(In reply to Maxim Bakulin from comment #492) > Created attachment 280669 [details] > dmesg of freeze with 4.20.3 kernel and nomwait, rcu_nocbs, max_cstate applied > > some older info here: > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1690085/comments/566 > > I have three machines with new 2700x CPUs, and all three of them experience > freezes in xubuntu 18.04 after some time of work. I use compiling QEMU with > make -j16 in a loop to test for stability. > > I'm not sure it is the same bug, because I observe different behaviour: one > machine, that was compiling QEMU, froze during the night, and the one left > idle worked for 1 day. Another thing that SEEM to help is disabling SMT:
The Processor errata lists two bugs (SMT-related) for Ryzen 1 and Ryzen 2 (1095 and 1109) with status "no fix planned". If you disable MWAIT but enable SMT, you are left with bug 1095: "Potential Violation of Read Ordering In Lock Operation In SMT (Simultaneous Multithreading) Mode". This can cause crashes. Not necessarily the cause of your crashes :-D # lsmsr -r 0xc0011020 warning: unknown MSR c0011020 unknown = 0x0006800000000010 On my Ryzen 1600X bit 57 (no idea what it does) is 0. (But I have nosmt=force.) Linux kernel doesn't seem to touch that bit. Also, if you get "ACPI MWAIT C-state 0x0 not supported by HW (0x0)", mwait is not used by kernel. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1690085 Title: Ryzen 1800X freeze - rcu_sched detected stalls on CPUs/tasks To manage notifications about this bug go to: https://bugs.launchpad.net/linux/+bug/1690085/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
