# git rev-parse -q --verify 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71^{commit}
94f0b2d4a1d0c52035aef425da5e022bd2cb1c71
already have revision, skipping fetch
# git checkout -q -f -B kisskb 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71
# git clean -qxdf
# < git log -1
# commit 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71
# Author: Linus Torvalds <torvalds@linux-foundation.org>
# Date:   Tue Jun 15 09:26:19 2021 -0700
# 
#     proc: only require mm_struct for writing
#     
#     Commit 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct") we
#     started using __mem_open() to track the mm_struct at open-time, so that
#     we could then check it for writes.
#     
#     But that also ended up making the permission checks at open time much
#     stricter - and not just for writes, but for reads too.  And that in turn
#     caused a regression for at least Fedora 29, where NIC interfaces fail to
#     start when using NetworkManager.
#     
#     Since only the write side wanted the mm_struct test, ignore any failures
#     by __mem_open() at open time, leaving reads unaffected.  The write()
#     time verification of the mm_struct pointer will then catch the failure
#     case because a NULL pointer will not match a valid 'current->mm'.
#     
#     Link: https://lore.kernel.org/netdev/YMjTlp2FSJYvoyFa@unreal/
#     Fixes: 591a22c14d3f ("proc: Track /proc/$pid/attr/ opener mm_struct")
#     Reported-and-tested-by: Leon Romanovsky <leon@kernel.org>
#     Cc: Kees Cook <keescook@chromium.org>
#     Cc: Christian Brauner <christian.brauner@ubuntu.com>
#     Cc: Andrea Righi <andrea.righi@canonical.com>
#     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
# < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-gcc --version
# < /opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-ld --version
# < git log --format=%s --max-count=1 94f0b2d4a1d0c52035aef425da5e022bd2cb1c71
# < make -s -j 120 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  defconfig
# < make -s -j 120 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  help
# make -s -j 120 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  olddefconfig
# make -s -j 120 ARCH=xtensa O=/kisskb/build/linus_xtensa-defconfig_xtensa CROSS_COMPILE=/opt/cross/kisskb/br-xtensa-full-2016.08-613-ge98b4dd/bin/xtensa-linux-  
Completed OK
# rm -rf /kisskb/build/linus_xtensa-defconfig_xtensa
# Build took: 0:00:21.776362