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Opened 7 years ago

#480 new enhancement

VFS deadlocks when FS calles VFS operation (namespace_rwlock)

Reported by: Zdenek Bouska Owned by: Jakub Jermář
Priority: major Milestone:
Component: helenos/srv/vfs Version: mainline
Keywords: Cc:
Blocker for: Depends on:
See also:

Description

Jakub on mailing list:

The solution with a global namespace lock traded flexibility for
simplicity. When your fs implementation uses the VFS input interface
(e.g. via libc wrappers) it always creates a possibility for a deadlock
because it creates a loop and there may always be some locks taken or
resources consumed along the codepaths that form the loop. The more
operations this loop involves, the more likely it is that there will be
a deadlock.

We should probably change this behavior and remove this inflexibility as
it is a potential security problem at the same time; if we want to have
unprivileged file systems (or just privileged less than VFS), VFS needs
to be able to gracefully survive someone's attempt to do crazy stuff.

http://lists.modry.cz/cgi-bin/private/helenos-devel/2012-August/008685.html
http://lists.modry.cz/cgi-bin/private/helenos-devel/2012-August/008691.html
http://lists.modry.cz/cgi-bin/private/helenos-devel/2012-August/008692.html
http://lists.modry.cz/cgi-bin/private/helenos-devel/2012-August/008693.html

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