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* [PATCH] xen: remove stray preempt_disable() from PV AP startup code
@ 2021-08-25 11:31 Juergen Gross
  2021-09-08 14:21 ` Boris Ostrovsky
  0 siblings, 1 reply; 2+ messages in thread
From: Juergen Gross @ 2021-08-25 11:31 UTC (permalink / raw)
  To: xen-devel, x86, linux-kernel
  Cc: Juergen Gross, Boris Ostrovsky, Stefano Stabellini,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin

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 <jgross@suse.com>
---
 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


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [PATCH] xen: remove stray preempt_disable() from PV AP startup code
  2021-08-25 11:31 [PATCH] xen: remove stray preempt_disable() from PV AP startup code Juergen Gross
@ 2021-09-08 14:21 ` Boris Ostrovsky
  0 siblings, 0 replies; 2+ messages in thread
From: Boris Ostrovsky @ 2021-09-08 14:21 UTC (permalink / raw)
  To: Juergen Gross, xen-devel, x86, linux-kernel
  Cc: Stefano Stabellini, Thomas Gleixner, Ingo Molnar,
	Borislav Petkov, H. Peter Anvin


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 <jgross@suse.com>


Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>



^ permalink raw reply	[flat|nested] 2+ messages in thread

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2021-08-25 11:31 [PATCH] xen: remove stray preempt_disable() from PV AP startup code Juergen Gross
2021-09-08 14:21 ` Boris Ostrovsky

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