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Subject: Re: [PATCH] irqchip/mbigen: Set driver .suppress_bind_attrs to avoid
 remove problems
To:     John Garry <john.garry@huawei.com>, <tglx@linutronix.de>,
        <jason@lakedaemon.net>, <maz@kernel.org>
CC:     <linuxarm@huawei.com>, <linux-kernel@vger.kernel.org>
References: <1579196323-180137-1-git-send-email-john.garry@huawei.com>
From:   Hanjun Guo <guohanjun@huawei.com>
Message-ID: <1cd162d0-c66e-8107-fc09-f3cacb88f3a8@huawei.com>
Date:   Fri, 17 Jan 2020 09:21:58 +0800
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On 2020/1/17 1:38, John Garry wrote:
> The following crash can be seen for setting
> CONFIG_DEBUG_TEST_DRIVER_REMOVE=y for DT FW (which some people still use):
> 
> Hisilicon MBIGEN-V2 60080000.interrupt-controller: Failed to create mbi-gen irqdomain
> Hisilicon MBIGEN-V2: probe of 60080000.interrupt-controller failed with error -12
> 
> [...]
> 
> Unable to handle kernel paging request at virtual address 0000000000005008
>  Mem abort info:
>    ESR = 0x96000004
>    EC = 0x25: DABT (current EL), IL = 32 bits
>    SET = 0, FnV = 0
>    EA = 0, S1PTW = 0
>  Data abort info:
>    ISV = 0, ISS = 0x00000004
>    CM = 0, WnR = 0
>  user pgtable: 4k pages, 48-bit VAs, pgdp=0000041fb9990000
>  [0000000000005008] pgd=0000000000000000
>  Internal error: Oops: 96000004 [#1] PREEMPT SMP
>  Modules linked in:
>  CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.5.0-rc6-00002-g3fc42638a506-dirty #1622
>  Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT21 Nemo 2.0 RC0 04/18/2018
>  pstate: 40000085 (nZcv daIf -PAN -UAO)
>  pc : mbigen_set_type+0x38/0x60
>  lr : __irq_set_trigger+0x6c/0x188
>  sp : ffff800014b4b400
>  x29: ffff800014b4b400 x28: 0000000000000007
>  x27: 0000000000000000 x26: 0000000000000000
>  x25: ffff041fd83bd0d4 x24: ffff041fd83bd188
>  x23: 0000000000000000 x22: ffff80001193ce00
>  x21: 0000000000000004 x20: 0000000000000000
>  x19: ffff041fd83bd000 x18: ffffffffffffffff
>  x17: 0000000000000000 x16: 0000000000000000
>  x15: ffff8000119098c8 x14: ffff041fb94ec91c
>  x13: ffff041fb94ec1a1 x12: 0000000000000030
>  x11: 0101010101010101 x10: 0000000000000040
>  x9 : 0000000000000000 x8 : ffff041fb98c6680
>  x7 : ffff800014b4b380 x6 : ffff041fd81636c8
>  x5 : 0000000000000000 x4 : 000000000000025f
>  x3 : 0000000000005000 x2 : 0000000000005008
>  x1 : 0000000000000004 x0 : 0000000080000000
>  Call trace:
>   mbigen_set_type+0x38/0x60
>   __setup_irq+0x744/0x900
>   request_threaded_irq+0xe0/0x198
>   pcie_pme_probe+0x98/0x118
>   pcie_port_probe_service+0x38/0x78
>   really_probe+0xa0/0x3e0
>   driver_probe_device+0x58/0x100
>   __device_attach_driver+0x90/0xb0
>   bus_for_each_drv+0x64/0xc8
>   __device_attach+0xd8/0x138
>   device_initial_probe+0x10/0x18
>   bus_probe_device+0x90/0x98
>   device_add+0x4c4/0x770
>   device_register+0x1c/0x28
>   pcie_port_device_register+0x1e4/0x4f0
>   pcie_portdrv_probe+0x34/0xd8
>   local_pci_probe+0x3c/0xa0
>   pci_device_probe+0x128/0x1c0
>   really_probe+0xa0/0x3e0
>   driver_probe_device+0x58/0x100
>   __device_attach_driver+0x90/0xb0
>   bus_for_each_drv+0x64/0xc8
>   __device_attach+0xd8/0x138
>   device_attach+0x10/0x18
>   pci_bus_add_device+0x4c/0xb8
>   pci_bus_add_devices+0x38/0x88
>   pci_host_probe+0x3c/0xc0
>   pci_host_common_probe+0xf0/0x208
>   hisi_pcie_almost_ecam_probe+0x24/0x30
>   platform_drv_probe+0x50/0xa0
>   really_probe+0xa0/0x3e0
>   driver_probe_device+0x58/0x100
>   device_driver_attach+0x6c/0x90
>   __driver_attach+0x84/0xc8
>   bus_for_each_dev+0x74/0xc8
>   driver_attach+0x20/0x28
>   bus_add_driver+0x148/0x1f0
>   driver_register+0x60/0x110
>   __platform_driver_register+0x40/0x48
>   hisi_pcie_almost_ecam_driver_init+0x1c/0x24
> 
> The specific problem here is that the mbigen driver real probe has failed
> as the mbigen_of_create_domain()->of_platform_device_create() call fails,
> the reason for that being that we never destroyed the platform device
> created during the remove test dry run and there is some conflict.
> 
> Since we generally would never want to unbind this driver, and to save
> adding a driver tear down path for that, just set the driver
> .suppress_bind_attrs member to avoid this possibility.
> 
> Signed-off-by: John Garry <john.garry@huawei.com>
> 
> diff --git a/drivers/irqchip/irq-mbigen.c b/drivers/irqchip/irq-mbigen.c
> index 3f09f658e8e2..6b566bba263b 100644
> --- a/drivers/irqchip/irq-mbigen.c
> +++ b/drivers/irqchip/irq-mbigen.c
> @@ -374,6 +374,7 @@ static struct platform_driver mbigen_platform_driver = {
>  		.name		= "Hisilicon MBIGEN-V2",
>  		.of_match_table	= mbigen_of_match,
>  		.acpi_match_table = ACPI_PTR(mbigen_acpi_match),
> +		.suppress_bind_attrs = true,
>  	},
>  	.probe			= mbigen_device_probe,
>  };

Reviewed-by: Hanjun Guo <guohanjun@huawei.com>