linux-kernel - Re: [PATCH v2 1/1] Drivers: hv: Always do Hyper-V panic notification in hv_kmsg

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Message-ID: <20260115070150.GB3557088@liuwe-devbox-debian-v2.local>
Date: Thu, 15 Jan 2026 07:01:50 +0000
From: Wei Liu <wei.liu@...nel.org>
To: mhklinux@...look.com
Cc: haiyangz@...rosoft.com, wei.liu@...nel.org, decui@...rosoft.com,
	kys@...rosoft.com, linux-kernel@...r.kernel.org,
	linux-hyperv@...r.kernel.org, dan.carpenter@...aro.org
Subject: Re: [PATCH v2 1/1] Drivers: hv: Always do Hyper-V panic notification
 in hv_kmsg_dump()

On Wed, Dec 31, 2025 at 12:14:47PM -0800, mhkelley58@...il.com wrote:
> From: Michael Kelley <mhklinux@...look.com>
> 
> hv_kmsg_dump() currently skips the panic notification entirely if it
> doesn't get any message bytes to pass to Hyper-V due to an error from
> kmsg_dump_get_buffer(). Skipping the notification is undesirable because
> it leaves the Hyper-V host uncertain about the state of a panic'ed guest.
> 
> Fix this by always doing the panic notification, even if bytes_written
> is zero. Also ensure that bytes_written is initialized, which fixes a
> kernel test robot warning. The warning is actually bogus because
> kmsg_dump_get_buffer() happens to set bytes_written even if it fails, and
> in the kernel test robot's CONFIG_PRINTK not set case, hv_kmsg_dump() is
> never called. But do the initialization for robustness and to quiet the
> static checker.
> 
> Fixes: 9c318a1d9b50 ("Drivers: hv: move panic report code from vmbus to hv early init code")
> Reported-by: kernel test robot <lkp@...el.com>
> Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
> Closes: https://lore.kernel.org/all/202512172103.OcUspn1Z-lkp@intel.com/
> Signed-off-by: Michael Kelley <mhklinux@...look.com>

Applied. Thanks.