From: Julia Lawall <julia.lawall@inria.fr> To: Daniel Thompson <daniel.thompson@linaro.org> Cc: Gilles Muller <Gilles.Muller@inria.fr>, Nicolas Palix <nicolas.palix@imag.fr>, Michal Marek <michal.lkml@markovi.net>, cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org Subject: Re: [PATCH] scripts: coccinelle: allow list_entry_is_head() to use pos Date: Fri, 30 Jul 2021 12:58:40 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.22.394.2107301257470.52326@hadrien> (raw) In-Reply-To: <20210730095856.2038286-1-daniel.thompson@linaro.org> On Fri, 30 Jul 2021, Daniel Thompson wrote: > Currently use_after_iter.cocci generates false positives for code of the > following form: > ~~~ > list_for_each_entry(d, &ddata->irq_list, node) { > if (irq == d->irq) > break; > } > > if (list_entry_is_head(d, &ddata->irq_list, node)) > return IRQ_NONE; > ~~~ > [This specific example comes from drivers/power/supply/cpcap-battery.c] > > Most list macros use list_entry_is_head() as loop exit condition meaning it > is not unsafe to reuse pos (a.k.a. d) in the code above. > > Let's avoid reporting these cases. > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > --- > > Notes: > I'm pretty much a complete beginner w.r.t. SmPL. This is written > entirely by finding previous fixes and emulating them! > > However I did test it by running the checker across the current kernel > tree. The changes reduced the error count by four... which was small > enough for me to eyeball each one and check they match the pattern I > was targetting. This looks fine. Thanks for the proposal. julia > > scripts/coccinelle/iterators/use_after_iter.cocci | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/scripts/coccinelle/iterators/use_after_iter.cocci b/scripts/coccinelle/iterators/use_after_iter.cocci > index 9be48b520879..676edd562eef 100644 > --- a/scripts/coccinelle/iterators/use_after_iter.cocci > +++ b/scripts/coccinelle/iterators/use_after_iter.cocci > @@ -123,6 +123,8 @@ hlist_for_each_entry_safe(c,...) S > | > list_remove_head(x,c,...) > | > +list_entry_is_head(c,...) > +| > sizeof(<+...c...+>) > | > &c->member > > base-commit: 2734d6c1b1a089fb593ef6a23d4b70903526fe0c > -- > 2.30.2 > >
WARNING: multiple messages have this Message-ID (diff)
From: Julia Lawall <julia.lawall@inria.fr> To: Daniel Thompson <daniel.thompson@linaro.org> Cc: Michal Marek <michal.lkml@markovi.net>, Nicolas Palix <nicolas.palix@imag.fr>, cocci@systeme.lip6.fr, linux-kernel@vger.kernel.org Subject: Re: [Cocci] [PATCH] scripts: coccinelle: allow list_entry_is_head() to use pos Date: Fri, 30 Jul 2021 12:58:40 +0200 (CEST) [thread overview] Message-ID: <alpine.DEB.2.22.394.2107301257470.52326@hadrien> (raw) In-Reply-To: <20210730095856.2038286-1-daniel.thompson@linaro.org> On Fri, 30 Jul 2021, Daniel Thompson wrote: > Currently use_after_iter.cocci generates false positives for code of the > following form: > ~~~ > list_for_each_entry(d, &ddata->irq_list, node) { > if (irq == d->irq) > break; > } > > if (list_entry_is_head(d, &ddata->irq_list, node)) > return IRQ_NONE; > ~~~ > [This specific example comes from drivers/power/supply/cpcap-battery.c] > > Most list macros use list_entry_is_head() as loop exit condition meaning it > is not unsafe to reuse pos (a.k.a. d) in the code above. > > Let's avoid reporting these cases. > > Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> > --- > > Notes: > I'm pretty much a complete beginner w.r.t. SmPL. This is written > entirely by finding previous fixes and emulating them! > > However I did test it by running the checker across the current kernel > tree. The changes reduced the error count by four... which was small > enough for me to eyeball each one and check they match the pattern I > was targetting. This looks fine. Thanks for the proposal. julia > > scripts/coccinelle/iterators/use_after_iter.cocci | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/scripts/coccinelle/iterators/use_after_iter.cocci b/scripts/coccinelle/iterators/use_after_iter.cocci > index 9be48b520879..676edd562eef 100644 > --- a/scripts/coccinelle/iterators/use_after_iter.cocci > +++ b/scripts/coccinelle/iterators/use_after_iter.cocci > @@ -123,6 +123,8 @@ hlist_for_each_entry_safe(c,...) S > | > list_remove_head(x,c,...) > | > +list_entry_is_head(c,...) > +| > sizeof(<+...c...+>) > | > &c->member > > base-commit: 2734d6c1b1a089fb593ef6a23d4b70903526fe0c > -- > 2.30.2 > > _______________________________________________ Cocci mailing list Cocci@systeme.lip6.fr https://systeme.lip6.fr/mailman/listinfo/cocci
next prev parent reply other threads:[~2021-07-30 10:58 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-30 9:58 [PATCH] scripts: coccinelle: allow list_entry_is_head() to use pos Daniel Thompson 2021-07-30 9:58 ` [Cocci] " Daniel Thompson 2021-07-30 10:58 ` Julia Lawall [this message] 2021-07-30 10:58 ` Julia Lawall 2021-08-08 20:02 ` Julia Lawall
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