# git rev-parse -q --verify d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test
# git rev-parse -q --verify d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb^{commit}
d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb
# git checkout -q -f -B kisskb d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb
# git clean -qxdf
# < git log -1
# commit d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb
# Author: Andrew Donnellan <ajd@linux.ibm.com>
# Date:   Tue Dec 10 00:22:21 2019 +1100
# 
#     powerpc: Fix __clear_user() with KUAP enabled
#     
#     The KUAP implementation adds calls in clear_user() to enable and disable
#     access to userspace memory. However, it doesn't add these to
#     __clear_user(), which is used in the ptrace regset code.
#     
#     As there's only one direct user of __clear_user(), and the time taken to
#     set the AMR for KUAP purposes is going to dominate the cost of a quick
#     access_ok(), there's not much point having a separate path.
#     
#     Rename __clear_user() to clear_user_asm(), and make __clear_user() just
#     call clear_user().
#     
#     Reported-by: syzbot+f25ecf4b2982d8c7a640@syzkaller-ppc64.appspotmail.com
#     Reported-by: Daniel Axtens <dja@axtens.net>
#     Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
#     Fixes: de78a9c42a79 ("powerpc: Add a framework for Kernel Userspace Access Protection")
#     Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20191209132221.15328-1-ajd@linux.ibm.com
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-ld --version
# < git log --format=%s --max-count=1 d04cb29a7ef9e90cb0e4f16953f2d7484a9a48fb
# < make -s -j 80 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  allnoconfig
# make -s -j 80 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64-gcc4.6 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  
/kisskb/src/tools/objtool
/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/arch/x86/kernel/apic/io_apic.c: In function 'mp_map_pin_to_irq':
/kisskb/src/arch/x86/kernel/apic/io_apic.c:1037:6: warning: 'irq' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/arch/x86/kernel/e820.c: In function 'e820__setup_pci_gap':
/kisskb/src/arch/x86/kernel/e820.c:665:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized]
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64-gcc4.6
# Build took: 0:00:18.579432