Currently, we skip doing the is_path_accessible check in cifs_mount if there is no prefixpath. There is a report of at least one server however that allows a TREE_CONNECT to a share that has a DFS referral at its root. UNC that had no prefixpath was used in that case, so the is_path_accessible check was not triggered and the box later hit a BUG() because we were chasing a DFS referral on the root dentry for the mount. Upstream fix: 70945643722ffeac779d2529a348f99567fa5c33 References: https://bugzilla.redhat.com/show_bug.cgi?id=682829 https://github.com/torvalds/linux/commit/70945643722ffeac779d2529a348f99567fa5c33 Acknowledgements: Red Hat would like to thank Yogesh Sharma for reporting this issue.
Statement: This issue affects the Linux kernel as shipped with Red Hat Enterprise Linux 4, 5, 6, and Red Hat Enterprise MRG. Red Hat Enterprise Linux 4 is now in Production 3 of the maintenance life-cycle, https://access.redhat.com/support/policy/updates/errata/, therefore the fix for this issue is not currently planned to be included in the future updates. This has been addressed in Red Hat Enterprise Linux 5, 6 and Red Hat Enterprise MRG via https://rhn.redhat.com/errata/RHSA-2011-1479.html, https://rhn.redhat.com/errata/RHSA-2011-1465.html, and https://rhn.redhat.com/errata/RHSA-2012-0010.html.
I believe this also requires: commit 221d1d797202984cb874e3ed9f1388593d34ee22 cifs: add fallback in is_path_accessible for old servers
Created kernel tracking bugs for this issue Affects: fedora-all [bug 748687]
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2011:1465 https://rhn.redhat.com/errata/RHSA-2011-1465.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Via RHSA-2011:1479 https://rhn.redhat.com/errata/RHSA-2011-1479.html
This issue has been addressed in following products: MRG for RHEL-6 v.2 Via RHSA-2012:0010 https://rhn.redhat.com/errata/RHSA-2012-0010.html