On 20/02/2016 11:44, Stefan Priebe wrote: > Hi, > > while testing Kernel 4.4.2 and starting 20 Qemu 2.4.1 virtual machines. > I got those traces and a load of 500 on those system. I was only abler > to recover by sysrq-trigger. It seems like something happening at the VM level. A task took the mm semaphore and hung everyone else. Difficult to debug without a core (and without knowing who held the semaphore). Sorry. Paolo > All traces: > > INFO: task pvedaemon worke:7470 blocked for more than 120 seconds. > Not tainted 4.4.2+1-ph #1 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > pvedaemon worke D ffff88239c367ca0 0 7470 7468 0x00080000 > ffff88239c367ca0 ffff8840a6232500 ffff8823ed83a500 ffff88239c367c90 > ffff88239c368000 ffff8845f5f070e8 ffff8845f5f07100 0000000000000000 > 00007ffc73b48e58 ffff88239c367cc0 ffffffffb66a4d89 ffff88239c367cf0 > Call Trace: > [<ffffffffb66a4d89>] schedule+0x39/0x80 > [<ffffffffb66a7447>] rwsem_down_read_failed+0xc7/0x120 > [<ffffffffb63cb594>] call_rwsem_down_read_failed+0x14/0x30 > [<ffffffffb66a6af7>] ? down_read+0x17/0x20 > [<ffffffffb617b99e>] __access_remote_vm+0x3e/0x1c0 > [<ffffffffb63cb594>] ? call_rwsem_down_read_failed+0x14/0x30 > [<ffffffffb6181d5f>] access_remote_vm+0x1f/0x30 > [<ffffffffb623212e>] proc_pid_cmdline_read+0x16e/0x4f0 > [<ffffffffb611a4cc>] ? acct_account_cputime+0x1c/0x20 > [<ffffffffb61c8348>] __vfs_read+0x18/0x40 > [<ffffffffb61c94fe>] vfs_read+0x8e/0x140 > [<ffffffffb61c95ff>] SyS_read+0x4f/0xa0 > [<ffffffffb66a892e>] entry_SYSCALL_64_fastpath+0x12/0x71 > INFO: task pvestatd:7633 blocked for more than 120 seconds. > Not tainted 4.4.2+1-ph #1 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > pvestatd D ffff88239f16fd40 0 7633 1 0x00080000 > ffff88239f16fd40 ffff8824e76a8000 ffff8823e5fc2500 ffff8823e5fc2500 > ffff88239f170000 ffff8845f5f070e8 ffff8845f5f07100 ffff8845f5f07080 > 000000000341bf10 ffff88239f16fd60 ffffffffb66a4d89 024000d000000058 > Call Trace: > [<ffffffffb66a4d89>] schedule+0x39/0x80 > [<ffffffffb66a7447>] rwsem_down_read_failed+0xc7/0x120 > [<ffffffffb63cb594>] call_rwsem_down_read_failed+0x14/0x30 > [<ffffffffb66a6af7>] ? down_read+0x17/0x20 > [<ffffffffb623206c>] proc_pid_cmdline_read+0xac/0x4f0 > [<ffffffffb611a4cc>] ? acct_account_cputime+0x1c/0x20 > [<ffffffffb60b1f23>] ? account_user_time+0x73/0x80 > [<ffffffffb60b249e>] ? vtime_account_user+0x4e/0x70 > [<ffffffffb61c8348>] __vfs_read+0x18/0x40 > [<ffffffffb61c94fe>] vfs_read+0x8e/0x140 > [<ffffffffb61c95ff>] SyS_read+0x4f/0xa0 > [<ffffffffb66a892e>] entry_SYSCALL_64_fastpath+0x12/0x71 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
