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Diffstat (limited to 'community/gsoc/project_ideas/libdiskfs_locking.mdwn')
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diff --git a/community/gsoc/project_ideas/libdiskfs_locking.mdwn b/community/gsoc/project_ideas/libdiskfs_locking.mdwn new file mode 100644 index 00000000..faac8bd9 --- /dev/null +++ b/community/gsoc/project_ideas/libdiskfs_locking.mdwn @@ -0,0 +1,45 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010, 2011 Free Software Foundation, +Inc."]] + +[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable +id="license" text="Permission is granted to copy, distribute and/or modify this +document under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no Invariant +Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license +is included in the section entitled [[GNU Free Documentation +License|/fdl]]."]]"""]] + +[[!meta title="Fix libdiskfs Locking Issues"]] + +[[!tag open_issue_hurd]] + +Nowadays the most often encountered cause of Hurd crashes seems to be lockups +in the [[hurd/translator/ext2fs]] server. One of these could be traced +recently, and turned out to be a lock inside [[hurd/libdiskfs]] that was taken +and not released in some cases. There is reason to believe that there are more +faulty paths causing these lockups. + +The task is systematically checking the [[hurd/libdiskfs]] code for this kind of locking +issues. To achieve this, some kind of test harness has to be implemented: For +example instrumenting the code to check locking correctness constantly at +runtime. Or implementing a [[open_issues/unit_testing]] framework that explicitly checks +locking in various code paths. (The latter could serve as a template for +implementing unit tests in other parts of the Hurd codebase...) + +(A [[systematic code review|open_issues/security]] would probably suffice to find the +existing locking +issues; but it wouldn't document the work in terms of actual code produced, and +thus it's not suitable for a GSoC project...) + +This task requires experience with debugging locking issues in +[[multithreaded|open_issues/multithreading]] applications. + +Tools have been written for automated [[open_issues/code_analysis]]; these can help to +locate and fix such errors. + +Possible mentors: Samuel Thibault (youpi) + +Exercise: If you could actually track down and fix one of the existing locking +errors before the end of the application process, that would be excellent. This +might be rather tough though, so probably you need to talk to us about an +alternative exercise task... |