Red Hat Bugzilla – Bug 113438
race conditions in 2.4.21 kernel nbd driver
Last modified: 2007-11-30 17:07:00 EST
Description of problem:
There are several race conditions in the 2.4.21 kernel nbd driver
that can cause a kernel oops. A patch has been accepted by the 2.4
kernel maintainer (Marcelo Tosatti) circa 2.4.22-preX release. The
2.4.21 kernel in RHEL3 is susceptible to these problems. The patch to
fix these problems is attached.
Specifically, the patch fixes the following problems:
1) adds locking and properly orders the code in NBD_CLEAR_SOCK to
eliminate races with other code
2) adds an lo->sock check to nbd_clear_que to eliminate races between
do_nbd_request and nbd_clear_que, which resulted in the dequeuing of
3) adds an lo->sock check to NBD_DO_IT to eliminate races with
NBD_CLEAR_SOCK, which caused an Oops when "nbd-client -d" was called
Version-Release number of selected component (if applicable):
Steps to Reproduce:
normal usage of nbd driver and utilities causes kernel oops
no kernel oops
Created attachment 96954 [details]
Looks like this patch still isn't in 2.4.21-20.EL.
This bug is filed against RHEL 3, which is in maintenance phase.
During the maintenance phase, only security errata and select mission
critical bug fixes will be released for enterprise products. Since
this bug does not meet that criteria, it is now being closed.
For more information of the RHEL errata support policy, please visit:
If you feel this bug is indeed mission critical, please contact your
support representative. You may be asked to provide detailed
information on how this bug is affecting you.