# git rev-parse -q --verify f45c105149f3ea8f1d96d43fe45b7fba65535077^{commit}
f45c105149f3ea8f1d96d43fe45b7fba65535077
already have revision, skipping fetch
# git checkout -q -f -B kisskb f45c105149f3ea8f1d96d43fe45b7fba65535077
# git clean -qxdf
# < git log -1
# commit f45c105149f3ea8f1d96d43fe45b7fba65535077
# Author: Gustavo A. R. Silva <gustavo@embeddedor.com>
# Date:   Fri Apr 24 09:07:40 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/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-ld --version
# < git log --format=%s --max-count=1 f45c105149f3ea8f1d96d43fe45b7fba65535077
# < make -s -j 48 ARCH=ia64 O=/kisskb/build/gustavoars_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  defconfig
# < make -s -j 48 ARCH=ia64 O=/kisskb/build/gustavoars_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  help
# make -s -j 48 ARCH=ia64 O=/kisskb/build/gustavoars_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  olddefconfig
# make -s -j 48 ARCH=ia64 O=/kisskb/build/gustavoars_ia64-defconfig_ia64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/ia64-linux/bin/ia64-linux-  
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:204:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:72:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:471:21: note: 'pdeo' was declared here
/kisskb/src/mm/vmstat.c: In function 'sysctl_vm_numa_stat_handler':
/kisskb/src/mm/vmstat.c:90:5: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/futex.c: In function 'do_futex':
/kisskb/src/kernel/futex.c:1676:3: warning: 'oldval' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/futex.c:1652:6: note: 'oldval' was declared here
/kisskb/src/fs/ext4/extents.c: In function 'ext4_convert_unwritten_io_end_vec':
/kisskb/src/fs/ext4/extents.c:4774:23: warning: 'ret' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1774:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/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]
/kisskb/src/drivers/gpu/drm/drm_dp_mst_topology.c:5497:9: warning: (near initialization for 'desc.ident') [-Wmissing-braces]
/kisskb/src/fs/nfs/read.c: In function 'nfs_read_completion':
/kisskb/src/fs/nfs/read.c:196:5: warning: value computed is not used [-Wunused-value]
/kisskb/src/fs/nfs/read.c: In function 'nfs_readpage':
/kisskb/src/fs/nfs/read.c:353:2: warning: value computed is not used [-Wunused-value]
/kisskb/src/fs/nfsd/nfs4xdr.c: In function 'nfsd4_encode_components_esc':
/kisskb/src/fs/nfsd/nfs4xdr.c:2151:9: warning: 'str' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c: In function 'handle_dots':
/kisskb/src/fs/namei.c:1805:10: warning: 'inode' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/namei.c:1805:10: warning: 'seq' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/udf/unicode.c: In function 'udf_name_conv_char':
/kisskb/src/fs/udf/unicode.c:132:8: warning: 'c' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/usb/core/devio.c: In function 'async_completed':
/kisskb/src/drivers/usb/core/devio.c:625:23: warning: 'errno' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/io_uring.c: In function '__io_sqe_files_update':
/kisskb/src/fs/io_uring.c:6701:13: warning: 'err' may be used uninitialized in this function [-Wuninitialized]
No errors detected in 22345 functions.
Completed OK
# rm -rf /kisskb/build/gustavoars_ia64-defconfig_ia64-gcc4.6
# Build took: 0:01:57.756911