From: Jinpu Wang <jinpu.wang@ionos.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Jack Wang <jinpu.wang@cloud.ionos.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Arnd Bergmann <arnd@arndb.de>, Viswas G <Viswas.G@microchip.com>,
Ruksar Devadi <Ruksar.devadi@microchip.com>,
Joe Perches <joe@perches.com>,
Vaibhav Gupta <vaibhavgupta40@gmail.com>,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
Lee Jones <lee.jones@linaro.org>,
Linux SCSI Mailinglist <linux-scsi@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] scsi: pm8001: avoid -Wrestrict warning
Date: Wed, 24 Mar 2021 11:56:39 +0100 [thread overview]
Message-ID: <CAMGffEnahDx9cR+GUmvXZT0ztq+uLC+Yn-_nMVOf452uwx8Q6A@mail.gmail.com> (raw)
In-Reply-To: <20210323125458.1825564-1-arnd@kernel.org>
On Tue, Mar 23, 2021 at 1:55 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> On some configurations, gcc warns about overlapping source and
> destination arguments to snprintf:
>
> drivers/scsi/pm8001/pm8001_init.c: In function 'pm8001_request_msix':
> drivers/scsi/pm8001/pm8001_init.c:977:3: error: 'snprintf' argument 4 may overlap destination object 'pm8001_ha' [-Werror=restrict]
> 977 | snprintf(drvname, len, "%s-%d", pm8001_ha->name, i);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/scsi/pm8001/pm8001_init.c:962:56: note: destination object referenced by 'restrict'-qualified argument 1 was declared here
> 962 | static u32 pm8001_request_msix(struct pm8001_hba_info *pm8001_ha)
> | ~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~
>
> I first assumed this was a gcc bug, as that should not happen, but
> a reduced test case makes it clear that this happens when the loop
> counter is not bounded by the array size.
>
> Help the compiler out by adding an explicit limit here to make the
> code slightly more robust and avoid the warning.
>
> Link: https://godbolt.org/z/6T1qPM
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jack Wang <jinpu.wang@ionos.com>
> ---
> drivers/scsi/pm8001/pm8001_init.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
> index bd626ef876da..a268c647b987 100644
> --- a/drivers/scsi/pm8001/pm8001_init.c
> +++ b/drivers/scsi/pm8001/pm8001_init.c
> @@ -963,6 +963,7 @@ static u32 pm8001_request_msix(struct pm8001_hba_info *pm8001_ha)
> {
> u32 i = 0, j = 0;
> int flag = 0, rc = 0;
> + int nr_irqs = pm8001_ha->number_of_intr;
>
> if (pm8001_ha->chip_id != chip_8001)
> flag &= ~IRQF_SHARED;
> @@ -971,7 +972,10 @@ static u32 pm8001_request_msix(struct pm8001_hba_info *pm8001_ha)
> "pci_enable_msix request number of intr %d\n",
> pm8001_ha->number_of_intr);
>
> - for (i = 0; i < pm8001_ha->number_of_intr; i++) {
> + if (nr_irqs > ARRAY_SIZE(pm8001_ha->intr_drvname))
> + nr_irqs = ARRAY_SIZE(pm8001_ha->intr_drvname);
> +
> + for (i = 0; i < nr_irqs; i++) {
> snprintf(pm8001_ha->intr_drvname[i],
> sizeof(pm8001_ha->intr_drvname[0]),
> "%s-%d", pm8001_ha->name, i);
> --
> 2.29.2
>
next prev parent reply other threads:[~2021-03-24 10:57 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-23 12:54 [PATCH] scsi: pm8001: avoid -Wrestrict warning Arnd Bergmann
2021-03-24 10:56 ` Jinpu Wang [this message]
2021-03-30 3:54 ` Martin K. Petersen
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