From: William Breathitt Gray <william.gray@linaro.org>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Biju Das <biju.das.jz@bp.renesas.com>, Lee Jones <lee@kernel.org>,
linux-iio@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] counter: rz-mtu3-cnt: Unlock on error in rz_mtu3_count_write()
Date: Wed, 19 Apr 2023 11:30:30 -0400 [thread overview]
Message-ID: <ZEAJFnNiAE+L5ht4@fedora> (raw)
In-Reply-To: <0859b9d5-c504-4f46-83ad-dcd7ada6b81b@kili.mountain>
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On Wed, Apr 19, 2023 at 06:37:05PM +0300, Dan Carpenter wrote:
> On Wed, Apr 19, 2023 at 10:36:49AM -0400, William Breathitt Gray wrote:
> > The lock is acquired by rz_mtu3_lock_if_counter_is_valid(), so that
> > function needs a sparse __acquires(&priv->lock) annotation too.
>
> I found this bug using Smatch. It's a competing static checker which
> uses Sparse as a parser. I am the author of Smatch so I am naturally
> biased.
>
> I don't think it's as simple as that. I don't think Sparse has
> annotations for mutexes, only for spinlocks? Also it's really
> complicated to annotate something as taking the lock on the success path
> but not on the failure path. You have to set up a wrapper and use
> __cond_lock().
>
> Every other feature in Sparse is awesome, but for locking, it's better
> to just use Smatch.
>
> regards,
> dan carpenter
Ah that's a fair point, I can see how involved that would be to set up a
wrapper and handle the various paths correctly. The marginal benefit
just doesn't seem worth the effort afterall.
William Breathitt Gray
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next prev parent reply other threads:[~2023-04-19 15:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-19 14:23 [PATCH] counter: rz-mtu3-cnt: Unlock on error in rz_mtu3_count_write() Dan Carpenter
2023-04-19 14:36 ` William Breathitt Gray
2023-04-19 15:37 ` Dan Carpenter
2023-04-19 15:30 ` William Breathitt Gray [this message]
2023-04-20 6:04 ` Biju Das
2023-04-20 14:17 ` William Breathitt Gray
2023-04-20 14:58 ` Dan Carpenter
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