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Re: [PATCH] xen/privcmd: unregister xenstore notifier on module exit

To: GuoHan Zhao <zhaoguohan@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>

From: Jürgen Groß <jgross@xxxxxxxx>

Date: Wed, 25 Mar 2026 14:59:43 +0100

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Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx

Delivery-date: Wed, 25 Mar 2026 13:59:54 +0000

List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 25.03.26 13:02, GuoHan Zhao wrote:

Commit 453b8fb68f36 ("xen/privcmd: restrict usage in
unprivileged domU") added a xenstore notifier to defer setting the
restriction target until Xenstore is ready.

XEN_PRIVCMD can be built as a module, but privcmd_exit() leaves that
notifier behind. Balance the notifier lifecycle by unregistering it on
module exit.

This is harmless even if xenstore was already ready at registration
time and the notifier was never queued on the chain.

Fixes: 453b8fb68f3641fe ("xen/privcmd: restrict usage in unprivileged domU")
Signed-off-by: GuoHan Zhao <zhaoguohan@xxxxxxxxxx>

Thanks for catching this! Reviewed-by: Juergen Gross <jgross@xxxxxxxx> Juergen

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