RFR: 8268361: Fix the infinite loop in next_line

[UncleNine]

On Tue, 8 Jun 2021 16:28:34 GMT, UncleNine <github.com+1964054+UncleNine at openjdk.org> wrote:

>>> If the /proc/stat mount point is changed in container environment, the while loop may lead to 100% cpu usage.
>> 
>> In what way have you observed /proc/stat being changed which manifests in 100% cpu usage?
>
>> > If the /proc/stat mount point is changed in container environment, the while loop may lead to 100% cpu usage.
>> 
>> In what way have you observed /proc/stat being changed which manifests in 100% cpu usage?
> 
> In my case, it happened in the container environment.
> the /proc filesystem of the container is provided by lxcfs, but a lxcfs bug may make the /proc/stat mount point change.
> It was caused by a lxcfs-3.1.2 segment fault's exit

> @UncleNine please do not force push commits to an open PR as it makes it difficult for reviewers to track the changes. The PR can contain as many commits as you like as it will all be squashed to a single clean commit when integrating. Thanks.

Sorry,

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PR: https://git.openjdk.java.net/jdk/pull/4378