Messages in this thread | | | Date | Tue, 12 Jun 2012 15:09:24 -0700 | From | Daniel Walker <> | Subject | hung_task checking and sys_sync |
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I found this commit which was a while ago,
commit fb822db465bd9fd4208eef1af4490539b236c54e Author: Ingo Molnar <mingo@elte.hu> Date: Wed Aug 20 11:17:40 2008 +0200
softlockup: increase hung tasks check from 2 minutes to 8 minutes
Andrew says:
> Seems that about 100% of the reports we get of this warning triggering > are sys_sync, transaction commit, etc. increase the timeout. If it still triggers for people, we can kill it. Signed-off-by: Ingo Molnar <mingo@elte.hu>
We're seeing these messages on an older kernel (montavista) but the code areas appear similar to current kernels. The issue is that we're doing a file copy which takes 10-15minutes, and in the background there is a "df --sync" happening (which is calling sys_sync). We end up getting a hung task message like below,
INFO: task df:1778 blocked for more than 120 seconds. "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. ffffffff81578d40 0000000000000086 ffff8801f6135b00 ffff880269a91800 ffff880269a91800 ffff8802702be000 ffff8801f602a080 0000000000000000 ffff8801f602a440 ffffffff8109c166 ffff8801e863de18 0000000000000004 Call Trace: [<ffffffff8109c166>] ? sync_page+0x0/0x49 [<ffffffff81320de2>] ? __schedule+0x3c/0x57 [<ffffffff810ea3c7>] ? bdi_sched_wait+0x0/0xe [<ffffffff81320de2>] ? __schedule+0x3c/0x57 [<ffffffff81320e0d>] ? schedule+0x10/0x1e [<ffffffff810ea3d0>] ? bdi_sched_wait+0x9/0xe
There some variation in the stack trace , but always thru bdi_sched_wait().
These don't seem like valid warnings, since the copy happening is know to take a long time. Has there been any commit that disable these messages bdi_sched_wait?
Daniel
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