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 <t...@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
