Re: [PATCH] ext4: avoid -Wformat-security warning

["Arnd Bergmann" <arnd@arndb.de>]

On Thu, Apr 24, 2025, at 13:39, Jan Kara wrote:
> On Wed 23-04-25 18:43:49, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> check_igot_inode() prints a variable string, which causes a harmless
>> warning with 'make W=1':
>> 
>> fs/ext4/inode.c:4763:45: error: format string is not a string literal (potentially insecure) [-Werror,-Wformat-security]
>>  4763 |         ext4_error_inode(inode, function, line, 0, err_str);
>> 
>> Use a trivial "%s" format string instead.
>> 
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> Frankly I don't care much either way but if my memory serves me well year
> or two ago someone was going through the kernel and was replacing pointless
> ("%s", str) cases with printing the string directly. So we should make up
> our minds how we want this... In my opinion this is one of the warnings
> which may be useful but have false positives too often (like here where
> err_str is just a selection from several string literals) so I'm not sure
> it's worth the effort to try to silence it.

I had a look at the git log now and see no evidence of those
patches getting merged, but plenty of patches going the same way
as my patch.

I found one patch that removes a "%s" in the last decade
in favor of directly using a string variable, but it's
part of a larger rework and seems to have been inadvertent
rather than as a directed change:

60a883d119ab ("spi: use kthread_create_worker() helper")

I have patches for all remaining -Wformat-security warnings, in
117 files. I have not tried to split that up and add individual
changelog texts but instead just send patches for regressions
at the moment.

      Arnd

8<---
# full list of files with warnings

arch/x86/kernel/cpu/mce/core.c
arch/x86/kernel/e820.c
arch/x86/xen/smp_pv.c
drivers/accel/habanalabs/common/device.c
drivers/accel/habanalabs/gaudi/gaudi.c
drivers/block/aoe/aoechr.c
drivers/bus/ti-sysc.c
drivers/cdrom/cdrom.c
drivers/char/mem.c
drivers/devfreq/sun8i-a33-mbus.c
drivers/dma-buf/dma-heap.c
drivers/firmware/arm_scmi/notify.c
drivers/firmware/arm_scmi/transports/virtio.c
drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
drivers/gpu/drm/amd/amdkfd/kfd_process.c
drivers/gpu/drm/arm/display/komeda/komeda_event.c
drivers/gpu/drm/etnaviv/etnaviv_gpu.c
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
drivers/gpu/drm/tests/drm_plane_helper_test.c
drivers/gpu/drm/vc4/vc4_crtc.c
drivers/gpu/drm/vmwgfx/vmwgfx_gmrid_manager.c
drivers/i3c/master.c
drivers/iio/adc/aspeed_adc.c
drivers/iio/industrialio-core.c
drivers/iio/trigger/iio-trig-loop.c
drivers/infiniband/core/device.c
drivers/infiniband/hw/hfi1/device.c
drivers/infiniband/hw/hfi1/msix.c
drivers/infiniband/hw/mlx4/mcg.c
drivers/infiniband/hw/qib/qib_file_ops.c
drivers/infiniband/ulp/rtrs/rtrs-clt.c
drivers/input/tablet/aiptek.c
drivers/iommu/arm/arm-smmu/qcom_iommu.c
drivers/iommu/exynos-iommu.c
drivers/iommu/irq_remapping.c
drivers/iommu/mtk_iommu_v1.c
drivers/iommu/omap-iommu.c
drivers/iommu/sprd-iommu.c
drivers/iommu/sun50i-iommu.c
drivers/iommu/tegra-smmu.c
drivers/md/dm-raid.c
drivers/media/dvb-core/dvbdev.c
drivers/media/pci/cx23885/cx23885-dvb.c
drivers/media/pci/netup_unidvb/netup_unidvb_core.c
drivers/media/pci/saa7164/saa7164-dvb.c
drivers/media/pci/smipcie/smipcie-main.c
drivers/media/pci/zoran/zoran_card.c
drivers/media/test-drivers/visl/visl-dec.c
drivers/media/usb/dvb-usb-v2/rtl28xxu.c
drivers/media/usb/dvb-usb/dib0700_devices.c
drivers/media/usb/pvrusb2/pvrusb2-hdw.c
drivers/media/usb/pvrusb2/pvrusb2-std.c
drivers/media/v4l2-core/v4l2-spi.c
drivers/mtd/mtdcore.c
drivers/net/dsa/hirschmann/hellcreek_ptp.c
drivers/net/dsa/sja1105/sja1105_spi.c
drivers/net/ethernet/netronome/nfp/devlink_param.c
drivers/net/ethernet/netronome/nfp/nfp_main.c
drivers/net/ieee802154/adf7242.c
drivers/net/wireless/intel/ipw2x00/libipw_wx.c
drivers/nvme/host/sysfs.c
drivers/of/module.c
drivers/perf/arm_cspmu/arm_cspmu.c
drivers/platform/mellanox/mlxbf-pmc.c
drivers/platform/mellanox/mlxreg-hotplug.c
drivers/platform/mellanox/mlxreg-io.c
drivers/platform/x86/intel/int3472/clk_and_regulator.c
drivers/platform/x86/intel/int3472/discrete.c
drivers/platform/x86/siemens/simatic-ipc.c
drivers/platform/x86/x86-android-tablets/core.c
drivers/pnp/interface.c
drivers/power/supply/ds2760_battery.c
drivers/pwm/core.c
drivers/regulator/da9121-regulator.c
drivers/remoteproc/remoteproc_core.c
drivers/scsi/lpfc/lpfc_scsi.c
drivers/scsi/lpfc/lpfc_sli.c
drivers/scsi/qla2xxx/qla_init.c
drivers/soc/qcom/qcom_aoss.c
drivers/spi/spi-lantiq-ssc.c
drivers/spi/spi.c
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.c
drivers/target/iscsi/iscsi_target_configfs.c
drivers/tty/serial/pch_uart.c
drivers/usb/phy/phy.c
drivers/usb/typec/tcpm/tcpm.c
fs/nfs/nfs42xattr.c
fs/ocfs2/dlm/dlmdomain.c
fs/quota/dquot.c
fs/xfs/xfs_buf_item_recover.c
include/linux/kernel.h
kernel/power/suspend_test.c
kernel/rcu/tree.c
kernel/trace/preemptirq_delay_test.c
kernel/trace/rv/reactor_panic.c
kernel/trace/rv/reactor_printk.c
lib/kunit/string-stream.c
lib/tests/scanf_kunit.c
mm/backing-dev.c
net/core/filter.c
net/rds/transport.c
net/tipc/netlink_compat.c
scripts/Makefile.extrawarn
sound/core/control.c
sound/core/control_led.c
sound/core/seq/seq_clientmgr.c
sound/core/seq/seq_ump_client.c
sound/core/sound.c
sound/drivers/opl3/opl3_seq.c
sound/pci/hda/hda_bind.c
sound/pci/korg1212/korg1212.c
sound/pci/rme32.c
sound/pci/rme96.c
sound/soc/fsl/imx-pcm-rpmsg.c
sound/soc/sof/intel/hda-codec.c
sound/usb/mixer_quirks.c