From: Tony Lindgren <tony@atomide.com>
To: Dave Gerlach <d-gerlach@ti.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org,
Suman Anna <s-anna@ti.com>
Subject: Re: [PATCH] soc: ti: wkup_m3_ipc: Fix race condition with rproc_boot
Date: Tue, 17 Dec 2019 10:25:34 -0800 [thread overview]
Message-ID: <20191217182534.GD35479@atomide.com> (raw)
In-Reply-To: <20191212040314.14753-1-d-gerlach@ti.com>
Hi,
* Dave Gerlach <d-gerlach@ti.com> [191211 20:02]:
> Any user of wkup_m3_ipc calls wkup_m3_ipc_get to get a handle and this
> checks the value of the static variable m3_ipc_state to see if the
> wkup_m3 is ready. Currently this is populated during probe before
> rproc_boot has been called, meaning there is a window of time that
> wkup_m3_ipc_get can return a valid handle but the wkup_m3 itself is not
> ready, leading to invalid IPC calls to the wkup_m3 and system
> instability.
>
> To avoid this, move the population of the m3_ipc_state variable until
> after rproc_boot has succeeded to guarantee a valid and usable handle
> is always returned.
Santosh, do you want me to pick this one into my fixes branch?
Regards,
Tony
> Reported-by: Suman Anna <s-anna@ti.com>
> Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
> ---
> drivers/soc/ti/wkup_m3_ipc.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/soc/ti/wkup_m3_ipc.c b/drivers/soc/ti/wkup_m3_ipc.c
> index 378369d9364a..e9ece45d7a33 100644
> --- a/drivers/soc/ti/wkup_m3_ipc.c
> +++ b/drivers/soc/ti/wkup_m3_ipc.c
> @@ -419,6 +419,8 @@ static void wkup_m3_rproc_boot_thread(struct wkup_m3_ipc *m3_ipc)
> ret = rproc_boot(m3_ipc->rproc);
> if (ret)
> dev_err(dev, "rproc_boot failed\n");
> + else
> + m3_ipc_state = m3_ipc;
>
> do_exit(0);
> }
> @@ -505,8 +507,6 @@ static int wkup_m3_ipc_probe(struct platform_device *pdev)
> goto err_put_rproc;
> }
>
> - m3_ipc_state = m3_ipc;
> -
> return 0;
>
> err_put_rproc:
> --
> 2.20.1
>
next prev parent reply other threads:[~2019-12-17 18:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-12 4:03 [PATCH] soc: ti: wkup_m3_ipc: Fix race condition with rproc_boot Dave Gerlach
2019-12-17 18:25 ` Tony Lindgren [this message]
2019-12-17 18:32 ` santosh.shilimkar
2019-12-17 18:35 ` Tony Lindgren
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