This technote explains why attempts to run any application that sets file locks in a version 2003.06.00 IBM Rational ClearCase view and VOB context causes Red Hat® Linux® with kernel 2.6.9-42 to panic.
While running on Red Hat Enterprise Linux 4 (RHEL4) on kernel 2.6.9-22 and -34 applications that sets file locks in a VOB/View context worked as expected. After upgrading to 2.6.9-42 these same applications caused a kernel panic.
The following are examples of the output from a resulting crash:
The cause is a combination of two issues:
- Kernel Related Problem from Red Hat (kernel bug):
RIT117294-NFS randomly returns EINTR on lock removal and causes a panic condition within the Kernel.
This issue has been confirmed by Red Hat to be a kernel bug caused by issues with the file system not handling file locking correctly.
There is a current bug against this issue with Red Hat, #1361130.
- ClearCase Related Problem with MVFS: Defect APAR PK25224 was submitted to address the issue.
Resolving the problem
- Contact Red Hat to obtain a fix for the NFS kernel bug.
This issue has been confirmed by RedHat to be a kernel bug caused by issues with the file system not handling file locking correctly. Refer to following errata kernel notes for more information concerning the bug:
Before you apply the above errata (or later erratas for RedHat Enterprise 4 U6, or later kernels beyond U6) to a ClearCase system with MVFS installed, you will be required to apply a fix to resolve the issue reported in APAR PK61579. Refer to technote 1296516 for further information.
- Apply the patches which resolve defect APAR PK25224. Review technote 1240506 for more details.
IMPORTANT: Both of the above fixes (Red Hat kernel and ClearCase MVFS) will be necessary to fully resolve this issue.