On Thu, Oct 06, 2016 at 10:23:05 +0300, Nikolay Shirokovskiy wrote: > > > On 05.10.2016 18:13, Peter Krempa wrote: > > On Mon, Sep 12, 2016 at 17:34:39 +0300, Nikolay Shirokovskiy wrote: > >> Hi, all. > >> > >> In case migration fails due to destination qemu exits unexpectedly user > >> recevies the qemu log in the error message. Unfortunately log is truncated and > >> the most interesting part is missed (below is the example of such a log [1]). > >> > >> Actually for the most cases the first patch will be enough to fix the issue. > >> Originally I thought the problem is qemu logging and reading the log are not in > >> sync (which is true) so I tried to fix it as well in the next patches. > >> > >> * diff from v1: > >> > >> 1. split changes to libvirtd and virtlogd to different patches > >> 2. split virtlogd patch further > >> 3. simplify handling eofs and hangups in draining function > >> > >> [1] log example: > >> > >> CPU Reset (CPU 0) > >> EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000000 > >> ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000 > >> EIP=00000000 EFL=00000000 [-------] CPL=0 II=0 A20=0 SMM=0 HLT=0 > >> ES =0000 00000000 00000000 00000000 > >> CS =0000 00000000 00000000 00000000 > >> SS =0000 00000000 00000000 00000000 > >> DS =0000 00000000 00000000 00000000 > >> FS =0000 00000000 00000000 00000000 > >> GS =0000 00000000 00000000 00000000 > >> LDT=0000 00000000 00000000 00000000 > >> TR =0000 00000000 00000000 00000000 > >> GDT= 00000000 00000000 > >> IDT= 00000000 00000000 > >> CR0=00000000 CR2=00000000 CR3=00000000 CR4=00000000 > >> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 > >> DR6=0000000000000000 DR7=0000000000000000 > >> CCS=00000000 CCD=00000000 CCO=DYNAMIC > >> EFER=0000000000000000 > >> FCW=0000 FSW=0000 [ST=0] FTW=ff MXCSR=00000000 > >> FPR0=0000000000000000 0000 FPR1=0000000000000000 0000 > >> FPR2=0000000000000000 0000 FPR3=0000000000000000 0000 > >> FPR4=0000000000000000 0000 FPR5=0000000000000000 0000 > >> FPR6=0000000000000000 0000 FPR7=0000000000000000 0000 > >> XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000 > >> XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000 > >> XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000 > >> XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000 > >> CPU Reset (CPU 1) > >> EAX=00000000 EBX=00000000 ECX=00000000 EDX=000206a1 > >> ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000 > >> EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0 > >> ES =0000 00000000 0000ffff 00009300 > >> CS =f000 ffff0000 0000ffff 00009b00 > >> SS =0000 00000000 0000ffff 00009300 > >> DS =0000 00000000 0000ffff 00009300 > >> FS =0000 00000000 0000ffff 00009300 > >> GS =0000 00000000 0000ffff 00009300 > >> LDT=0000 00000000 0000ffff 00008200 > >> TR =0000 00000000 0000ffff 00008b00 > >> GDT= 00000000 0000ffff > >> IDT= 00000000 0000ffff > >> CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000 > >> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000 > >> DR6=00000000ffff0ff0 DR7=0000000000000400 > >> CCS=00000000 CCD=00000000 CCO=DYNAMIC > >> EFER=0000000000000000 > >> FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80 > >> FPR0=0000000000000000 0000 FPR1=0000000000000000 0000 > >> FPR2=0000000000000000 0000 FPR3=0000000000000000 0000 > >> FPR4=0000000000000000 0000 FPR5=0000000000000000 0000 > >> FPR6=0000000000000000 0000 FPR7=0000000000000000 0000 > >> XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000 > >> XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000 > >> XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000 > >> XMM06=00000000000000000000000000000000 XMM07=000 > >> qemu: terminating on signal 15 from pid 168133 > > > > I don't think that reporting all of the above is a good idea. We should > > perhaps report at most two last lines. > > > > We already report about half of this, this patch just removes random truncation. > As to most two lines, AFAIU one can not say what part of this log will be > useful for crash investigation. Well, we're talking about error messages. And I doubt anyone would like to see a 50 lines long error message. We have logs for investigating crashes, the user should just get a reasonable message about why QEMU died, i.e., showing something like the last two lines from the log looks like a reasonable thing to do. Jirka -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list