# git rev-parse -q --verify 27284084ced264c4f7a6e894b6b77b13185e0400^{commit} 27284084ced264c4f7a6e894b6b77b13185e0400 already have revision, skipping fetch # git checkout -q -f -B kisskb 27284084ced264c4f7a6e894b6b77b13185e0400 # git clean -qxdf # < git log -1 # commit 27284084ced264c4f7a6e894b6b77b13185e0400 # Author: Gustavo A. R. Silva # Date: Thu May 28 09:35:11 2020 -0500 # # treewide: Replace zero-length array with flexible-array # # The current codebase makes use of the zero-length array language # extension to the C90 standard, but the preferred mechanism to declare # variable-length types such as these ones is a flexible array member[1][2], # introduced in C99: # # struct foo { # int stuff; # struct boo array[]; # }; # # By making use of the mechanism above, we will get a compiler warning # in case the flexible array does not occur last in the structure, which # will help us prevent some kind of undefined behavior bugs from being # inadvertently introduced[3] to the codebase from now on. # # Also, notice that, dynamic memory allocations won't be affected by # this change: # # "Flexible array members have incomplete type, and so the sizeof operator # may not be applied. As a quirk of the original implementation of # zero-length arrays, sizeof evaluates to zero."[1] # # sizeof(flexible-array-member) triggers a warning because flexible array # members have incomplete type[1]. There are some instances of code in # which the sizeof operator is being incorrectly/erroneously applied to # zero-length arrays and the result is zero. Such instances may be hiding # some bugs. So, this work (flexible-array member conversions) will also # help to get completely rid of those sorts of issues. # # Notice that, currently, more than 250 of these patches have already # been merged into mainline during the last merge window, including # 5.7-rc2. So, in order to make better use of everyone's time, I'm # planning to add this treewide patch to my -next tree and then send a # pull request to Linus for 5.7-rc3 or -rc4, after getting some acks # and/or reviews. # # This treewide patch has been successfully built (on top of v5.7-rc1) for # multiple architectures (arm, arm64, sparc, powerpc, ia64, s390, i386, # nios2, c6x, xtensa, openrisc, mips, parisc, x86_64, riscv, sh, sparc64) # and 82 different configurations with the help of the 0-day CI guys[5]. # # This issue was found with the help of Coccinelle. # # [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html # [2] https://github.com/KSPP/linux/issues/21 # [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") # [4] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/?qt=grep&q=replace+zero-leng # # Signed-off-by: Gustavo A. R. Silva # < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-gcc --version # < /opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux-ld --version # < git log --format=%s --max-count=1 27284084ced264c4f7a6e894b6b77b13185e0400 # < make -s -j 48 ARCH=arm64 O=/kisskb/build/gustavoars_arm64-allmodconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- allmodconfig # < make -s -j 48 ARCH=arm64 O=/kisskb/build/gustavoars_arm64-allmodconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- help # make -s -j 48 ARCH=arm64 O=/kisskb/build/gustavoars_arm64-allmodconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- olddefconfig # make -s -j 48 ARCH=arm64 O=/kisskb/build/gustavoars_arm64-allmodconfig_arm64-gcc5.4 CROSS_COMPILE=/opt/cross/kisskb/br-aarch64-glibc-2016.08-613-ge98b4dd/bin/aarch64-linux- arch/arm64/Makefile:27: ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum arch/arm64/Makefile:35: LSE atomics not supported by binutils /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi:1086.4-52: Warning (dma_ranges_format): /soc/dram-controller@1c62000:dma-ranges: "dma-ranges" property has invalid length (12 bytes) (parent #address-cells == 1, child #address-cells == 2, #size-cells == 1) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #address-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #size-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/qcom/ipq6018.dtsi:127.3-14: Warning (dma_ranges_format): /soc:dma-ranges: empty "dma-ranges" property but its #address-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/qcom/ipq6018.dtsi:127.3-14: Warning (dma_ranges_format): /soc:dma-ranges: empty "dma-ranges" property but its #size-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #address-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #size-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #address-cells (1) differs from / (2) /kisskb/src/arch/arm64/boot/dts/broadcom/stingray/stingray-usb.dtsi:7.3-14: Warning (dma_ranges_format): /usb:dma-ranges: empty "dma-ranges" property but its #size-cells (1) differs from / (2) /kisskb/src/scripts/dtc/include-prefixes/arm/bcm2835-rpi.dtsi:18.4-15: Warning (dma_ranges_format): /soc/firmware:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /soc (1) /kisskb/src/scripts/dtc/include-prefixes/arm/bcm2835-rpi.dtsi:18.4-15: Warning (dma_ranges_format): /soc/firmware:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /soc (1) /kisskb/src/scripts/dtc/include-prefixes/arm/bcm2835-rpi.dtsi:18.4-15: Warning (dma_ranges_format): /soc/firmware:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /soc (1) /kisskb/src/scripts/dtc/include-prefixes/arm/bcm2835-rpi.dtsi:18.4-15: Warning (dma_ranges_format): /soc/firmware:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /soc (1) /kisskb/src/scripts/dtc/include-prefixes/arm/bcm2835-rpi.dtsi:18.4-15: Warning (dma_ranges_format): /soc/firmware:dma-ranges: empty "dma-ranges" property but its #address-cells (2) differs from /soc (1) /kisskb/src/drivers/gpu/drm/bridge/tc358768.c: In function 'tc358768_bridge_pre_enable': /kisskb/src/drivers/gpu/drm/bridge/tc358768.c:840:1: warning: the frame size of 2224 bytes is larger than 2048 bytes [-Wframe-larger-than=] } ^ In file included from /kisskb/src/include/linux/rwsem.h:16:0, from /kisskb/src/include/linux/notifier.h:15, from /kisskb/src/include/linux/clk.h:14, from /kisskb/src/drivers/tty/serial/sh-sci.c:20: /kisskb/src/drivers/tty/serial/sh-sci.c: In function 'sci_dma_rx_submit': /kisskb/src/include/linux/spinlock.h:289:3: warning: 'flags' may be used uninitialized in this function [-Wmaybe-uninitialized] _raw_spin_unlock_irqrestore(lock, flags); \ ^ /kisskb/src/drivers/tty/serial/sh-sci.c:1348:16: note: 'flags' was declared here unsigned long flags; ^ /kisskb/src/kernel/futex.c: In function 'do_futex': /kisskb/src/kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] return oldval == cmparg; ^ /kisskb/src/kernel/futex.c:1652:6: note: 'oldval' was declared here int oldval, ret; ^ /kisskb/src/net/mptcp/protocol.c: In function 'mptcp_sendmsg_frag': /kisskb/src/net/mptcp/protocol.c:606:6: warning: 'dfrag_collapsed' may be used uninitialized in this function [-Wmaybe-uninitialized] if (!dfrag_collapsed) { ^ /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c: In function 'sh_mobile_i2c_isr': /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:396:26: warning: 'data' may be used uninitialized in this function [-Wmaybe-uninitialized] pd->msg->buf[real_pos] = data; ^ /kisskb/src/drivers/i2c/busses/i2c-sh_mobile.c:369:16: note: 'data' was declared here unsigned char data; ^ Completed OK # rm -rf /kisskb/build/gustavoars_arm64-allmodconfig_arm64-gcc5.4 # Build took: 0:19:36.889371