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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 active requests 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): kernel 2.4.21 How reproducible: sometimes Steps to Reproduce: normal usage of nbd driver and utilities causes kernel oops Actual results: kernel oops Expected results: no kernel oops Additional info:
Created attachment 96954 [details] patch file
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: http://www.redhat.com/security/updates/errata/ 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.