On Mon, Oct 07, 2013 at 10:55:33AM +0200, Peter Zijlstra wrote: > On Sun, Oct 06, 2013 at 07:44:30AM +0800, Fengguang Wu wrote: > > Greetings, > > > > I got the below dmesg and the first bad commit is > > > > commit 0c44c2d0f459cd7e275242b72f500137c4fa834d > > Author: Peter Zijlstra <pet...@infradead.org> > > Date: Wed Sep 11 15:19:24 2013 +0200 > > > > x86: Use asm goto to implement better modify_and_test() functions > > > > Linus suggested using asm goto to get rid of the typical SETcc + TEST > > instruction pair -- which also clobbers an extra register -- for our > > typical modify_and_test() functions. > > > > Because asm goto doesn't allow output fields it has to include an > > unconditinal memory clobber when it changes a memory variable to force > > a reload. > > > > Luckily all atomic ops already imply a compiler barrier to go along > > with their memory barrier semantics. > > > > Suggested-by: Linus Torvalds <torva...@linux-foundation.org> > > Signed-off-by: Peter Zijlstra <pet...@infradead.org> > > Link: > > http://lkml.kernel.org/n/tip-0mtn9siwbeo1d33bap142...@git.kernel.org > > Signed-off-by: Ingo Molnar <mi...@kernel.org> > > > Well that blows,.. Anybody got any clue as to where to start looking? > I've not actually seen anything like this on my own machines.
Perhaps it's related to one of - the randconfig - kvm - gcc In the end of dmesg file, there is the qemu command line to run the kernel: qemu-system-x86_64 -cpu kvm64 -enable-kvm -kernel /kernel/i386-randconfig-j1-10052106/a0cf1abc25ac197dd97b857c0f6341066a8cb1cf/vmlinuz-3.12.0-rc2-next-20130927-03100-ga0cf1ab -append 'hung_task_panic=1 rcutree.rcu_cpu_stall_timeout=100 log_buf_len=8M ignore_loglevel debug sched_debug apic=debug dynamic_printk sysrq_always_enabled panic=10 prompt_ramdisk=0 console=ttyS0,115200 console=tty0 vga=normal root=/dev/ram0 rw link=/kernel-tests/run-queue/kvm/i386-randconfig-j1-10052106/next:master/.vmlinuz-a0cf1abc25ac197dd97b857c0f6341066a8cb1cf-20131005211923-7-athens branch=next/master BOOT_IMAGE=/kernel/i386-randconfig-j1-10052106/a0cf1abc25ac197dd97b857c0f6341066a8cb1cf/vmlinuz-3.12.0-rc2-next-20130927-03100-ga0cf1ab' -initrd /kernel-tests/initrd/quantal-core-i386.cgz -m 256M -smp 2 -net nic,vlan=0,macaddr=00:00:00:00:00:00,model=virtio -net user,vlan=0,hostfwd=tcp::10661-:22 -net nic,vlan=1,model=e1000 -net user,vlan=1 -boot order=nc -no-reboot -watchdog i6300esb -drive file=/fs/LABEL=KVM/disk0-quantal-athens-6,media=disk,if=virtio -drive file=/fs/LABEL=KVM/disk1-quantal-athens-6,media=disk,if=virtio -drive file=/fs/LABEL=KVM/disk2-quantal-athens-6,media=disk,if=virtio -drive file=/fs/LABEL=KVM/disk3-quantal-athens-6,media=disk,if=virtio -drive file=/fs/LABEL=KVM/disk4-quantal-athens-6,media=disk,if=virtio -drive file=/fs/LABEL=KVM/disk5-quantal-athens-6,media=disk,if=virtio -pidfile /dev/shm/kboot/pid-quantal-athens-6 -serial file:/dev/shm/kboot/serial-quantal-athens-6 -daemonize -display none -monitor null > Wu, do you use the same compiler version for all the builds that crash > like this (I'm assuming the other email was this same commit)? Does a > different compiler make things work again? Good point. I'll try a different compiler. Thanks, Fengguang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
