On Tue, Jun 23, 2020 at 06:13:21PM +0200, Ahmed S. Darwish wrote:
> Well, freshly merged code is using it. For example, KCSAN:
>
> => f1bc96210c6a ("kcsan: Make KCSAN compatible with lockdep")
> => kernel/kcsan/report.c:
>
> void kcsan_report(...)
> {
> ...
> /*
> * With TRACE_IRQFLAGS, lockdep's IRQ trace state becomes corrupted if
> * we do not turn off lockdep here; this could happen due to recursion
> * into lockdep via KCSAN if we detect a race in utilities used by
> * lockdep.
> */
> lockdep_off();
> ...
> }
Marco, do you remember what exactly happened there? Because I'm about to
wreck that. That is, I'm going to make TRACE_IRQFLAGS ignore
lockdep_off().
