# git rev-parse -q --verify a9f675f950a07d5c1dbcbb97aabac56f5ed085e3^{commit} a9f675f950a07d5c1dbcbb97aabac56f5ed085e3 already have revision, skipping fetch # git checkout -q -f -B kisskb a9f675f950a07d5c1dbcbb97aabac56f5ed085e3 # git clean -qxdf # < git log -1 # commit a9f675f950a07d5c1dbcbb97aabac56f5ed085e3 # Author: Milton Miller # Date: Thu Jul 16 09:37:04 2020 +1000 # # powerpc/vdso: Fix vdso cpu truncation # # The code in vdso_cpu_init that exposes the cpu and numa node to # userspace via SPRG_VDSO incorrctly masks the cpu to 12 bits. This means # that any kernel running on a box with more than 4096 threads (NR_CPUS # advertises a limit of of 8192 cpus) would expose userspace to two cpu # contexts running at the same time with the same cpu number. # # Note: I'm not aware of any distro shipping a kernel with support for more # than 4096 threads today, nor of any system image that currently exceeds # 4096 threads. Found via code browsing. # # Fixes: 18ad51dd342a7eb09dbcd059d0b451b616d4dafc ("powerpc: Add VDSO version of getcpu") # Signed-off-by: Milton Miller # Signed-off-by: Anton Blanchard # Signed-off-by: Michael Ellerman # Link: https://lore.kernel.org/r/20200715233704.1352257-1-anton@ozlabs.org # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version # < /opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-ld --version # < git log --format=%s --max-count=1 a9f675f950a07d5c1dbcbb97aabac56f5ed085e3 # < make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_pseries_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- pseries_defconfig # < make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_pseries_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- help # make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_pseries_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- olddefconfig # make -s -j 8 ARCH=powerpc O=/kisskb/build/powerpc-next_pseries_defconfig_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux- Completed OK # rm -rf /kisskb/build/powerpc-next_pseries_defconfig_powerpc-gcc5 # Build took: 0:06:32.333517