Created attachment 381067 [details] FC12 traces when processes hang Description of problem: I am running an x86_64 FC12 domU PV machine under x86_64 xen host. Kernel Version is 2.6.31.9-174.fc12.x86_64. Under heavy disk I/O (the system runs koji build environment), the kernel hangs, sometimes forever (responds to ping, but no activity can be done), other times only some processes hangs. In all cases a lot of processes results into "being blocked for more than 120 seconds). Sometimes is httpd, more frequently is pdflush, kswapd and kjournald. The only cure is to hard reset the vm. Initially I was suspecting filesystem issues, so move from ext4 to ext3, but the result is the same. The domU is running over disk images (xvd block device) not on a phys device. If the machine is converted to HVM, no more issues (but is slooow). Attached kernel call traces when system hangs. Version-Release number of selected component (if applicable): domU is FC12 PV VM with kernel 2.6.31.9-174.fc12.x86_64 domO kernel version is : 2.6.18-164.9.1.el5xen dom0 (xen host) is Centos 5.4 with latest centos xen: [root@xen2 images]# xm info host : xen2 release : 2.6.18-164.9.1.el5xen version : #1 SMP Tue Dec 15 21:31:37 EST 2009 machine : x86_64 nr_cpus : 8 nr_nodes : 1 sockets_per_node : 2 cores_per_socket : 4 threads_per_core : 1 cpu_mhz : 2333 hw_caps : bfebfbff:20000800:00000000:00000140:0004e3bd:00000000:00000001 total_memory : 8189 free_memory : 38 node_to_cpu : node0:0-7 xen_major : 3 xen_minor : 1 xen_extra : .2-164.9.1.el5 xen_caps : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64 xen_pagesize : 4096 platform_params : virt_start=0xffff800000000000 xen_changeset : unavailable cc_compiler : gcc version 4.1.2 20080704 (Red Hat 4.1.2-46) cc_compile_by : mockbuild cc_compile_domain : centos.org cc_compile_date : Tue Dec 15 20:50:26 EST 2009 xend_config_format : 2 domU xen config is: name = "koji.voismart.net" uuid = "7fc52711-974d-f475-c268-e6a8f495be5d" maxmem = 3096 memory = 3096 vcpus = 4 bootloader = "/usr/bin/pygrub" on_poweroff = "destroy" on_reboot = "restart" on_crash = "restart" vfb = [ "type=vnc,vncunused=1,keymap=it" ] disk = [ "tap:aio:/var/lib/xen/images/koji.voismart.net.img,xvda,w", "tap:aio:/var/lib/xen/images/koji.voismart.net.disk2.img,xvdb,w", "tap:aio:/var/lib/xen/images/koji.voismart.net.disk3.img.img,xvdc,w" ] vif = [ "mac=00:16:36:02:ae:f1,bridge=xenbr0,script=vif-bridge" ]
Bug 551552 looks very similar to this one.
Sorry, that should be bug 550724
Created attachment 381749 [details] Same result with upcoming 2.6.32.2-1.fc12.x86_64 I've tested the kernel 2.6.32.2-1.fc12.x86_64, from fedoraproject koji. The system seems more stable (means that takes longer to hang and needs heavier I/O) but still happens. dmesg log attached.
As I mentioned before, I think I am seeing this in bug #550724 Do you have a test that can reliably produce this problem? I can't get it to happen on a test system, only my production LTSP server. This bug I sure will get more attention, I'm sure, if a reliable test case can be found.
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