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    SubjectRe: [PATCH] rtc: max77686: fix irqf_oneshot.cocci warnings
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    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 <fengguang.wu@intel.com>
    >>>
    >>> 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 <ldewangan@nvidia.com>
    >>> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
    >>> Signed-off-by: Valentin Rothberg <valentin.rothberg@posteo.net>
    >>> ---
    >>> 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).

    Best regards,
    Krzysztof

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