[PATCH 0/9] enabled -Wformat-truncation for clang

[PATCH 0/9] enabled -Wformat-truncation for clang

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

With randconfig build testing, I found only eight files that produce
warnings with clang when -Wformat-truncation is enabled. This means
we can just turn it on by default rather than only enabling it for
"make W=1".

Unfortunately, gcc produces a lot more warnings when the option
is enabled, so it's not yet possible to turn it on both both
compilers.

I hope that the patches can get picked up by platform maintainers
directly, so the final patch can go in later on.

     Arnd

Arnd Bergmann (9):
  fbdev: shmobile: fix snprintf truncation
  enetc: avoid truncating error message
  qed: avoid truncating work queue length
  mlx5: avoid truncating error message
  surface3_power: avoid format string truncation warning
  Input: IMS: fix printf string overflow
  scsi: mylex: fix sysfs buffer lengths
  ALSA: aoa: avoid false-positive format truncation warning
  kbuild: enable -Wformat-truncation on clang

 drivers/input/misc/ims-pcu.c                  |  4 ++--
 drivers/net/ethernet/freescale/enetc/enetc.c  |  2 +-
 .../ethernet/mellanox/mlx5/core/esw/bridge.c  |  2 +-
 drivers/net/ethernet/qlogic/qed/qed_main.c    |  9 ++++---
 drivers/platform/surface/surface3_power.c     |  2 +-
 drivers/scsi/myrb.c                           | 20 ++++++++--------
 drivers/scsi/myrs.c                           | 24 +++++++++----------
 drivers/video/fbdev/sh_mobile_lcdcfb.c        |  2 +-
 scripts/Makefile.extrawarn                    |  2 ++
 sound/aoa/soundbus/i2sbus/core.c              |  2 +-
 10 files changed, 35 insertions(+), 34 deletions(-)

-- 
2.39.2

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Vladimir Oltean <vladimir.oltean@nxp.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Ariel Elior <aelior@marvell.com>
Cc: Manish Chopra <manishc@marvell.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
Cc: Maximilian Luz <luzmaximilian@gmail.com>
Cc: Hannes Reinecke <hare@kernel.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Justin Stitt <justinstitt@google.com>
Cc: linux-input@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: linux-rdma@vger.kernel.org
Cc: platform-driver-x86@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: linux-fbdev@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kbuild@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: alsa-devel@alsa-project.org
Cc: linux-sound@vger.kernel.org
Cc: llvm@lists.linux.dev

[PATCH 2/9] enetc: avoid truncating error message

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

As clang points out, the error message in enetc_setup_xdp_prog()
still does not fit in the buffer and will be truncated:

drivers/net/ethernet/freescale/enetc/enetc.c:2771:3: error: 'snprintf' will always be truncated; specified size is 80, but format string expands to at least 87 [-Werror,-Wformat-truncation]

Replace it with an even shorter message that should fit.

Fixes: f968c56417f0 ("net: enetc: shorten enetc_setup_xdp_prog() error message to fit NETLINK_MAX_FMTMSG_LEN")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/freescale/enetc/enetc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 9f07f4947b63..5c45f42232d3 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -2769,7 +2769,7 @@ static int enetc_setup_xdp_prog(struct net_device *ndev, struct bpf_prog *prog,
 	if (priv->min_num_stack_tx_queues + num_xdp_tx_queues >
 	    priv->num_tx_rings) {
 		NL_SET_ERR_MSG_FMT_MOD(extack,
-				       "Reserving %d XDP TXQs does not leave a minimum of %d for stack (total %d)",
+				       "Reserving %d XDP TXQs leaves under %d for stack (total %d)",
 				       num_xdp_tx_queues,
 				       priv->min_num_stack_tx_queues,
 				       priv->num_tx_rings);
-- 
2.39.2

[PATCH 3/9] qed: avoid truncating work queue length

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

clang complains that the temporary string for the name passed into
alloc_workqueue() is too short for its contents:

drivers/net/ethernet/qlogic/qed/qed_main.c:1218:3: error: 'snprintf' will always be truncated; specified size is 16, but format string expands to at least 18 [-Werror,-Wformat-truncation]

There is no need for a temporary buffer, and the actual name of a workqueue
is 32 bytes (WQ_NAME_LEN), so just use the interface as intended to avoid
the truncation.

Fixes: 59ccf86fe69a ("qed: Add driver infrastucture for handling mfw requests.")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/qlogic/qed/qed_main.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_main.c b/drivers/net/ethernet/qlogic/qed/qed_main.c
index c278f8893042..8159b4c315b5 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_main.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_main.c
@@ -1206,7 +1206,6 @@ static void qed_slowpath_task(struct work_struct *work)
 static int qed_slowpath_wq_start(struct qed_dev *cdev)
 {
 	struct qed_hwfn *hwfn;
-	char name[NAME_SIZE];
 	int i;
 
 	if (IS_VF(cdev))
@@ -1215,11 +1214,11 @@ static int qed_slowpath_wq_start(struct qed_dev *cdev)
 	for_each_hwfn(cdev, i) {
 		hwfn = &cdev->hwfns[i];
 
-		snprintf(name, NAME_SIZE, "slowpath-%02x:%02x.%02x",
-			 cdev->pdev->bus->number,
-			 PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id);
+		hwfn->slowpath_wq = alloc_workqueue("slowpath-%02x:%02x.%02x",
+					 0, 0, cdev->pdev->bus->number,
+					 PCI_SLOT(cdev->pdev->devfn),
+					 hwfn->abs_pf_id);
 
-		hwfn->slowpath_wq = alloc_workqueue(name, 0, 0);
 		if (!hwfn->slowpath_wq) {
 			DP_NOTICE(hwfn, "Cannot create slowpath workqueue\n");
 			return -ENOMEM;
-- 
2.39.2

RE: [EXTERNAL] [PATCH 3/9] qed: avoid truncating work queue length

[Subbaraya Sundeep Bhatta]

Hi,

>-----Original Message-----
>From: Arnd Bergmann <arnd@kernel.org>
>Sent: Wednesday, March 27, 2024 4:08 AM
>To: llvm@lists.linux.dev; Ariel Elior <aelior@marvell.com>; Manish Chopra
><manishc@marvell.com>
>Cc: Arnd Bergmann <arnd@arndb.de>; David S. Miller <davem@davemloft.net>;
>Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
>Abeni <pabeni@redhat.com>; Nathan Chancellor <nathan@kernel.org>; Nick
>Desaulniers <ndesaulniers@google.com>; Bill Wendling <morbo@google.com>;
>Justin Stitt <justinstitt@google.com>; Simon Horman <horms@kernel.org>;
>Konstantin Khorenko <khorenko@virtuozzo.com>; Sudarsana Reddy Kalluru
><sudarsana.kalluru@cavium.com>; netdev@vger.kernel.org; linux-
>kernel@vger.kernel.org
>Subject: [PATCH 3/9] qed: avoid truncating work queue length
>
>From: Arnd Bergmann <arnd@arndb.de>
>
>clang complains that the temporary string for the name passed into
>alloc_workqueue() is too short for its contents:
>
>drivers/net/ethernet/qlogic/qed/qed_main.c:1218:3: error: 'snprintf' will always
>be truncated; specified size is 16, but format string expands to at least 18 [-
>Werror,-Wformat-truncation]
>
>There is no need for a temporary buffer, and the actual name of a workqueue	
>is 32 bytes (WQ_NAME_LEN), so just use the interface as intended to avoid
>the truncation.
>
>Fixes: 59ccf86fe69a ("qed: Add driver infrastucture for handling mfw requests.")
>Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>---
> drivers/net/ethernet/qlogic/qed/qed_main.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
>diff --git a/drivers/net/ethernet/qlogic/qed/qed_main.c
>b/drivers/net/ethernet/qlogic/qed/qed_main.c
>index c278f8893042..8159b4c315b5 100644
>--- a/drivers/net/ethernet/qlogic/qed/qed_main.c
>+++ b/drivers/net/ethernet/qlogic/qed/qed_main.c
>@@ -1206,7 +1206,6 @@ static void qed_slowpath_task(struct work_struct
>*work)
> static int qed_slowpath_wq_start(struct qed_dev *cdev)
> {
> 	struct qed_hwfn *hwfn;
>-	char name[NAME_SIZE];
> 	int i;
>
> 	if (IS_VF(cdev))
>@@ -1215,11 +1214,11 @@ static int qed_slowpath_wq_start(struct qed_dev
>*cdev)
> 	for_each_hwfn(cdev, i) {
> 		hwfn = &cdev->hwfns[i];
>
>-		snprintf(name, NAME_SIZE, "slowpath-%02x:%02x.%02x",
>-			 cdev->pdev->bus->number,
>-			 PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id);
>+		hwfn->slowpath_wq = alloc_workqueue("slowpath-
>%02x:%02x.%02x",
>+					 0, 0, cdev->pdev->bus->number,
>+					 PCI_SLOT(cdev->pdev->devfn),
>+					 hwfn->abs_pf_id);

Confused. This should be alloc_workqueue("slowpath-%02x:%02x.%02x",  cdev->pdev->bus->number, PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id, 0, 0);
Right?

Thanks,
Sundeep
>
>-		hwfn->slowpath_wq = alloc_workqueue(name, 0, 0);
> 		if (!hwfn->slowpath_wq) {
> 			DP_NOTICE(hwfn, "Cannot create slowpath
>workqueue\n");
> 			return -ENOMEM;
>--
>2.39.2
>

Re: [EXTERNAL] [PATCH 3/9] qed: avoid truncating work queue length

[Arnd Bergmann]

On Wed, Mar 27, 2024, at 15:04, Subbaraya Sundeep Bhatta wrote:

>>-		snprintf(name, NAME_SIZE, "slowpath-%02x:%02x.%02x",
>>-			 cdev->pdev->bus->number,
>>-			 PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id);
>>+		hwfn->slowpath_wq = alloc_workqueue("slowpath-
>>%02x:%02x.%02x",
>>+					 0, 0, cdev->pdev->bus->number,
>>+					 PCI_SLOT(cdev->pdev->devfn),
>>+					 hwfn->abs_pf_id);
>
> Confused. This should be alloc_workqueue("slowpath-%02x:%02x.%02x",  
> cdev->pdev->bus->number, PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id, 
> 0, 0);
> Right?

I still think my version is the right one here, see the
prototype:

__printf(1, 4) struct workqueue_struct *
alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);

so the first argument in the format, while the printf arguments
start after the flags and max_active arguments that are still both
set to zero.

      Arnd

RE: [EXTERNAL] [PATCH 3/9] qed: avoid truncating work queue length

[Subbaraya Sundeep Bhatta]

Hi,

>-----Original Message-----
>From: Arnd Bergmann <arnd@arndb.de>
>Sent: Wednesday, March 27, 2024 9:05 PM
>To: Subbaraya Sundeep Bhatta <sbhatta@marvell.com>; Arnd Bergmann
><arnd@kernel.org>; llvm@lists.linux.dev; Ariel Elior <aelior@marvell.com>;
>Manish Chopra <manishc@marvell.com>
>Cc: David S . Miller <davem@davemloft.net>; Eric Dumazet
><edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni
><pabeni@redhat.com>; Nathan Chancellor <nathan@kernel.org>; Nick
>Desaulniers <ndesaulniers@google.com>; Bill Wendling <morbo@google.com>;
>Justin Stitt <justinstitt@google.com>; Simon Horman <horms@kernel.org>;
>Konstantin Khorenko <khorenko@virtuozzo.com>; Sudarsana Reddy Kalluru
><sudarsana.kalluru@cavium.com>; Netdev <netdev@vger.kernel.org>; linux-
>kernel@vger.kernel.org
>Subject: Re: [EXTERNAL] [PATCH 3/9] qed: avoid truncating work queue length
>
>On Wed, Mar 27, 2024, at 15:04, Subbaraya Sundeep Bhatta wrote:
>
>>>-		snprintf(name, NAME_SIZE, "slowpath-%02x:%02x.%02x",
>>>-			 cdev->pdev->bus->number,
>>>-			 PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id);
>>>+		hwfn->slowpath_wq = alloc_workqueue("slowpath-
>>>%02x:%02x.%02x",
>>>+					 0, 0, cdev->pdev->bus->number,
>>>+					 PCI_SLOT(cdev->pdev->devfn),
>>>+					 hwfn->abs_pf_id);
>>
>> Confused. This should be alloc_workqueue("slowpath-%02x:%02x.%02x",
>> cdev->pdev->bus->number, PCI_SLOT(cdev->pdev->devfn), hwfn->abs_pf_id,
>> 0, 0);
>> Right?
>
>I still think my version is the right one here, see the
>prototype:
>
>__printf(1, 4) struct workqueue_struct *
>alloc_workqueue(const char *fmt, unsigned int flags, int max_active, ...);
>
>so the first argument in the format, while the printf arguments
>start after the flags and max_active arguments that are still both
>set to zero.
>
My bad. Got it

Thanks,
Sundeep

>      Arnd

[PATCH 4/9] mlx5: avoid truncating error message

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

clang warns that one error message is too long for its destination buffer:

drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c:1876:4: error: 'snprintf' will always be truncated; specified size is 80, but format string expands to at least 94 [-Werror,-Wformat-truncation-non-kprintf]

Reword it to be a bit shorter so it always fits.

Fixes: 70f0302b3f20 ("net/mlx5: Bridge, implement mdb offload")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
index 1b9bc32efd6f..c5ea1d1d2b03 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
@@ -1874,7 +1874,7 @@ int mlx5_esw_bridge_port_mdb_add(struct net_device *dev, u16 vport_num, u16 esw_
 				 "Failed to lookup bridge port vlan metadata to create MDB (MAC=%pM,vid=%u,vport=%u)\n",
 				 addr, vid, vport_num);
 			NL_SET_ERR_MSG_FMT_MOD(extack,
-					       "Failed to lookup bridge port vlan metadata to create MDB (MAC=%pM,vid=%u,vport=%u)\n",
+					       "Failed to lookup vlan metadata for MDB (MAC=%pM,vid=%u,vport=%u)\n",
 					       addr, vid, vport_num);
 			return -EINVAL;
 		}
-- 
2.39.2

RE: [EXTERNAL] [PATCH 4/9] mlx5: avoid truncating error message

[Subbaraya Sundeep Bhatta]

Hi,

>-----Original Message-----
>From: Arnd Bergmann <arnd@kernel.org>
>Sent: Wednesday, March 27, 2024 4:08 AM
>To: llvm@lists.linux.dev; Saeed Mahameed <saeedm@nvidia.com>; Leon
>Romanovsky <leon@kernel.org>
>Cc: Arnd Bergmann <arnd@arndb.de>; David S. Miller <davem@davemloft.net>;
>Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
>Abeni <pabeni@redhat.com>; Nathan Chancellor <nathan@kernel.org>; Nick
>Desaulniers <ndesaulniers@google.com>; Bill Wendling <morbo@google.com>;
>Justin Stitt <justinstitt@google.com>; Vlad Buslov <vladbu@nvidia.com>; Roi
>Dayan <roid@nvidia.com>; Maor Dickman <maord@nvidia.com>; Gal Pressman
><gal@nvidia.com>; netdev@vger.kernel.org; linux-rdma@vger.kernel.org; linux-
>kernel@vger.kernel.org
>Subject: [PATCH 4/9] mlx5: avoid truncating error message
>
>From: Arnd Bergmann <arnd@arndb.de>
>
>clang warns that one error message is too long for its destination buffer:
>
>drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c:1876:4: error: 'snprintf'
>will always be truncated; specified size is 80, but format string expands to at least
>94 [-Werror,-Wformat-truncation-non-kprintf]
>
>Reword it to be a bit shorter so it always fits.
>
>Fixes: 70f0302b3f20 ("net/mlx5: Bridge, implement mdb offload")
>Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Subbaraya Sundeep <sbhatta@marvell.com>

Thanks,
Sundeep


>---
> drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
>b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
>index 1b9bc32efd6f..c5ea1d1d2b03 100644
>--- a/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
>+++ b/drivers/net/ethernet/mellanox/mlx5/core/esw/bridge.c
>@@ -1874,7 +1874,7 @@ int mlx5_esw_bridge_port_mdb_add(struct net_device
>*dev, u16 vport_num, u16 esw_
> 				 "Failed to lookup bridge port vlan metadata to
>create MDB (MAC=%pM,vid=%u,vport=%u)\n",
> 				 addr, vid, vport_num);
> 			NL_SET_ERR_MSG_FMT_MOD(extack,
>-					       "Failed to lookup bridge port vlan
>metadata to create MDB (MAC=%pM,vid=%u,vport=%u)\n",
>+					       "Failed to lookup vlan metadata for
>MDB (MAC=%pM,vid=%u,vport=%u)\n",
> 					       addr, vid, vport_num);
> 			return -EINVAL;
> 		}
>--
>2.39.2
>

Re: [PATCH 0/9] enabled -Wformat-truncation for clang

[Jakub Kicinski]

On Tue, 26 Mar 2024 23:37:59 +0100 Arnd Bergmann wrote:
> I hope that the patches can get picked up by platform maintainers
> directly, so the final patch can go in later on.

platform == subsystem? :)

Re: [PATCH 0/9] enabled -Wformat-truncation for clang

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 26 Mar 2024 23:37:59 +0100 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> With randconfig build testing, I found only eight files that produce
> warnings with clang when -Wformat-truncation is enabled. This means
> we can just turn it on by default rather than only enabling it for
> "make W=1".
> 
> [...]

Here is the summary with links:
  - [2/9] enetc: avoid truncating error message
    https://git.kernel.org/netdev/net-next/c/9046d581ed58
  - [3/9] qed: avoid truncating work queue length
    https://git.kernel.org/netdev/net-next/c/954fd908f177
  - [4/9] mlx5: avoid truncating error message
    https://git.kernel.org/netdev/net-next/c/b324a960354b

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: (subset) [PATCH 0/9] enabled -Wformat-truncation for clang

[Martin K. Petersen]

On Tue, 26 Mar 2024 23:37:59 +0100, Arnd Bergmann wrote:

> With randconfig build testing, I found only eight files that produce
> warnings with clang when -Wformat-truncation is enabled. This means
> we can just turn it on by default rather than only enabling it for
> "make W=1".
> 
> Unfortunately, gcc produces a lot more warnings when the option
> is enabled, so it's not yet possible to turn it on both both
> compilers.
> 
> [...]

Applied to 6.9/scsi-fixes, thanks!

[7/9] scsi: mylex: fix sysfs buffer lengths
      https://git.kernel.org/mkp/scsi/c/1197c5b2099f

-- 
Martin K. Petersen	Oracle Linux Engineering