* [PATCH 1/1] xen/manage: enable C_A_D to force reboot
@ 2020-05-13 23:34 ` Dongli Zhang
0 siblings, 0 replies; 6+ messages in thread
From: Dongli Zhang @ 2020-05-13 23:34 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: boris.ostrovsky, jgross, sstabellini, joe.jin, rose.wang
The systemd may be configured to mask ctrl-alt-del via "systemctl mask
ctrl-alt-del.target". As a result, the pv reboot would not work as signal
is ignored.
This patch always enables C_A_D before the call of ctrl_alt_del() in order
to force the reboot.
Reported-by: Rose Wang <rose.wang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
drivers/xen/manage.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index cd046684e0d1..3190d0ecb52e 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -204,6 +204,13 @@ static void do_poweroff(void)
static void do_reboot(void)
{
shutting_down = SHUTDOWN_POWEROFF; /* ? */
+ /*
+ * The systemd may be configured to mask ctrl-alt-del via
+ * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
+ * would not work. To enable C_A_D would force the reboot.
+ */
+ C_A_D = 1;
+
ctrl_alt_del();
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 1/1] xen/manage: enable C_A_D to force reboot
@ 2020-05-13 23:34 ` Dongli Zhang
0 siblings, 0 replies; 6+ messages in thread
From: Dongli Zhang @ 2020-05-13 23:34 UTC (permalink / raw)
To: xen-devel, linux-kernel
Cc: jgross, rose.wang, boris.ostrovsky, sstabellini, joe.jin
The systemd may be configured to mask ctrl-alt-del via "systemctl mask
ctrl-alt-del.target". As a result, the pv reboot would not work as signal
is ignored.
This patch always enables C_A_D before the call of ctrl_alt_del() in order
to force the reboot.
Reported-by: Rose Wang <rose.wang@oracle.com>
Cc: Joe Jin <joe.jin@oracle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
---
drivers/xen/manage.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
index cd046684e0d1..3190d0ecb52e 100644
--- a/drivers/xen/manage.c
+++ b/drivers/xen/manage.c
@@ -204,6 +204,13 @@ static void do_poweroff(void)
static void do_reboot(void)
{
shutting_down = SHUTDOWN_POWEROFF; /* ? */
+ /*
+ * The systemd may be configured to mask ctrl-alt-del via
+ * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
+ * would not work. To enable C_A_D would force the reboot.
+ */
+ C_A_D = 1;
+
ctrl_alt_del();
}
--
2.17.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] xen/manage: enable C_A_D to force reboot
2020-05-13 23:34 ` Dongli Zhang
@ 2020-05-15 7:01 ` Jürgen Groß
-1 siblings, 0 replies; 6+ messages in thread
From: Jürgen Groß @ 2020-05-15 7:01 UTC (permalink / raw)
To: Dongli Zhang, xen-devel, linux-kernel
Cc: boris.ostrovsky, sstabellini, joe.jin, rose.wang
On 14.05.20 01:34, Dongli Zhang wrote:
> The systemd may be configured to mask ctrl-alt-del via "systemctl mask
> ctrl-alt-del.target". As a result, the pv reboot would not work as signal
> is ignored.
>
> This patch always enables C_A_D before the call of ctrl_alt_del() in order
> to force the reboot.
Hmm, I'm not sure this is a good idea.
Suppose a guest admin is doing a critical update and wants to avoid a
sudden reboot in between. By masking the reboot this would be possible,
with your patch it isn't.
In case a reboot is really mandatory it would still be possible to just
kill the guest.
I'm not completely opposed to the patch, but I think this is a change
which should not be done easily.
Juergen
>
> Reported-by: Rose Wang <rose.wang@oracle.com>
> Cc: Joe Jin <joe.jin@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
> drivers/xen/manage.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index cd046684e0d1..3190d0ecb52e 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -204,6 +204,13 @@ static void do_poweroff(void)
> static void do_reboot(void)
> {
> shutting_down = SHUTDOWN_POWEROFF; /* ? */
> + /*
> + * The systemd may be configured to mask ctrl-alt-del via
> + * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
> + * would not work. To enable C_A_D would force the reboot.
> + */
> + C_A_D = 1;
> +
> ctrl_alt_del();
> }
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] xen/manage: enable C_A_D to force reboot
@ 2020-05-15 7:01 ` Jürgen Groß
0 siblings, 0 replies; 6+ messages in thread
From: Jürgen Groß @ 2020-05-15 7:01 UTC (permalink / raw)
To: Dongli Zhang, xen-devel, linux-kernel
Cc: rose.wang, boris.ostrovsky, sstabellini, joe.jin
On 14.05.20 01:34, Dongli Zhang wrote:
> The systemd may be configured to mask ctrl-alt-del via "systemctl mask
> ctrl-alt-del.target". As a result, the pv reboot would not work as signal
> is ignored.
>
> This patch always enables C_A_D before the call of ctrl_alt_del() in order
> to force the reboot.
Hmm, I'm not sure this is a good idea.
Suppose a guest admin is doing a critical update and wants to avoid a
sudden reboot in between. By masking the reboot this would be possible,
with your patch it isn't.
In case a reboot is really mandatory it would still be possible to just
kill the guest.
I'm not completely opposed to the patch, but I think this is a change
which should not be done easily.
Juergen
>
> Reported-by: Rose Wang <rose.wang@oracle.com>
> Cc: Joe Jin <joe.jin@oracle.com>
> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
> ---
> drivers/xen/manage.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
> index cd046684e0d1..3190d0ecb52e 100644
> --- a/drivers/xen/manage.c
> +++ b/drivers/xen/manage.c
> @@ -204,6 +204,13 @@ static void do_poweroff(void)
> static void do_reboot(void)
> {
> shutting_down = SHUTDOWN_POWEROFF; /* ? */
> + /*
> + * The systemd may be configured to mask ctrl-alt-del via
> + * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
> + * would not work. To enable C_A_D would force the reboot.
> + */
> + C_A_D = 1;
> +
> ctrl_alt_del();
> }
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] xen/manage: enable C_A_D to force reboot
2020-05-15 7:01 ` Jürgen Groß
@ 2020-05-15 17:26 ` Boris Ostrovsky
-1 siblings, 0 replies; 6+ messages in thread
From: Boris Ostrovsky @ 2020-05-15 17:26 UTC (permalink / raw)
To: Jürgen Groß, Dongli Zhang, xen-devel, linux-kernel
Cc: sstabellini, joe.jin, rose.wang
On 5/15/20 3:01 AM, Jürgen Groß wrote:
> On 14.05.20 01:34, Dongli Zhang wrote:
>> The systemd may be configured to mask ctrl-alt-del via "systemctl mask
>> ctrl-alt-del.target". As a result, the pv reboot would not work as
>> signal
>> is ignored.
>>
>> This patch always enables C_A_D before the call of ctrl_alt_del() in
>> order
>> to force the reboot.
>
> Hmm, I'm not sure this is a good idea.
>
> Suppose a guest admin is doing a critical update and wants to avoid a
> sudden reboot in between. By masking the reboot this would be possible,
> with your patch it isn't.
>
> In case a reboot is really mandatory it would still be possible to just
> kill the guest.
>
> I'm not completely opposed to the patch, but I think this is a change
> which should not be done easily.
I think 'xl reboot -F' should do be handling this scenario but (1) it is
currently not quite set up for this and (2) I can't see how it works at
all given that noone handles LIBXL_TRIGGER_RESET in
arch_do_domctl(XEN_DOMCTL_sendtrigger).
-boris
>
>
> Juergen
>
>>
>> Reported-by: Rose Wang <rose.wang@oracle.com>
>> Cc: Joe Jin <joe.jin@oracle.com>
>> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
>> ---
>> drivers/xen/manage.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
>> index cd046684e0d1..3190d0ecb52e 100644
>> --- a/drivers/xen/manage.c
>> +++ b/drivers/xen/manage.c
>> @@ -204,6 +204,13 @@ static void do_poweroff(void)
>> static void do_reboot(void)
>> {
>> shutting_down = SHUTDOWN_POWEROFF; /* ? */
>> + /*
>> + * The systemd may be configured to mask ctrl-alt-del via
>> + * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
>> + * would not work. To enable C_A_D would force the reboot.
>> + */
>> + C_A_D = 1;
>> +
>> ctrl_alt_del();
>> }
>>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/1] xen/manage: enable C_A_D to force reboot
@ 2020-05-15 17:26 ` Boris Ostrovsky
0 siblings, 0 replies; 6+ messages in thread
From: Boris Ostrovsky @ 2020-05-15 17:26 UTC (permalink / raw)
To: Jürgen Groß, Dongli Zhang, xen-devel, linux-kernel
Cc: rose.wang, sstabellini, joe.jin
On 5/15/20 3:01 AM, Jürgen Groß wrote:
> On 14.05.20 01:34, Dongli Zhang wrote:
>> The systemd may be configured to mask ctrl-alt-del via "systemctl mask
>> ctrl-alt-del.target". As a result, the pv reboot would not work as
>> signal
>> is ignored.
>>
>> This patch always enables C_A_D before the call of ctrl_alt_del() in
>> order
>> to force the reboot.
>
> Hmm, I'm not sure this is a good idea.
>
> Suppose a guest admin is doing a critical update and wants to avoid a
> sudden reboot in between. By masking the reboot this would be possible,
> with your patch it isn't.
>
> In case a reboot is really mandatory it would still be possible to just
> kill the guest.
>
> I'm not completely opposed to the patch, but I think this is a change
> which should not be done easily.
I think 'xl reboot -F' should do be handling this scenario but (1) it is
currently not quite set up for this and (2) I can't see how it works at
all given that noone handles LIBXL_TRIGGER_RESET in
arch_do_domctl(XEN_DOMCTL_sendtrigger).
-boris
>
>
> Juergen
>
>>
>> Reported-by: Rose Wang <rose.wang@oracle.com>
>> Cc: Joe Jin <joe.jin@oracle.com>
>> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
>> Signed-off-by: Dongli Zhang <dongli.zhang@oracle.com>
>> ---
>> drivers/xen/manage.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/xen/manage.c b/drivers/xen/manage.c
>> index cd046684e0d1..3190d0ecb52e 100644
>> --- a/drivers/xen/manage.c
>> +++ b/drivers/xen/manage.c
>> @@ -204,6 +204,13 @@ static void do_poweroff(void)
>> static void do_reboot(void)
>> {
>> shutting_down = SHUTDOWN_POWEROFF; /* ? */
>> + /*
>> + * The systemd may be configured to mask ctrl-alt-del via
>> + * "systemctl mask ctrl-alt-del.target". As a result, the pv reboot
>> + * would not work. To enable C_A_D would force the reboot.
>> + */
>> + C_A_D = 1;
>> +
>> ctrl_alt_del();
>> }
>>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-05-15 17:26 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-05-13 23:34 [PATCH 1/1] xen/manage: enable C_A_D to force reboot Dongli Zhang
2020-05-13 23:34 ` Dongli Zhang
2020-05-15 7:01 ` Jürgen Groß
2020-05-15 7:01 ` Jürgen Groß
2020-05-15 17:26 ` Boris Ostrovsky
2020-05-15 17:26 ` Boris Ostrovsky
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