Buildresult: gustavoars/versatile_defconfig/arm-gcc4.9 built on Apr 23 2020, 04:58

kisskb

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Status:	OK
Date/Time:	Apr 23 2020, 04:58
Duration:	0:00:45.038039
Builder:	ka2
Revision:	treewide: Replace zero-length array with flexible-array member (`d783301058f3d3605f9ad34f0192692ef572d663)`
Target:	gustavoars/versatile_defconfig/arm-gcc4.9
Branch:	gustavoars
Compiler:	arm-gcc4.9 (arm-linux-gnueabi-gcc (GCC) 4.9.4 / GNU ld (GNU Binutils) 2.29.1.20170915)
Config:	versatile_defconfig (download)
Log:	Download original Possible warnings (3) kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: missing braces around initializer [-Wmissing-braces] drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces] Full Log # git rev-parse -q --verify d783301058f3d3605f9ad34f0192692ef572d663^{commit} d783301058f3d3605f9ad34f0192692ef572d663 already have revision, skipping fetch # git checkout -q -f -B kisskb d783301058f3d3605f9ad34f0192692ef572d663 # git clean -qxdf # < git log -1 # commit d783301058f3d3605f9ad34f0192692ef572d663 # Author: Gustavo A. R. Silva <gustavo@embeddedor.com> # Date: Tue Apr 21 16:19:18 2020 -0500 # # treewide: Replace zero-length array with flexible-array member # # 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-length+array+with+flexible-array+member # [5] https://github.com/GustavoARSilva/linux-hardening/blob/master/cii/kernel-ci/kspp-fam0-20200420.md # # Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-gcc --version # < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi-ld --version # < git log --format=%s --max-count=1 d783301058f3d3605f9ad34f0192692ef572d663 # < make -s -j 48 ARCH=arm O=/kisskb/build/gustavoars_versatile_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- versatile_defconfig # < make -s -j 48 ARCH=arm O=/kisskb/build/gustavoars_versatile_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- help # make -s -j 48 ARCH=arm O=/kisskb/build/gustavoars_versatile_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- olddefconfig # make -s -j 48 ARCH=arm O=/kisskb/build/gustavoars_versatile_defconfig_arm-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/arm-linux-gnueabi/bin/arm-linux-gnueabi- /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/drivers/gpu/drm/drm_dp_mst_topology.c: In function 'drm_dp_mst_dsc_aux_for_port': /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: missing braces around initializer [-Wmissing-braces] struct drm_dp_desc desc = { 0 }; ^ /kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces] Completed OK # rm -rf /kisskb/build/gustavoars_versatile_defconfig_arm-gcc4.9 # Build took: 0:00:45.038039

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