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| author | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2011-01-09 23:34:42 +0100 |
|---|---|---|
| committer | Samuel Thibault <samuel.thibault@ens-lyon.org> | 2011-01-09 23:34:42 +0100 |
| commit | f3df65ce34153357d28bee621bdf49b61e68b182 (patch) | |
| tree | 25ac416b157b010ca2f942dac5c5ba0b38a924ac /open_issues/locking.mdwn | |
| parent | 09184ae09c44c052a207aa5c6dc8ce9cf61a343f (diff) | |
| parent | 3bbe62327128ce85829a4cb2fb429bd8f21b4d75 (diff) | |
Merge branch 'master' of flubber:~hurd-web/hurd-web
Diffstat (limited to 'open_issues/locking.mdwn')
| -rw-r--r-- | open_issues/locking.mdwn | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/open_issues/locking.mdwn b/open_issues/locking.mdwn new file mode 100644 index 00000000..11a10524 --- /dev/null +++ b/open_issues/locking.mdwn @@ -0,0 +1,40 @@ +[[!meta copyright="Copyright © 2008, 2009, 2010 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]]."]]"""]] + +[[!tag open_issue_hurd]] + +Every now and then, new locking issues are discovered in +[[hurd/libdiskfs]] or [[hurd/translator/ext2fs]], for example. Nowadays +these in fact seem to be the most often encountered cause of Hurd crashes +/ lockups. + +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 [[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|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|multithreading]] applications. + +Tools have been written for automated [[code analysis]]; these can help to +locate and fix such errors. |