# git rev-parse -q --verify daebe06ec4af252eba275f602a08086bc2bca5dc^{commit}
daebe06ec4af252eba275f602a08086bc2bca5dc
already have revision, skipping fetch
# git checkout -q -f -B kisskb daebe06ec4af252eba275f602a08086bc2bca5dc
# git clean -qxdf
# < git log -1
# commit daebe06ec4af252eba275f602a08086bc2bca5dc
# Author: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
# Date:   Wed Apr 25 16:29:31 2018 +0530
# 
#     cpufreq: powernv: Fix the hardlockup by synchronus smp_call in timer interrupt
#     
#     gpstate_timer_handler() uses synchronous smp_call to set the pstate
#     on the requested core. This causes the below hard lockup:
#     
#       smp_call_function_single+0x110/0x180 (unreliable)
#       smp_call_function_any+0x180/0x250
#       gpstate_timer_handler+0x1e8/0x580
#       call_timer_fn+0x50/0x1c0
#       expire_timers+0x138/0x1f0
#       run_timer_softirq+0x1e8/0x270
#       __do_softirq+0x158/0x3e4
#       irq_exit+0xe8/0x120
#       timer_interrupt+0x9c/0xe0
#       decrementer_common+0x114/0x120
#       -- interrupt: 901 at doorbell_global_ipi+0x34/0x50
#       LR = arch_send_call_function_ipi_mask+0x120/0x130
#       arch_send_call_function_ipi_mask+0x4c/0x130
#       smp_call_function_many+0x340/0x450
#       pmdp_invalidate+0x98/0xe0
#       change_huge_pmd+0xe0/0x270
#       change_protection_range+0xb88/0xe40
#       mprotect_fixup+0x140/0x340
#       SyS_mprotect+0x1b4/0x350
#       system_call+0x58/0x6c
#     
#     One way to avoid this is removing the smp-call. We can ensure that the
#     timer always runs on one of the policy-cpus. If the timer gets
#     migrated to a cpu outside the policy then re-queue it back on the
#     policy->cpus. This way we can get rid of the smp-call which was being
#     used to set the pstate on the policy->cpus.
#     
#     Fixes: 7bc54b652f13 ("timers, cpufreq/powernv: Initialize the gpstate timer as pinned")
#     Cc: stable@vger.kernel.org # v4.8+
#     Reported-by: Nicholas Piggin <npiggin@gmail.com>
#     Reported-by: Pridhiviraj Paidipeddi <ppaidipe@linux.vnet.ibm.com>
#     Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
#     Acked-by: Nicholas Piggin <npiggin@gmail.com>
#     Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
#     Acked-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
#     Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
# < /opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux-gcc --version
# < git log --format=%s --max-count=1 daebe06ec4af252eba275f602a08086bc2bca5dc
# < make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc-5.3 CROSS_COMPILE=/opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  pseries_defconfig
# Added to kconfig CONFIG_PPC_POWERNV=n
# yes \n | make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc-5.3 CROSS_COMPILE=/opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  oldconfig
yes: standard output: Broken pipe
yes: write error
# make -s -j 48 ARCH=powerpc O=/kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc-5.3 CROSS_COMPILE=/opt/cross/kisskb/gcc-5.3.0-nolibc/powerpc64-linux/bin/powerpc64-linux-  
Completed OK
# rm -rf /kisskb/build/powerpc-fixes_pseries_defconfig+POWERNV=n_powerpc-5.3
# Build took: 0:02:57.280369