Am 22.02.2016 um 18:36 schrieb Paolo Bonzini:
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.
OK thank you anyway. Is there anything i can do if this happens again?
Stefan
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
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