# git rev-parse -q --verify ac61c1156623455c46701654abd8c99720bceea1^{commit}
# git fetch -q -n -f git://gitlab.ozlabs.ibm.com/linuxppc/linux.git fixes-test
# git rev-parse -q --verify ac61c1156623455c46701654abd8c99720bceea1^{commit}
ac61c1156623455c46701654abd8c99720bceea1
# git checkout -q -f -B kisskb ac61c1156623455c46701654abd8c99720bceea1
# git clean -qxdf
# < git log -1
# commit ac61c1156623455c46701654abd8c99720bceea1
# Author: Nicholas Piggin <npiggin@gmail.com>
# Date:   Wed Apr 25 12:17:53 2018 +1000
# 
#     powerpc: Fix smp_send_stop NMI IPI handling
#     
#     The NMI IPI handler for a receiving CPU increments nmi_ipi_busy_count
#     over the handler function call, which causes later smp_send_nmi_ipi()
#     callers to spin until the call is finished.
#     
#     The stop_this_cpu() function never returns, so the busy count is never
#     decremeted, which can cause the system to hang in some cases. For
#     example panic() will call smp_send_stop() early on which calls
#     stop_this_cpu() on other CPUs, then later in the reboot path,
#     pnv_restart() will call smp_send_stop() again, which hangs.
#     
#     Fix this by adding a special case to the stop_this_cpu() handler to
#     decrement the busy count, because it will never return.
#     
#     Now that the NMI/non-NMI versions of stop_this_cpu() are different,
#     split them out into separate functions rather than doing #ifdef tricks
#     to share the body between the two functions.
#     
#     Fixes: 6bed3237624e3 ("powerpc: use NMI IPI for smp_send_stop")
#     Reported-by: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
#     Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
#     [mpe: Split out the functions, tweak change log a bit]
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-gcc --version
# < git log --format=%s --max-count=1 ac61c1156623455c46701654abd8c99720bceea1
# < make -s -j 40 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  allnoconfig
# make -s -j 40 ARCH=x86_64 O=/kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64 CROSS_COMPILE=/opt/cross/kisskb/gcc-4.6.3-nolibc/x86_64-linux/bin/x86_64-linux-  
/kisskb/src/kernel/printk/printk.c: In function 'devkmsg_sysctl_set_loglvl':
/kisskb/src/kernel/printk/printk.c:183:16: 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:1033:6: 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:650:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized]
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_x86_64-allnoconfig_x86_64
# Build took: 0:00:14.484316