Buildresult: powerpc-fixes/x86_64-allnoconfig/x86_64-gcc4.6 built on Apr 19 2018, 20:09

kisskb

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Status:	OK
Date/Time:	Apr 19 2018, 20:09
Duration:	0:00:11.421728
Builder:	ka4
Revision:	powerpc/kvm: Fix lockups when running KVM guests on Power8 (`56376c5864f8ff4ba7c78a80ae857eee3b1d23d8)`
Target:	powerpc-fixes/x86_64-allnoconfig/x86_64-gcc4.6
Branch:	powerpc-fixes
Compiler:	x86_64-gcc4.6 (x86_64-linux-gcc (GCC) 4.6.3)
Config:	allnoconfig (download)
Log:	Download original Possible warnings (3) kernel/printk/printk.c:183:16: warning: 'old' may be used uninitialized in this function [-Wuninitialized] arch/x86/kernel/apic/io_apic.c:1033:6: warning: 'irq' may be used uninitialized in this function [-Wuninitialized] arch/x86/kernel/e820.c:650:16: warning: 'gapstart' may be used uninitialized in this function [-Wuninitialized] Full Log # git rev-parse -q --verify 56376c5864f8ff4ba7c78a80ae857eee3b1d23d8^{commit} 56376c5864f8ff4ba7c78a80ae857eee3b1d23d8 already have revision, skipping fetch # git checkout -q -f -B kisskb 56376c5864f8ff4ba7c78a80ae857eee3b1d23d8 # git clean -qxdf # < git log -1 # commit 56376c5864f8ff4ba7c78a80ae857eee3b1d23d8 # Author: Michael Ellerman <mpe@ellerman.id.au> # Date: Thu Apr 19 16:22:20 2018 +1000 # # powerpc/kvm: Fix lockups when running KVM guests on Power8 # # When running KVM guests on Power8 we can see a lockup where one CPU # stops responding. This often leads to a message such as: # # watchdog: CPU 136 detected hard LOCKUP on other CPUs 72 # Task dump for CPU 72: # qemu-system-ppc R running task 10560 20917 20908 0x00040004 # # And then backtraces on other CPUs, such as: # # Task dump for CPU 48: # ksmd R running task 10032 1519 2 0x00000804 # Call Trace: # ... # --- interrupt: 901 at smp_call_function_many+0x3c8/0x460 # LR = smp_call_function_many+0x37c/0x460 # pmdp_invalidate+0x100/0x1b0 # __split_huge_pmd+0x52c/0xdb0 # try_to_unmap_one+0x764/0x8b0 # rmap_walk_anon+0x15c/0x370 # try_to_unmap+0xb4/0x170 # split_huge_page_to_list+0x148/0xa30 # try_to_merge_one_page+0xc8/0x990 # try_to_merge_with_ksm_page+0x74/0xf0 # ksm_scan_thread+0x10ec/0x1ac0 # kthread+0x160/0x1a0 # ret_from_kernel_thread+0x5c/0x78 # # This is caused by commit 8c1c7fb0b5ec ("powerpc/64s/idle: avoid sync # for KVM state when waking from idle"), which added a check in # pnv_powersave_wakeup() to see if the kvm_hstate.hwthread_state is # already set to KVM_HWTHREAD_IN_KERNEL, and if so to skip the store and # test of kvm_hstate.hwthread_req. # # The problem is that the primary does not set KVM_HWTHREAD_IN_KVM when # entering the guest, so it can then come out to cede with # KVM_HWTHREAD_IN_KERNEL set. It can then go idle in kvm_do_nap after # setting hwthread_req to 1, but because hwthread_state is still # KVM_HWTHREAD_IN_KERNEL we will skip the test of hwthread_req when we # wake up from idle and won't go to kvm_start_guest. From there the # thread will return somewhere garbage and crash. # # Fix it by skipping the store of hwthread_state, but not the test of # hwthread_req, when coming out of idle. It's OK to skip the sync in # that case because hwthread_req will have been set on the same thread, # so there is no synchronisation required. # # Fixes: 8c1c7fb0b5ec ("powerpc/64s/idle: avoid sync for KVM state when waking from idle") # 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 56376c5864f8ff4ba7c78a80ae857eee3b1d23d8 # < 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: 0:00:11.421728

© Michael Ellerman 2006-2018.