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Date:   Tue, 31 Aug 2021 13:16:07 +0000
From:   Wei Liu <wei.liu@kernel.org>
To:     longli@linuxonhyperv.com
Cc:     linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-hyperv@vger.kernel.org, Long Li <longli@microsoft.com>,
        "K. Y. Srinivasan" <kys@microsoft.com>,
        Haiyang Zhang <haiyangz@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Rob Herring <robh@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Michael Kelley <mikelley@microsoft.com>
Subject: Re: [Patch v2] PCI: hv: Fix sleep while in non-sleep context when
 removing child devices from the bus
Message-ID: <20210831131607.vsjvmr43eei4dsie@liuwe-devbox-debian-v2>
References: <1630365207-20616-1-git-send-email-longli@linuxonhyperv.com>
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On Mon, Aug 30, 2021 at 04:13:27PM -0700, longli@linuxonhyperv.com wrote:
> From: Long Li <longli@microsoft.com>
> 
> In hv_pci_bus_exit, the code is holding a spinlock while calling
> pci_destroy_slot(), which takes a mutex.
> 
> This is not safe for spinlock. Fix this by moving the children to be
> deleted to a list on the stack, and removing them after spinlock is
> released.
> 
> Fixes: 94d22763207a ("PCI: hv: Fix a race condition when removing the device")
> 
> Cc: "K. Y. Srinivasan" <kys@microsoft.com>
> Cc: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: Stephen Hemminger <sthemmin@microsoft.com>
> Cc: Wei Liu <wei.liu@kernel.org>
> Cc: Dexuan Cui <decui@microsoft.com>
> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> Cc: Rob Herring <robh@kernel.org>
> Cc: "Krzysztof Wilczyński" <kw@linux.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Michael Kelley <mikelley@microsoft.com>
> Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
> Link: https://lore.kernel.org/linux-hyperv/20210823152130.GA21501@kili/
> Signed-off-by: Long Li <longli@microsoft.com>

Reviewed-by: Wei Liu <wei.liu@kernel.org>