Date: Mon, 23 Nov 2015 19:22:09 +0800
From: Jisheng Zhang <jszhang@marvell.com>
To: Sekhar Nori <nsekhar@ti.com>
CC: Murali Karicheri <m-karicheri2@ti.com>,
        Bjorn Helgaas <bhelgaas@google.com>, <linux-pci@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] PCI: keystone: fix crash with deferred probe
Message-ID: <20151123192209.38e2c101@xhacker>
In-Reply-To: <866b2f1544f9d55fa932aa9f9cb5e7d523a23d05.1448017883.git.nsekhar@ti.com>
References: <866b2f1544f9d55fa932aa9f9cb5e7d523a23d05.1448017883.git.nsekhar@ti.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Dear Sekhar,

On Fri, 20 Nov 2015 16:47:02 +0530
Sekhar Nori wrote:

> Drop __init annotations for functions called during
> probe of keystone PCIe host.
> 
> This fixes kernel crashes seen because of init data
> reclamation if the driver defer probes because of
> phy unavailability.
> 
> While at it, drop the useless __refdata annotation
> to driver structure. If its really needed, it should
> be added back with a comment explaining why.
> 
> Signed-off-by: Sekhar Nori <nsekhar@ti.com>
> ---
>  drivers/pci/host/pci-keystone-dw.c | 2 +-
>  drivers/pci/host/pci-keystone.c    | 6 +++---
>  2 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/pci/host/pci-keystone-dw.c b/drivers/pci/host/pci-keystone-dw.c
> index ed34c9520a02..47ddbcce53ca 100644
> --- a/drivers/pci/host/pci-keystone-dw.c
> +++ b/drivers/pci/host/pci-keystone-dw.c
> @@ -469,7 +469,7 @@ void ks_dw_pcie_initiate_link_train(struct keystone_pcie *ks_pcie)
>   * and call dw_pcie_v3_65_host_init() API to initialize the Keystone
>   * PCI host controller.
>   */
> -int __init ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
> +int ks_dw_pcie_host_init(struct keystone_pcie *ks_pcie,
>  				struct device_node *msi_intc_np)

when trying to add berlin pcie support and came up one patch

http://lists.infradead.org/pipermail/linux-arm-kernel/2015-November/384575.html

when build testing, I also realized this issue, but keystone relies on
hook_fault_code() which is will be freed after boot, so your patch isn't
completed.

And from the keystone driver implementation, it seems assume the driver won't
be defer probed.

Thanks

>  {
>  	struct pcie_port *pp = &ks_pcie->pp;
> diff --git a/drivers/pci/host/pci-keystone.c b/drivers/pci/host/pci-keystone.c
> index 0aa81bd3de12..593a58834c7d 100644
> --- a/drivers/pci/host/pci-keystone.c
> +++ b/drivers/pci/host/pci-keystone.c
> @@ -291,7 +291,7 @@ static struct pcie_host_ops keystone_pcie_host_ops = {
>  	.scan_bus = ks_dw_pcie_v3_65_scan_bus,
>  };
>  
> -static int __init ks_add_pcie_port(struct keystone_pcie *ks_pcie,
> +static int ks_add_pcie_port(struct keystone_pcie *ks_pcie,
>  			 struct platform_device *pdev)
>  {
>  	struct pcie_port *pp = &ks_pcie->pp;
> @@ -340,7 +340,7 @@ static int __exit ks_pcie_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -static int __init ks_pcie_probe(struct platform_device *pdev)
> +static int ks_pcie_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
>  	struct keystone_pcie *ks_pcie;
> @@ -396,7 +396,7 @@ fail_clk:
>  	return ret;
>  }
>  
> -static struct platform_driver ks_pcie_driver __refdata = {
> +static struct platform_driver ks_pcie_driver = {
>  	.probe  = ks_pcie_probe,
>  	.remove = __exit_p(ks_pcie_remove),
>  	.driver = {

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