* [PATCH] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 11:01 ` Thomas Gleixner
0 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 11:01 UTC (permalink / raw)
To: LKML; +Cc: x86, Boris Ostrovsky, Juergen Gross, Stefano Stabellini, xen-devel
xen_maybe_preempt_hcall() is called from the exception entry point
xen_do_hypervisor_callback with interrupts disabled.
_cond_resched() evades the might_sleep() check in cond_resched() which
would have caught that and schedule_debug() unfortunately lacks a check
for irqs_disabled().
Enable interrupts around the call and use cond_resched() to catch future
issues.
Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/xen/preempt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/xen/preempt.c
+++ b/drivers/xen/preempt.c
@@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
- _cond_resched();
+ local_irq_enable();
+ cond_resched();
__this_cpu_write(xen_in_preemptible_hcall, true);
+ local_irq_disable();
}
}
#endif /* CONFIG_PREEMPTION */
^ permalink raw reply [flat|nested] 10+ messages in thread* [Xen-devel] [PATCH] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 11:01 ` Thomas Gleixner
0 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 11:01 UTC (permalink / raw)
To: LKML; +Cc: Juergen Gross, xen-devel, Boris Ostrovsky, x86, Stefano Stabellini
xen_maybe_preempt_hcall() is called from the exception entry point
xen_do_hypervisor_callback with interrupts disabled.
_cond_resched() evades the might_sleep() check in cond_resched() which
would have caught that and schedule_debug() unfortunately lacks a check
for irqs_disabled().
Enable interrupts around the call and use cond_resched() to catch future
issues.
Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
drivers/xen/preempt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/xen/preempt.c
+++ b/drivers/xen/preempt.c
@@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
- _cond_resched();
+ local_irq_enable();
+ cond_resched();
__this_cpu_write(xen_in_preemptible_hcall, true);
+ local_irq_disable();
}
}
#endif /* CONFIG_PREEMPTION */
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https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] xen: Enable interrupts when calling _cond_resched()
2020-02-19 11:01 ` [Xen-devel] " Thomas Gleixner
@ 2020-02-19 12:02 ` Jürgen Groß
-1 siblings, 0 replies; 10+ messages in thread
From: Jürgen Groß @ 2020-02-19 12:02 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: x86, Boris Ostrovsky, Stefano Stabellini, xen-devel
On 19.02.20 12:01, Thomas Gleixner wrote:
> xen_maybe_preempt_hcall() is called from the exception entry point
> xen_do_hypervisor_callback with interrupts disabled.
>
> _cond_resched() evades the might_sleep() check in cond_resched() which
> would have caught that and schedule_debug() unfortunately lacks a check
> for irqs_disabled().
>
> Enable interrupts around the call and use cond_resched() to catch future
> issues.
>
> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> drivers/xen/preempt.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> --- a/drivers/xen/preempt.c
> +++ b/drivers/xen/preempt.c
> @@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
> * cpu.
> */
> __this_cpu_write(xen_in_preemptible_hcall, false);
> - _cond_resched();
> + local_irq_enable();
> + cond_resched();
> __this_cpu_write(xen_in_preemptible_hcall, true);
> + local_irq_disable();
Could you please put the call of local_irq_disable() directly after the
cond_resched() call to make the result symmetric regarding writing of
xen_in_preemptible_hcall and irq enable/disable?
Juergen
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Xen-devel] [PATCH] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 12:02 ` Jürgen Groß
0 siblings, 0 replies; 10+ messages in thread
From: Jürgen Groß @ 2020-02-19 12:02 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: xen-devel, Boris Ostrovsky, x86, Stefano Stabellini
On 19.02.20 12:01, Thomas Gleixner wrote:
> xen_maybe_preempt_hcall() is called from the exception entry point
> xen_do_hypervisor_callback with interrupts disabled.
>
> _cond_resched() evades the might_sleep() check in cond_resched() which
> would have caught that and schedule_debug() unfortunately lacks a check
> for irqs_disabled().
>
> Enable interrupts around the call and use cond_resched() to catch future
> issues.
>
> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
> drivers/xen/preempt.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> --- a/drivers/xen/preempt.c
> +++ b/drivers/xen/preempt.c
> @@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
> * cpu.
> */
> __this_cpu_write(xen_in_preemptible_hcall, false);
> - _cond_resched();
> + local_irq_enable();
> + cond_resched();
> __this_cpu_write(xen_in_preemptible_hcall, true);
> + local_irq_disable();
Could you please put the call of local_irq_disable() directly after the
cond_resched() call to make the result symmetric regarding writing of
xen_in_preemptible_hcall and irq enable/disable?
Juergen
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH] xen: Enable interrupts when calling _cond_resched()
2020-02-19 12:02 ` [Xen-devel] " Jürgen Groß
@ 2020-02-19 14:53 ` Thomas Gleixner
-1 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 14:53 UTC (permalink / raw)
To: Jürgen Groß, LKML
Cc: x86, Boris Ostrovsky, Stefano Stabellini, xen-devel
Jürgen Groß <jgross@suse.com> writes:
> On 19.02.20 12:01, Thomas Gleixner wrote:
>> xen_maybe_preempt_hcall() is called from the exception entry point
>> xen_do_hypervisor_callback with interrupts disabled.
>>
>> _cond_resched() evades the might_sleep() check in cond_resched() which
>> would have caught that and schedule_debug() unfortunately lacks a check
>> for irqs_disabled().
>>
>> Enable interrupts around the call and use cond_resched() to catch future
>> issues.
>>
>> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>> ---
>> drivers/xen/preempt.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> --- a/drivers/xen/preempt.c
>> +++ b/drivers/xen/preempt.c
>> @@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
>> * cpu.
>> */
>> __this_cpu_write(xen_in_preemptible_hcall, false);
>> - _cond_resched();
>> + local_irq_enable();
>> + cond_resched();
>> __this_cpu_write(xen_in_preemptible_hcall, true);
>> + local_irq_disable();
>
> Could you please put the call of local_irq_disable() directly after the
> cond_resched() call to make the result symmetric regarding writing of
> xen_in_preemptible_hcall and irq enable/disable?
Darn. Of course does this need to be there. Stupid me, let me resend.
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Xen-devel] [PATCH] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 14:53 ` Thomas Gleixner
0 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 14:53 UTC (permalink / raw)
To: Jürgen Groß, LKML
Cc: xen-devel, Boris Ostrovsky, x86, Stefano Stabellini
Jürgen Groß <jgross@suse.com> writes:
> On 19.02.20 12:01, Thomas Gleixner wrote:
>> xen_maybe_preempt_hcall() is called from the exception entry point
>> xen_do_hypervisor_callback with interrupts disabled.
>>
>> _cond_resched() evades the might_sleep() check in cond_resched() which
>> would have caught that and schedule_debug() unfortunately lacks a check
>> for irqs_disabled().
>>
>> Enable interrupts around the call and use cond_resched() to catch future
>> issues.
>>
>> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
>> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
>> ---
>> drivers/xen/preempt.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> --- a/drivers/xen/preempt.c
>> +++ b/drivers/xen/preempt.c
>> @@ -33,8 +33,10 @@ asmlinkage __visible void xen_maybe_pree
>> * cpu.
>> */
>> __this_cpu_write(xen_in_preemptible_hcall, false);
>> - _cond_resched();
>> + local_irq_enable();
>> + cond_resched();
>> __this_cpu_write(xen_in_preemptible_hcall, true);
>> + local_irq_disable();
>
> Could you please put the call of local_irq_disable() directly after the
> cond_resched() call to make the result symmetric regarding writing of
> xen_in_preemptible_hcall and irq enable/disable?
Darn. Of course does this need to be there. Stupid me, let me resend.
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* [PATCH V2] xen: Enable interrupts when calling _cond_resched()
2020-02-19 14:53 ` [Xen-devel] " Thomas Gleixner
@ 2020-02-19 17:30 ` Thomas Gleixner
-1 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 17:30 UTC (permalink / raw)
To: Jürgen Groß, LKML
Cc: x86, Boris Ostrovsky, Stefano Stabellini, xen-devel
xen_maybe_preempt_hcall() is called from the exception entry point
xen_do_hypervisor_callback with interrupts disabled.
_cond_resched() evades the might_sleep() check in cond_resched() which
would have caught that and schedule_debug() unfortunately lacks a check
for irqs_disabled().
Enable interrupts around the call and use cond_resched() to catch future
issues.
Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: Put local_irq_disable() where it belongs.
---
drivers/xen/preempt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/xen/preempt.c
+++ b/drivers/xen/preempt.c
@@ -33,7 +33,9 @@ asmlinkage __visible void xen_maybe_pree
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
- _cond_resched();
+ local_irq_enable();
+ cond_resched();
+ local_irq_disable();
__this_cpu_write(xen_in_preemptible_hcall, true);
}
}
^ permalink raw reply [flat|nested] 10+ messages in thread* [Xen-devel] [PATCH V2] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 17:30 ` Thomas Gleixner
0 siblings, 0 replies; 10+ messages in thread
From: Thomas Gleixner @ 2020-02-19 17:30 UTC (permalink / raw)
To: Jürgen Groß, LKML
Cc: xen-devel, Boris Ostrovsky, x86, Stefano Stabellini
xen_maybe_preempt_hcall() is called from the exception entry point
xen_do_hypervisor_callback with interrupts disabled.
_cond_resched() evades the might_sleep() check in cond_resched() which
would have caught that and schedule_debug() unfortunately lacks a check
for irqs_disabled().
Enable interrupts around the call and use cond_resched() to catch future
issues.
Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V2: Put local_irq_disable() where it belongs.
---
drivers/xen/preempt.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/xen/preempt.c
+++ b/drivers/xen/preempt.c
@@ -33,7 +33,9 @@ asmlinkage __visible void xen_maybe_pree
* cpu.
*/
__this_cpu_write(xen_in_preemptible_hcall, false);
- _cond_resched();
+ local_irq_enable();
+ cond_resched();
+ local_irq_disable();
__this_cpu_write(xen_in_preemptible_hcall, true);
}
}
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Xen-devel@lists.xenproject.org
https://lists.xenproject.org/mailman/listinfo/xen-devel
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [PATCH V2] xen: Enable interrupts when calling _cond_resched()
2020-02-19 17:30 ` [Xen-devel] " Thomas Gleixner
@ 2020-02-19 18:42 ` Jürgen Groß
-1 siblings, 0 replies; 10+ messages in thread
From: Jürgen Groß @ 2020-02-19 18:42 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: x86, Boris Ostrovsky, Stefano Stabellini, xen-devel
On 19.02.20 18:30, Thomas Gleixner wrote:
> xen_maybe_preempt_hcall() is called from the exception entry point
> xen_do_hypervisor_callback with interrupts disabled.
>
> _cond_resched() evades the might_sleep() check in cond_resched() which
> would have caught that and schedule_debug() unfortunately lacks a check
> for irqs_disabled().
>
> Enable interrupts around the call and use cond_resched() to catch future
> issues.
>
> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
^ permalink raw reply [flat|nested] 10+ messages in thread* Re: [Xen-devel] [PATCH V2] xen: Enable interrupts when calling _cond_resched()
@ 2020-02-19 18:42 ` Jürgen Groß
0 siblings, 0 replies; 10+ messages in thread
From: Jürgen Groß @ 2020-02-19 18:42 UTC (permalink / raw)
To: Thomas Gleixner, LKML; +Cc: xen-devel, Boris Ostrovsky, x86, Stefano Stabellini
On 19.02.20 18:30, Thomas Gleixner wrote:
> xen_maybe_preempt_hcall() is called from the exception entry point
> xen_do_hypervisor_callback with interrupts disabled.
>
> _cond_resched() evades the might_sleep() check in cond_resched() which
> would have caught that and schedule_debug() unfortunately lacks a check
> for irqs_disabled().
>
> Enable interrupts around the call and use cond_resched() to catch future
> issues.
>
> Fixes: fdfd811ddde3 ("x86/xen: allow privcmd hypercalls to be preempted")
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Juergen
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^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2020-02-19 18:42 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-02-19 11:01 [PATCH] xen: Enable interrupts when calling _cond_resched() Thomas Gleixner
2020-02-19 11:01 ` [Xen-devel] " Thomas Gleixner
2020-02-19 12:02 ` Jürgen Groß
2020-02-19 12:02 ` [Xen-devel] " Jürgen Groß
2020-02-19 14:53 ` Thomas Gleixner
2020-02-19 14:53 ` [Xen-devel] " Thomas Gleixner
2020-02-19 17:30 ` [PATCH V2] " Thomas Gleixner
2020-02-19 17:30 ` [Xen-devel] " Thomas Gleixner
2020-02-19 18:42 ` Jürgen Groß
2020-02-19 18:42 ` [Xen-devel] " Jürgen Groß
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