# git rev-parse -q --verify a75a001540d03c30315e43884ad95cc68040f18d^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test
error: The last gc run reported the following. Please correct the root cause
and remove .git/gc.log.
Automatic cleanup will not be performed until the file is removed.

warning: There are too many unreachable loose objects; run 'git prune' to remove them.

# git rev-parse -q --verify a75a001540d03c30315e43884ad95cc68040f18d^{commit}
a75a001540d03c30315e43884ad95cc68040f18d
# git checkout -q -f -B kisskb a75a001540d03c30315e43884ad95cc68040f18d
# git clean -qxdf
# < git log -1
# commit a75a001540d03c30315e43884ad95cc68040f18d
# Author: Michael Ellerman <mpe@ellerman.id.au>
# Date:   Thu Nov 1 16:21:05 2018 +1100
# 
#     powerpc/mm/64s: Fix preempt warning in slb_allocate_kernel()
#     
#     With preempt enabled we see warnings in do_slb_fault():
#     
#       BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u33:0/98
#       futex hash table entries: 4096 (order: 3, 524288 bytes)
#       caller is do_slb_fault+0x204/0x230
#       CPU: 5 PID: 98 Comm: kworker/u33:0 Not tainted 4.19.0-rc3-gcc-7.3.1-00022-g1936f094e164 #138
#       Call Trace:
#         dump_stack+0xb4/0x104 (unreliable)
#         check_preemption_disabled+0x148/0x150
#         do_slb_fault+0x204/0x230
#         data_access_slb_common+0x138/0x180
#     
#     This is caused by the get_paca() in slb_allocate_kernel(), which
#     includes a call to debug_smp_processor_id().
#     
#     slb_allocate_kernel() can only be called from do_slb_fault(), and in
#     that path interrupts are hard disabled and so we can't be preempted,
#     but we can't update the preempt flags (in thread_info) because that
#     could cause an SLB fault.
#     
#     So just use local_paca which is safe and doesn't cause the warning.
#     
#     Fixes: 48e7b7695745 ("powerpc/64s/hash: Convert SLB miss handlers to C")
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-gcc --version
# < git log --format=%s --max-count=1 a75a001540d03c30315e43884ad95cc68040f18d
# < make -s -j 10 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-  defconfig
# make -s -j 10 ARCH=s390 O=/kisskb/build/powerpc-fixes_s390-defconfig_s390x CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/s390x-linux/bin/s390x-linux-  
/kisskb/src/kernel/cgroup/cgroup-v1.c: In function 'cgroup1_mount':
/kisskb/src/kernel/cgroup/cgroup-v1.c:1256:20: warning: 'root' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:186:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c: In function 'proc_reg_open':
/kisskb/src/include/linux/list.h:65:12: warning: 'pdeo' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/fs/proc/inode.c:341:21: note: 'pdeo' was declared here
/kisskb/src/mm/hugetlb.c: In function 'alloc_pool_huge_page':
/kisskb/src/mm/hugetlb.c:1433:5: warning: 'page' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/net/tun.c: In function 'tun_get_user':
/kisskb/src/drivers/net/tun.c:1819:30: warning: 'copylen' may be used uninitialized in this function [-Wuninitialized]
/kisskb/src/drivers/net/tun.c:1729:46: warning: 'linear' may be used uninitialized in this function [-Wuninitialized]
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_s390-defconfig_s390x
# Build took: 0:02:41.457388