# git rev-parse -q --verify d4252071b97d2027d246f6a82cbee4d52f618b47^{commit}
d4252071b97d2027d246f6a82cbee4d52f618b47
already have revision, skipping fetch
# git checkout -q -f -B kisskb d4252071b97d2027d246f6a82cbee4d52f618b47
# git clean -qxdf
# < git log -1
# commit d4252071b97d2027d246f6a82cbee4d52f618b47
# Author: Mikulas Patocka <mpatocka@redhat.com>
# Date:   Tue Aug 9 14:32:13 2022 -0400
# 
#     add barriers to buffer_uptodate and set_buffer_uptodate
#     
#     Let's have a look at this piece of code in __bread_slow:
#     
#             get_bh(bh);
#             bh->b_end_io = end_buffer_read_sync;
#             submit_bh(REQ_OP_READ, 0, bh);
#             wait_on_buffer(bh);
#             if (buffer_uptodate(bh))
#                     return bh;
#     
#     Neither wait_on_buffer nor buffer_uptodate contain any memory barrier.
#     Consequently, if someone calls sb_bread and then reads the buffer data,
#     the read of buffer data may be executed before wait_on_buffer(bh) on
#     architectures with weak memory ordering and it may return invalid data.
#     
#     Fix this bug by adding a memory barrier to set_buffer_uptodate and an
#     acquire barrier to buffer_uptodate (in a similar way as
#     folio_test_uptodate and folio_mark_uptodate).
#     
#     Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
#     Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
#     Cc: stable@vger.kernel.org
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 d4252071b97d2027d246f6a82cbee4d52f618b47
# < make -s -j 40 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 defconfig
# < make -s -j 40 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 help
# make -s -j 40 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 olddefconfig
# make -s -j 40 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 
/kisskb/src/arch/um/os-Linux/util.c:17:24: fatal error: sys/random.h: No such file or directory
compilation terminated.
make[2]: *** [/kisskb/src/scripts/Makefile.build:249: arch/um/os-Linux/util.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/kisskb/src/Makefile:1844: arch/um/os-Linux] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:219: __sub-make] Error 2
Command 'make -s -j 40 ARCH=um O=/kisskb/build/linus_um-defconfig_um-x86_64 CROSS_COMPILE=/opt/cross/kisskb/fe-x86-64-core-i7-2017.05/bin/x86_64-linux- SUBARCH=x86_64 ' returned non-zero exit status 2
# rm -rf /kisskb/build/linus_um-defconfig_um-x86_64
# Build took: 0:00:17.952968