From: Wei Liu <wei.liu@kernel.org>
To: Sahil Chandna <sahilchandna@linux.microsoft.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com,
namjain@linux.microsoft.com, mhklinux@outlook.com,
hamzamahfooz@linux.microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, longli@microsoft.com, lpieralisi@kernel.org,
kwilczynski@kernel.org, mani@kernel.org, robh@kernel.org,
bhelgaas@google.com, linux-hyperv@vger.kernel.org,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4] PCI: hv: Warn when wait_for_response() waits indefinitely
Date: Mon, 21 Sep 2026 08:50:08 -0700 [thread overview]
Message-ID: <20260921155008.GA1566687@liuwe-devbox-debian-v2.local> (raw)
In-Reply-To: <20260914103918.3125157-1-sahilchandna@linux.microsoft.com>
On Mon, Sep 14, 2026 at 03:39:09AM -0700, Sahil Chandna wrote:
> A guest can wait indefinitely in wait_for_response() for the host to
> send either a rescind message or a packet completion. If the
> host does not send either, the guest can remain blocked with no
> diagnostic indicating a reason.
> This was observed during a guest kernel upgrade in which the
> host-side application handling the PCI channel faulted, causing the
> guest to never receive the completion request.
> Add a warning in wait_for_response() when the wait exceeds
> a timeout so that such a hang is visible in the guest's kernel log
> and can be correlated with host-side state.
>
> Suggested-by: Michael Kelley <mhklinux@outlook.com>
> Reviewed-by: Naman Jain <namjain@linux.microsoft.com>
> Signed-off-by: Sahil Chandna <sahilchandna@linux.microsoft.com>
Applied. Thanks.
prev parent reply other threads:[~2026-09-21 15:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-14 10:39 Sahil Chandna
2026-09-21 15:50 ` Wei Liu [this message]
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