# git rev-parse -q --verify 63045bfd3c8dbe9c8bee7e33291202725154cb2c^{commit}
# git fetch -q -n -f git://fs.ozlabs.ibm.com/kernel/linus master
# git rev-parse -q --verify 63045bfd3c8dbe9c8bee7e33291202725154cb2c^{commit}
63045bfd3c8dbe9c8bee7e33291202725154cb2c
# git checkout -q -f -B kisskb 63045bfd3c8dbe9c8bee7e33291202725154cb2c
# git clean -qxdf
# < git log -1
# commit 63045bfd3c8dbe9c8bee7e33291202725154cb2c
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Mon Jan 10 19:33:36 2022 -0800
# 
#     netfilter: nf_tables: don't use 'data_size' uninitialized
#     
#     Commit 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout") never
#     initialized the new 'data_size' variable.
#     
#     I'm not sure how it ever worked, but it might have worked almost by
#     accident - gcc seems to occasionally miss these kinds of 'variable used
#     uninitialized' situations, but I've seen it do so because it ended up
#     zero-initializing them due to some other simplification.
#     
#     But clang is very unhappy about it all, and correctly reports
#     
#         net/netfilter/nf_tables_api.c:8278:4: error: variable 'data_size' is uninitialized when used here [-Werror,-Wuninitialized]
#                                 data_size += sizeof(*prule) + rule->dlen;
#                                 ^~~~~~~~~
#         net/netfilter/nf_tables_api.c:8263:30: note: initialize the variable 'data_size' to silence this warning
#                 unsigned int size, data_size;
#                                             ^
#                                              = 0
#         1 error generated.
#     
#     and this fix just initializes 'data_size' to zero before the loop.
#     
#     Fixes: 2c865a8a28a1 ("netfilter: nf_tables: add rule blob layout")
#     Cc: Pablo Neira Ayuso <pablo@netfilter.org>
#     Cc: Jakub Kicinski <kuba@kernel.org>
#     Cc: David Miller <davem@davemloft.net>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-ld --version
# < git log --format=%s --max-count=1 63045bfd3c8dbe9c8bee7e33291202725154cb2c
# < make -s -j 24 ARCH=arm64 O=/kisskb/build/linus-rand_arm64-randconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-  randconfig
# Added to kconfig CONFIG_PREVENT_FIRMWARE_BUILD=y
# < make -s -j 24 ARCH=arm64 O=/kisskb/build/linus-rand_arm64-randconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-  help
# make -s -j 24 ARCH=arm64 O=/kisskb/build/linus-rand_arm64-randconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-  olddefconfig
.config:6588:warning: override: reassigning to symbol PREVENT_FIRMWARE_BUILD
# make -s -j 24 ARCH=arm64 O=/kisskb/build/linus-rand_arm64-randconfig_arm64-gcc8 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-8.1.0-nolibc/aarch64-linux/bin/aarch64-linux-  
Completed OK
# rm -rf /kisskb/build/linus-rand_arm64-randconfig_arm64-gcc8
# Build took: 0:11:11.521820