Am 28.10.2010 21:34, Philippe Gerum wrote: > On Thu, 2010-10-28 at 21:15 +0200, Gilles Chanteperdrix wrote: >> Jan Kiszka wrote: >>> Gilles, >>> >>> I happened to come across rthal_mark_irq_disabled/enabled on arm. On >>> first glance, it looks like these helpers manipulate irq_desc::status >>> non-atomically, i.e. without holding irq_desc::lock. Isn't this fragile? >> >> I have no idea. How do the other architectures do? As far as I know, >> this code has been copied from there. > > Other archs do the same, simply because once an irq is managed by the > hal, it may not be shared in any way with the regular kernel. So locking > is pointless.
Indeed, I missed that all the other archs have this uninlined in hal.c. However, this leaves at least a race between xnintr_disable/enable and XN_ISR_PROPAGATE (ie. the related Linux path) behind. Not sure if it matters practically - but risking silent breakage for this micro optimization? Is disabling/enabling really in the highly latency-critical anywhere? Otherwise, I would suggest to just plug this by adding the intended lock for this field. Jan
Description: OpenPGP digital signature
_______________________________________________ Xenomai-core mailing list Xenomaifirstname.lastname@example.org https://mail.gna.org/listinfo/xenomai-core