2021-08-25 13:42:56

by Jürgen Groß

Subject: [PATCH] xen: remove stray preempt_disable() from PV AP startup code

In cpu_bringup() there is a call of preempt_disable() without a paired
preempt_enable(). This is not needed as interrupts are off initially.
Additionally this will result in early boot messages like:

BUG: scheduling while atomic: swapper/1/0/0x00000002

Signed-off-by: Juergen Gross <[email protected]>
---
arch/x86/xen/smp_pv.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
index c2ac319f11a4..96afadf9878e 100644
--- a/arch/x86/xen/smp_pv.c
+++ b/arch/x86/xen/smp_pv.c
@@ -64,7 +64,6 @@ static void cpu_bringup(void)
cr4_init();
cpu_init();
touch_softlockup_watchdog();
- preempt_disable();

/* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {
--
2.26.2

2021-09-08 15:00:37

by Boris Ostrovsky

Subject: Re: [PATCH] xen: remove stray preempt_disable() from PV AP startup code

On 8/25/21 7:31 AM, Juergen Gross wrote:
> In cpu_bringup() there is a call of preempt_disable() without a paired
> preempt_enable(). This is not needed as interrupts are off initially.
> Additionally this will result in early boot messages like:
>
> BUG: scheduling while atomic: swapper/1/0/0x00000002
>
> Signed-off-by: Juergen Gross <[email protected]>


Reviewed-by: Boris Ostrovsky <[email protected]>