On 20.04.2022 10:13, David Vrabel wrote: > > > On 20/04/2022 07:26, Jan Beulich wrote: >> On 19.04.2022 17:01, David Vrabel wrote: >>> From: David Vrabel <dvra...@amazon.co.uk> >>> >>> Heap pages can only be safely allocated and freed with interuupts >>> enabled as they may require a TLB flush which will send IPIs. >>> >>> Enhance the assertions in alloc_xenheap_pages() and >>> alloc_domheap_pages() to check interrupts are enabled. For consistency >>> the same asserts are used when freeing heap pages. >>> >>> As an exception, during early boot when only 1 PCPU is online, >>> allocations are permitted with interrupts disabled. >> >> This exception is tightly coupled with spin lock checking, i.e. the >> point in time when spin_debug_enable() is called. I think this wants >> making explicit at least in the code comment, but as a result I also >> wonder in how far the extended assertions are really worthwhile: Any >> violation would be detected in check_lock() anyway. Thoughts? > > I was caught out by stop_machine_run() disabling both interrupts and > spin lock debugging when running the action function, so check_lock() > didn't help in this (admittedly) narrow use case.
Oh, I see - fair point. Jan >> Furthermore I'm concerned of Arm not using either SYS_STATE_smp_boot >> or spin_debug_enable(). > > David >
