bridge.c:157:11: error: variable 'err' is used uninitialized whenever 'if' condition is false
[Please ignore if it is already reported]
Following build warnings/ errors noticed while building linux mainline master branch with clang-nightly, clang-13, clang-12, clang-11 and clang-10 for arm64 architecture. Whereas gcc-11 build pass.
# to reproduce this build locally: tuxmake --target-arch=arm64 --kconfig=defconfig --toolchain=clang-nightly --wrapper=none --environment=KBUILD_BUILD_TIMESTAMP=@1630870764 --environment=KBUILD_BUILD_USER=tuxmake --environment=KBUILD_BUILD_HOST=tuxmake --runtime=podman --image=855116176053.dkr.ecr.us-east-1.amazonaws.com/tuxmake/arm64_clang-nightly config default kernel xipkernel modules dtbs dtbs-legacy debugkernel headers make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/current ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- HOSTCC=clang CC=clang defconfig make --silent --keep-going --jobs=8 O=/home/tuxbuild/.cache/tuxmake/builds/current ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- HOSTCC=clang CC=clang scripts/dtc/include-prefixes/arm/bcm2711-rpi-4-b.dts:220.10-231.4: Warning (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format error, expected 0,0 scripts/dtc/include-prefixes/arm/bcm2711-rpi-4-b.dts:220.10-231.4: Warning (pci_device_reg): /scb/pcie@7d500000/pci@1,0: PCI unit address format error, expected 0,0 arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi:464.3-52: Warning (pci_device_reg): /pcie@f8000000/pcie@0,0:reg: PCI reg address is not configuration space arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi:464.3-52: Warning (pci_device_reg): /pcie@f8000000/pcie@0,0:reg: PCI reg address is not configuration space arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi:464.3-52: Warning (pci_device_reg): /pcie@f8000000/pcie@0,0:reg: PCI reg address is not configuration space arch/arm64/boot/dts/rockchip/rk3399-gru.dtsi:464.3-52: Warning (pci_device_reg): /pcie@f8000000/pcie@0,0:reg: PCI reg address is not configuration space arch/arm64/kvm/hyp/nvhe/Makefile:58: FORCE prerequisite is missing drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:11: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] else if (mlx5_esw_bridge_dev_same_hw(rep, esw)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:164:9: note: uninitialized use occurs here return err; ^~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:7: note: remove the 'if' if its condition is always true else if (mlx5_esw_bridge_dev_same_hw(rep, esw)) ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:140:9: note: initialize the variable 'err' to silence this warning int err; ^ = 0 drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:262:7: error: variable 'err' is used uninitialized whenever switch case is taken [-Werror,-Wsometimes-uninitialized] case SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS: ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:276:9: note: uninitialized use occurs here return err; ^~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:257:7: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] if (attr->u.brport_flags.mask & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:276:9: note: uninitialized use occurs here return err; ^~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:257:3: note: remove the 'if' if its condition is always true if (attr->u.brport_flags.mask & ~(BR_LEARNING | BR_FLOOD | BR_MCAST_FLOOD)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:247:9: note: initialize the variable 'err' to silence this warning int err; ^ = 0 3 errors generated. make[6]: *** [scripts/Makefile.build:277: drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.o] Error 1 make[6]: Target '__build' not remade because of errors. make[5]: *** [scripts/Makefile.build:540: drivers/net/ethernet/mellanox/mlx5/core] Error 2 make[5]: Target '__build' not remade because of errors. make[4]: *** [scripts/Makefile.build:540: drivers/net/ethernet/mellanox] Error 2 make[4]: Target '__build' not remade because of errors. make[3]: *** [scripts/Makefile.build:540: drivers/net/ethernet] Error 2 make[3]: Target '__build' not remade because of errors. make[2]: *** [scripts/Makefile.build:540: drivers/net] Error 2 make[2]: Target '__build' not remade because of errors. make[1]: *** [Makefile:1872: drivers] Error 2 make[1]: Target '__all' not remade because of errors. make: *** [Makefile:219: __sub-make] Error 2 make: Target '__all' not remade because of errors.
Build config: https://builds.tuxbuild.com/1xjZrnXEZfc3qYzziclNRaugAaN/config
Reported-by: Linux Kernel Functional Testing lkft@linaro.org
meta data: ----------- git_describe: v5.14-9687-g27151f177827 git_repo: https://gitlab.com/Linaro/lkft/mirrors/torvalds/linux-mainline git_sha: 27151f177827d478508e756c7657273261aaf8a9 git_short_log: 27151f177827 (\Merge tag 'perf-tools-for-v5.15-2021-09-04' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux) kconfig: [ defconfig ], kernel_version: 5.14.0 status_message: failure while building tuxmake target(s): default target_arch: arm64 toolchain: clang-nightly, clang-13, clang-12, clang-11 and clang-10
steps to reproduce: https://builds.tuxbuild.com/1xjZrnXEZfc3qYzziclNRaugAaN/tuxmake_reproducer.s...
-- Linaro LKFT https://lkft.linaro.org
On Mon, Sep 6, 2021 at 2:11 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:
drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:11: error: variable 'err' is used uninitialized whenever 'if' condition is false
That compiler warning (now error) seems to be entirely valid.
That's a
if (..) else if (..)
and if neither are valid then the code will return an uninitialized 'err'.
It's possible the two conditionals are guaranteed to cover all cases, but as the compiler says, in that case the "if" in the else clause is pointless and should be removed.
But it does look like 'ret' should probably just be initialized to 0.
Linus
On Mon 06 Sep 2021 at 19:39, Linus Torvalds torvalds@linux-foundation.org wrote:
On Mon, Sep 6, 2021 at 2:11 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:
drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:11: error: variable 'err' is used uninitialized whenever 'if' condition is false
That compiler warning (now error) seems to be entirely valid.
I agree, this is a real issue. It had been reported before and my fix for it was submitted by Saeed last week but wasn't accepted since it was part of larger series that also included features and net-next had already been closed by that time. As far as I understand it is pending submission to net as part of series of bug fixes. Sorry for the delay.
That's a
if (..) else if (..)and if neither are valid then the code will return an uninitialized 'err'.
It's possible the two conditionals are guaranteed to cover all cases, but as the compiler says, in that case the "if" in the else clause is pointless and should be removed.
But it does look like 'ret' should probably just be initialized to 0.
Yep, this if exactly what I did in my patch "net/mlx5: Bridge, fix uninitialized variable usage".
Linus
On Mon, 2021-09-06 at 20:35 +0300, Vlad Buslov wrote:
On Mon 06 Sep 2021 at 19:39, Linus Torvalds torvalds@linux-foundation.org wrote:
On Mon, Sep 6, 2021 at 2:11 AM Naresh Kamboju naresh.kamboju@linaro.org wrote:
drivers/net/ethernet/mellanox/mlx5/core/en/rep/bridge.c:157:11: error: variable 'err' is used uninitialized whenever 'if' condition is false
That compiler warning (now error) seems to be entirely valid.
I agree, this is a real issue. It had been reported before and my fix for it was submitted by Saeed last week but wasn't accepted since it was part of larger series that also included features and net-next had already been closed by that time. As far as I understand it is pending submission to net as part of series of bug fixes. Sorry for the delay.
yes, the fix will be submitted shortly to net/rc branch. due to bad net-next timing the patch couldn't make it to -next.
-
Linus Torvalds -
Naresh Kamboju -
Saeed Mahameed -
Vlad Buslov