 42.387983] invoke_syscall+0x40/0xf8
>
> Fixes: 2cbc5cd0b55fa2 ("watchdog: Add Watchdog Timer driver for RZ/G2L")
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> ---
> V4->V5:
> * Added Rb tag from Geert.
> * CC'ed Linux PM.
> V4:
> * New patch
> ---
> drivers/watchdog/rzg2l_wdt.c | 25 +++++++++++++------------
> 1 file changed, 13 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/watchdog/rzg2l_wdt.c b/drivers/watchdog/rzg2l_wdt.c
> index 0fc73b8a9567..48dfe6e5e64f 100644
> --- a/drivers/watchdog/rzg2l_wdt.c
> +++ b/drivers/watchdog/rzg2l_wdt.c
> @@ -43,6 +43,8 @@ struct rzg2l_wdt_priv {
> struct reset_control *rstc;
> unsigned long osc_clk_rate;
> unsigned long delay;
> + struct clk *pclk;
> + struct clk *osc_clk;
> };
>
> static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv)
> @@ -118,7 +120,9 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
>
> /* Reset the module before we modify any register */
> reset_control_reset(priv->rstc);
> - pm_runtime_get_sync(wdev->parent);
> +
> + clk_prepare_enable(priv->pclk);
> + clk_prepare_enable(priv->osc_clk);
>
> /* smallest counter value to reboot soon */
> rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(1), WDTSET);
> @@ -165,7 +169,6 @@ static int rzg2l_wdt_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct rzg2l_wdt_priv *priv;
> unsigned long pclk_rate;
> - struct clk *wdt_clk;
> int ret;
>
> priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> @@ -177,22 +180,20 @@ static int rzg2l_wdt_probe(struct platform_device *pdev)
> return PTR_ERR(priv->base);
>
> /* Get watchdog main clock */
> - wdt_clk = clk_get(&pdev->dev, "oscclk");
> - if (IS_ERR(wdt_clk))
> - return dev_err_probe(&pdev->dev, PTR_ERR(wdt_clk), "no oscclk");
> + priv->osc_clk = devm_clk_get(&pdev->dev, "oscclk");
> + if (IS_ERR(priv->osc_clk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(priv->osc_clk), "no oscclk");
>
> - priv->osc_clk_rate = clk_get_rate(wdt_clk);
> - clk_put(wdt_clk);
> + priv->osc_clk_rate = clk_get_rate(priv->osc_clk);
> if (!priv->osc_clk_rate)
> return dev_err_probe(&pdev->dev, -EINVAL, "oscclk rate is 0");
>
> /* Get Peripheral clock */
> - wdt_clk = clk_get(&pdev->dev, "pclk");
> - if (IS_ERR(wdt_clk))
> - return dev_err_probe(&pdev->dev, PTR_ERR(wdt_clk), "no pclk");
> + priv->pclk = devm_clk_get(&pdev->dev, "pclk");
> + if (IS_ERR(priv->pclk))
> + return dev_err_probe(&pdev->dev, PTR_ERR(priv->pclk), "no pclk");
>
> - pclk_rate = clk_get_rate(wdt_clk);
> - clk_put(wdt_clk);
> + pclk_rate = clk_get_rate(priv->pclk);
> if (!pclk_rate)
> return dev_err_probe(&pdev->dev, -EINVAL, "pclk rate is 0");
>
> --
> 2.17.1
>
