# 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 <miltonm@us.ibm.com>
# 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 <miltonm@us.ibm.com>
#     Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
#     Link: https://lore.kernel.org/r/20200715233704.1352257-1-anton@ozlabs.org
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-gcc --version
# < /opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-ld --version
# < git log --format=%s --max-count=1 a9f675f950a07d5c1dbcbb97aabac56f5ed085e3
# < make -s -j 24 ARCH=ia64 O=/kisskb/build/powerpc-next_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-  defconfig
# < make -s -j 24 ARCH=ia64 O=/kisskb/build/powerpc-next_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-  help
# make -s -j 24 ARCH=ia64 O=/kisskb/build/powerpc-next_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-  olddefconfig
# make -s -j 24 ARCH=ia64 O=/kisskb/build/powerpc-next_ia64-defconfig_ia64-gcc4.9 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-4.9.4-nolibc/ia64-linux/bin/ia64-linux-  
<stdin>:1511:2: warning: #warning syscall clone3 not implemented [-Wcpp]
In file included from /kisskb/src/arch/ia64/include/uapi/asm/intrinsics.h:22:0,
                 from /kisskb/src/arch/ia64/include/asm/intrinsics.h:11,
                 from /kisskb/src/arch/ia64/include/asm/bitops.h:19,
                 from /kisskb/src/include/linux/bitops.h:29,
                 from /kisskb/src/include/linux/kernel.h:12,
                 from /kisskb/src/include/linux/list.h:9,
                 from /kisskb/src/include/linux/preempt.h:11,
                 from /kisskb/src/include/linux/spinlock.h:51,
                 from /kisskb/src/include/linux/seqlock.h:36,
                 from /kisskb/src/include/linux/time.h:6,
                 from /kisskb/src/fs/nfs/read.c:11:
/kisskb/src/fs/nfs/read.c: In function 'nfs_read_completion':
/kisskb/src/arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value]
 ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
  ^
/kisskb/src/fs/nfs/read.c:196:5: note: in expansion of macro 'xchg'
     xchg(&nfs_req_openctx(req)->error, error);
     ^
/kisskb/src/fs/nfs/read.c: In function 'nfs_readpage':
/kisskb/src/arch/ia64/include/uapi/asm/cmpxchg.h:57:2: warning: value computed is not used [-Wunused-value]
 ((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
  ^
/kisskb/src/fs/nfs/read.c:355:2: note: in expansion of macro 'xchg'
  xchg(&ctx->error, 0);
  ^
No errors detected in 22248 functions.
Completed OK
# rm -rf /kisskb/build/powerpc-next_ia64-defconfig_ia64-gcc4.9
# Build took: 0:02:55.864785