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[SRU,FOCAL/linux-azure,BIONIC/linux-azure-4.15,1/1] Drivers: hv: vmbus: Only notify Hyper-V for die events that are oops

Message ID 20200818184303.56912-2-william.gray@canonical.com
State New
Headers show
Series SF 290881 Only notify Hyper-V for die events that are oops | expand

Commit Message

William Breathitt Gray Aug. 18, 2020, 6:43 p.m. UTC 
From: Michael Kelley <mikelley@microsoft.com>

Hyper-V currently may be notified of a panic for any die event. But
this results in false panic notifications for various user space traps
that are die events. Fix this by ignoring die events that aren't oops.

Fixes: 510f7aef65bb ("Drivers: hv: vmbus: prefer 'die' notification chain to 'panic'")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/1596730935-11564-1-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>

BugLink: https://bugs.launchpad.net/bugs/1891222

(cherry picked from commit 608a973bd52ef1705941b18f55e39655fcfe9cdb)
Signed-off-by: William Breathitt Gray <william.gray@canonical.com>
---
 drivers/hv/vmbus_drv.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Thadeu Lima de Souza Cascardo Aug. 18, 2020, 7:50 p.m. UTC | #1 
On Tue, Aug 18, 2020 at 02:43:03PM -0400, William Breathitt Gray wrote:
> From: Michael Kelley <mikelley@microsoft.com>
> 
> Hyper-V currently may be notified of a panic for any die event. But
> this results in false panic notifications for various user space traps
> that are die events. Fix this by ignoring die events that aren't oops.
> 
> Fixes: 510f7aef65bb ("Drivers: hv: vmbus: prefer 'die' notification chain to 'panic'")
> Signed-off-by: Michael Kelley <mikelley@microsoft.com>
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> Link: https://lore.kernel.org/r/1596730935-11564-1-git-send-email-mikelley@microsoft.com
> Signed-off-by: Wei Liu <wei.liu@kernel.org>
> 
> BugLink: https://bugs.launchpad.net/bugs/1891222

So, assuming this will be tested by Microsoft, but please have them document
the test case (what to look for on a Hyper-V UI), and what are the risks of
missing events here or what else could be broken by this. So, basically, please
get the SRU template filled up in the bug.

Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

> 
> (cherry picked from commit 608a973bd52ef1705941b18f55e39655fcfe9cdb)
> Signed-off-by: William Breathitt Gray <william.gray@canonical.com>
> ---
>  drivers/hv/vmbus_drv.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index 0f168f0b1a8f..c97f1964d9ed 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -97,6 +97,10 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
>  	struct die_args *die = (struct die_args *)args;
>  	struct pt_regs *regs = die->regs;
>  
> +	/* Don't notify Hyper-V if the die event is other than oops */
> +	if (val != DIE_OOPS)
> +		return NOTIFY_DONE;
> +
>  	/*
>  	 * Hyper-V should be notified only once about a panic.  If we will be
>  	 * doing hyperv_report_panic_msg() later with kmsg data, don't do
> -- 
> 2.25.1
> 
> 
> -- 
> kernel-team mailing list
> kernel-team@lists.ubuntu.com
> https://lists.ubuntu.com/mailman/listinfo/kernel-team
diff mbox series

Patch

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 0f168f0b1a8f..c97f1964d9ed 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -97,6 +97,10 @@  static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
 	struct die_args *die = (struct die_args *)args;
 	struct pt_regs *regs = die->regs;
 
+	/* Don't notify Hyper-V if the die event is other than oops */
+	if (val != DIE_OOPS)
+		return NOTIFY_DONE;
+
 	/*
 	 * Hyper-V should be notified only once about a panic.  If we will be
 	 * doing hyperv_report_panic_msg() later with kmsg data, don't do