Re: [PATCH V5 01/12] perf/core: Add aux_pause, aux_resume, aux_start_paused
From: Andi Kleen <hidden>
Date: 2024-02-09 21:10:29
Also in:
linux-perf-users, lkml
The writes to rb->aux_in_pause_resume must be done only once. It might be possible to get away without WRITE_ONCE(), but really the compiler should be informed not to make assumptions.
What stops the NMI from firing here?
quoted
quoted
+ if (READ_ONCE(rb->aux_in_pause_resume)) + /* Guard against NMI, NMI loses here */ + goto out_restore;
<----------------------- NMI
quoted
quoted
+ WRITE_ONCE(rb->aux_in_pause_resume, 1);
Even if it isn't racy it needs a clear comment. -Andi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel