From: Thomas Gleixner <tglx@linutronix.de> To: "Jürgen Groß" <jgross@suse.com>, LKML <linux-kernel@vger.kernel.org> Cc: x86@kernel.org, Boris Ostrovsky <boris.ostrovsky@oracle.com>, Stefano Stabellini <sstabellini@kernel.org>, xen-devel@lists.xenproject.org Subject: [PATCH V2] xen: Enable interrupts when calling _cond_resched() Date: Wed, 19 Feb 2020 18:30:26 +0100 [thread overview] Message-ID: <878skypjrh.fsf@nanos.tec.linutronix.de> (raw) In-Reply-To: <87h7zmpr1k.fsf@nanos.tec.linutronix.de> 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); } }
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de> To: "Jürgen Groß" <jgross@suse.com>, LKML <linux-kernel@vger.kernel.org> Cc: xen-devel@lists.xenproject.org, Boris Ostrovsky <boris.ostrovsky@oracle.com>, x86@kernel.org, Stefano Stabellini <sstabellini@kernel.org> Subject: [Xen-devel] [PATCH V2] xen: Enable interrupts when calling _cond_resched() Date: Wed, 19 Feb 2020 18:30:26 +0100 [thread overview] Message-ID: <878skypjrh.fsf@nanos.tec.linutronix.de> (raw) In-Reply-To: <87h7zmpr1k.fsf@nanos.tec.linutronix.de> 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); } } _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
next prev parent reply other threads:[~2020-02-19 17:30 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 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 ` Thomas Gleixner [this message] 2020-02-19 17:30 ` [Xen-devel] [PATCH V2] " Thomas Gleixner 2020-02-19 18:42 ` Jürgen Groß 2020-02-19 18:42 ` [Xen-devel] " Jürgen Groß
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