[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH] sched: fix scheduler_disable() with core scheduling

On 09.04.20 11:41, Sergey Dyasli wrote:
In core-scheduling mode, Xen might crash when entering ACPI S5 state.
This happens in sched_slave() during is_idle_unit(next) check because
next->vcpu_list is stale and points to an already freed memory.

This situation happens shortly after scheduler_disable() is called if
some CPU is still inside sched_slave() softirq. Current logic simply
returns prev->next_task from sched_wait_rendezvous_in() which causes
the described crash because next_task->vcpu_list has become invalid.

Fix the crash by returning NULL from sched_wait_rendezvous_in() in
the case when scheduler_disable() has been called.

Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx>

Good catch!

Have you seen any further problems (e.g. with cpu on/offlining) with
this patch applied?

Reviewed-by: Juergen Gross <jgross@xxxxxxxx>




Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.