Bug 154639 (IT_71391)
Summary: | kernel thread current->mm dereference in grab_swap_token causes oops | ||
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Product: | Red Hat Enterprise Linux 4 | Reporter: | Keith Holder <keith.holder> |
Component: | kernel | Assignee: | Rik van Riel <riel> |
Status: | CLOSED ERRATA | QA Contact: | Brian Brock <bbrock> |
Severity: | high | Docs Contact: | |
Priority: | medium | ||
Version: | 4.0 | CC: | davej, linux26port, rkenna, tao |
Target Milestone: | --- | ||
Target Release: | --- | ||
Hardware: | All | ||
OS: | Linux | ||
Whiteboard: | |||
Fixed In Version: | Doc Type: | Bug Fix | |
Doc Text: | Story Points: | --- | |
Clone Of: | Environment: | ||
Last Closed: | 2005-06-08 15:14:07 UTC | Type: | --- |
Regression: | --- | Mount Type: | --- |
Documentation: | --- | CRM: | |
Verified Versions: | Category: | --- | |
oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
Cloudforms Team: | --- | Target Upstream Version: | |
Embargoed: | |||
Bug Depends On: | |||
Bug Blocks: | 231639 |
Description
Keith Holder
2005-04-13 09:08:25 UTC
I'll submit a (trivial) patch for the RHEL4 kernel to ignore a current->mm of NULL. Btw, note that for most kernel threads current->mm tends to be &init_mm... Btw, have you verified that adding the check really fixes the issue, or does the kernel simply crash elsewhere? I am not 100% sure that running any task with a NULL ->mm is valid... When calling daemonize() to create a kernel thread, it calls exit_mm(). This sets tsk->mm to NULL and the thread/process runs with a 'lazy_tlb'. Also, I thought all kernel threads didn't have an address space, hence mm is supposed to be NULL. You're right. Hmmm, I could've sworn they got moved to &init_mm. Anyway, the patch has been submitted for inclusion into RHEL4 yesterday, and got approved. Thank you for alerting us to this bug. I have run a Veritas specific stress test (odmstress) non-stop for over 100 hours with this patch fix (U1-kernel-2.6.9-6.43) and the testing was successful. An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHSA-2005-420.html |