Possible memory leak in sf_follow_link (vboxsf.ko module) => Fixed in SVN

[Eugene]

There is a possibility for a memory leak in sf_follow_link() function (src/VBox/Additions/linux/sharedfolders/lnkops.c).

The page allocated there via get_zeroed_page(GFP_KERNEL) will probably never be freed if vboxReadLink() fails. This happens, for example, when the shared folder contains a Windows symlink (a junction, to be exact) to a directory and one tries to list the contents of that directory from the guest or just cd to it via the link.

If I understand correctly what happens there, neither vboxReadLink() nor sf_follow_link() free that page, so it remains allocated and the pointer to it is lost when sf_follow_link() ends.

Host: Windows XP SP3 x86
Guest: OpenSUSE 11.3 x86
Guest Additions: 4.0.3 (r69551)

Attached are the VM log, VM configuration and the file with the call stacks of the memory leaks of this kind.

This problem as well as those reported in tickets #7705 and #7720 was detected by ​KEDR analysis system for Linux kernel modules.

[Eugene]

VM log

[Eugene]

VM configuration

[Eugene]

Technical data about the leaks

[Frank Mehnert]

That is absolutely correct. Thanks for this hint and thanks for the link! Fixed in r35854.

[Eugene]

Great! I'm glad it was helpful.