Hi Krzysztof, On 2/18/16 9:50 AM, Krzysztof Kozlowski wrote: > On 18.02.2016 17:46, Valentin Rothberg wrote: >> >> >> Hi Krzysztof, >> >> On 2/18/16 9:13 AM, Krzysztof Kozlowski wrote: >>> On 18.02.2016 17:06, Valentin Rothberg wrote: >>>> From: kbuild test robot <[email protected]> >>>> >>>> Since commit 1c6c69525b40 ("genirq: Reject bogus threaded irq requests") >>>> threaded IRQs without a primary handler need to be requested with >>>> IRQF_ONESHOT, otherwise the request will fail. >>>> >>>> So pass the IRQF_ONESHOT flag in this case. >>>> >>>> Generated by: scripts/coccinelle/misc/irqf_oneshot.cocci >>>> >>>> CC: Laxman Dewangan <[email protected]> >>>> Signed-off-by: Fengguang Wu <[email protected]> >>>> Signed-off-by: Valentin Rothberg <[email protected]> >>>> --- >>>> drivers/rtc/rtc-max77686.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>> >>> Nack, because: >>> 1. AFAIR this is a false positive. >> >> Looking at kernel/irq/manage.c +1250 such requests will be rejected >> unconditionally when the primary handler is NULL, except when the chip >> is marked to be oneshot safe. >> >> Is there another semantic that I am not aware of? In case the script >> produces false positives, I will change it immediately. > > The handler is "irq_nested_primary_handler". > >>> 2. Was it tested? Was it reproduced? Was the bug actually spotted or >>> just coccicheck pointed this and you assumed that "request will fail"? >>> >>> Coccicheck is a great tool... but not necessarily for pointing run-time >>> bugs. >> >> I did not test it. To me the issue rather seems seems like something >> where Coccinelle is really good at, static analysis. > > Yet, this is somehow subtle (device inter-dependencies) so it falls out > of static into runtime (I mean runtime analysis is needed).
Thanks for your answer. I wasn't aware of this at all. Best regards, Valentin
