# git rev-parse -q --verify 2f26ed1764b42a8c40d9c48441c73a70d805decf^{commit}
2f26ed1764b42a8c40d9c48441c73a70d805decf
already have revision, skipping fetch
# git checkout -q -f -B kisskb 2f26ed1764b42a8c40d9c48441c73a70d805decf
# git clean -qxdf
# < git log -1
# commit 2f26ed1764b42a8c40d9c48441c73a70d805decf
# Author: Daniel Axtens <dja@axtens.net>
# Date:   Fri May 29 16:14:46 2020 +1000
# 
#     powerpc/64s: Disable sanitisers for C syscall/interrupt entry/exit code
#     
#     syzkaller is picking up a bunch of crashes that look like this:
#     
#       Unrecoverable exception 380 at c00000000037ed60 (msr=8000000000001031)
#       Oops: Unrecoverable exception, sig: 6 [#1]
#       LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
#       Modules linked in:
#       CPU: 0 PID: 874 Comm: syz-executor.0 Not tainted 5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e #0
#       NIP:  c00000000037ed60 LR: c00000000004bac8 CTR: c000000000030990
#       REGS: c0000000555a7230 TRAP: 0380   Not tainted  (5.7.0-rc7-syzkaller-00016-gb0c3ba31be3e)
#       MSR:  8000000000001031 <SF,ME,IR,DR,LE>  CR: 48222882  XER: 20000000
#       CFAR: c00000000004bac4 IRQMASK: 0
#       GPR00: c00000000004bb68 c0000000555a74c0 c0000000024b3500 0000000000000005
#       GPR04: 0000000000000000 0000000000000000 c00000000004bb88 c008000000910000
#       GPR08: 00000000000b0000 c00000000004bac8 0000000000016000 c000000002503500
#       GPR12: c000000000030990 c000000003190000 00000000106a5898 00000000106a0000
#       GPR16: 00000000106a5890 c000000007a92000 c000000008180e00 c000000007a8f700
#       GPR20: c000000007a904b0 0000000010110000 c00000000259d318 5deadbeef0000100
#       GPR24: 5deadbeef0000122 c000000078422700 c000000009ee88b8 c000000078422778
#       GPR28: 0000000000000001 800000000280b033 0000000000000000 c0000000555a75a0
#       NIP [c00000000037ed60] __sanitizer_cov_trace_pc+0x40/0x50
#       LR [c00000000004bac8] interrupt_exit_kernel_prepare+0x118/0x310
#       Call Trace:
#       [c0000000555a74c0] [c00000000004bb68] interrupt_exit_kernel_prepare+0x1b8/0x310 (unreliable)
#       [c0000000555a7530] [c00000000000f9a8] interrupt_return+0x118/0x1c0
#       --- interrupt: 900 at __sanitizer_cov_trace_pc+0x0/0x50
#       ...<random previous call chain>...
#     
#     This is caused by __sanitizer_cov_trace_pc() causing an SLB fault
#     after MSR[RI] has been cleared by __hard_EE_RI_disable(), which we
#     can not recover from.
#     
#     Do not instrument the new syscall/interrupt entry/exit code with KCOV,
#     GCOV or UBSAN.
#     
#     Reported-by: syzbot-ppc64 <ozlabsyz@au1.ibm.com>
#     Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in C")
#     Signed-off-by: Daniel Axtens <dja@axtens.net>
#     Acked-by: Andrew Donnellan <ajd@linux.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /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 2f26ed1764b42a8c40d9c48441c73a70d805decf
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+UP_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  ppc64_defconfig
# Added to kconfig CONFIG_SMP=n
# < make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+UP_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  help
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+UP_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  olddefconfig
# make -s -j 80 ARCH=powerpc O=/kisskb/build/powerpc-fixes_ppc64_defconfig+UP_powerpc-gcc5 CROSS_COMPILE=/opt/cross/kisskb/korg/gcc-5.5.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
/kisskb/src/kernel/trace/ftrace.c: In function 'pid_open':
/kisskb/src/kernel/trace/ftrace.c:7166:6: warning: 'seq_ops' may be used uninitialized in this function [-Wmaybe-uninitialized]
  ret = seq_open(file, seq_ops);
      ^
/kisskb/src/kernel/trace/ftrace.c: In function 'pid_write':
/kisskb/src/kernel/trace/ftrace.c:7244:8: warning: 'filtered_pids' may be used uninitialized in this function [-Wmaybe-uninitialized]
  ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
        ^
/kisskb/src/kernel/trace/ftrace.c:7261:22: warning: 'other_pids' may be used uninitialized in this function [-Wmaybe-uninitialized]
  } else if (pid_list && !other_pids) {
                      ^
WARNING: modpost: vmlinux.o(.text.unlikely+0x2b0): Section mismatch in reference from the function .early_init_mmu() to the function .init.text:.radix__early_init_mmu()
The function .early_init_mmu() references
the function __init .radix__early_init_mmu().
This is often because .early_init_mmu lacks a __init 
annotation or the annotation of .radix__early_init_mmu is wrong.

WARNING: modpost: vmlinux.o(.text.unlikely+0x2bc): Section mismatch in reference from the function .early_init_mmu() to the function .init.text:.hash__early_init_mmu()
The function .early_init_mmu() references
the function __init .hash__early_init_mmu().
This is often because .early_init_mmu lacks a __init 
annotation or the annotation of .hash__early_init_mmu is wrong.

Completed OK
# rm -rf /kisskb/build/powerpc-fixes_ppc64_defconfig+UP_powerpc-gcc5
# Build took: 0:03:22.309527