| Summary: | dm's hard days of corrupting kernel space AKA resuming suspended blockdev for a table reload | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Product: | [Fedora] Fedora | Reporter: | Yuri Arabadji <yuri> | ||||||||
| Component: | device-mapper | Assignee: | Orphan Owner <extras-orphan> | ||||||||
| Status: | CLOSED NOTABUG | QA Contact: | Fedora Extras Quality Assurance <extras-qa> | ||||||||
| Severity: | unspecified | Docs Contact: | |||||||||
| Priority: | unspecified | ||||||||||
| Version: | 15 | CC: | agk, bmarzins, dwysocha, extras-orphan, heinzm, jonathan, mbroz, prockai | ||||||||
| Target Milestone: | --- | ||||||||||
| Target Release: | --- | ||||||||||
| Hardware: | Unspecified | ||||||||||
| OS: | Unspecified | ||||||||||
| Whiteboard: | |||||||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||||||
| Doc Text: | Story Points: | --- | |||||||||
| Clone Of: | Environment: | ||||||||||
| Last Closed: | 2011-05-01 13:28:57 UTC | Type: | --- | ||||||||
| Regression: | --- | Mount Type: | --- | ||||||||
| Documentation: | --- | CRM: | |||||||||
| Verified Versions: | Category: | --- | |||||||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||||||
| Attachments: |
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Created attachment 496059 [details]
fc15 kernel crash info
Created attachment 496060 [details]
centos 5.6 kernel trace
I glanced at the first example - it's not a bug, you created a loop! Bugzilla is for dealing with bugs - please use mailing lists (e.g. dm-devel) or IRC if you need usage help. Indeed I did! What a stupid mistake, src.ptr supposed to have src's table, not pointer to src :) And with that error corrected, everything works as it should. What a flexible software this device-mapper is :) Alasdair, thanks for pointing out the mistake and for suggestions on IRC, it will make my journey through dm land much easier. And for anyone coming here from google, if you've got that stack trace, you have a loop :) |
Created attachment 496058 [details] fc14 kernel crash info The thing's happening everywhere, on each latest FC and, more importantly (for me), on CentOS 5.6. Description of problem: dm's doing bad things where it shouldn't. I would be fine with just "doesn't compute" in case it's supplied wrong or meaningless parameters. As discussed in IRC, i'm trying to implement pvmove-like functionality using userspace and for general blockdevs. That is, a live data migration from one blockdev to another. Here's a test case #1, centos 5.6: ============================== root.net [~]# dmsetup create src.ptr 0 2097152 linear /dev/fused/src 0 root.net [~]# dmsetup suspend /dev/fused/src root.net [~]# dmsetup create src.mir 0 2097152 mirror core 2 1024 block_on_error 2 /dev/mapper/src.ptr 0 /dev/fused/dst 0 root.net [~]# dmsetup reload /dev/fused/src 0 2097152 linear /dev/mapper/src.mir 0 root.net [~]# dmsetup resume fused-src Read from remote host x30.fused.net: Connection reset by peer ============================== test case #2, FC14,15, essentially the same. I've tried various combinations of suspension and resuming, no one worked. ============================== echo '0 1048576 linear /dev/base/src 0' | dmsetup create src.ptr dmsetup suspend /dev/base/src echo '0 1048576 linear /dev/sdb 0' | dmsetup create dst.ptr echo '0 1048576 mirror core 1 1024 2 /dev/mapper/src.ptr 0 /dev/mapper/dst.ptr 0' | dmsetup create src.mir echo '0 1048576 linear /dev/mapper/src.mir 0' | dmsetup reload /dev/base/src dmsetup resume /dev/base/src ============================== I would be highly grateful if you could fix this or at least tell me the right way to do it. Thanks.