| Summary: | lvs cache_policy shows corrupted characters when large number of cached lvs are listed | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 7 | Reporter: | Dustin Black <dblack> |
| Component: | lvm2 | Assignee: | Peter Rajnoha <prajnoha> |
| lvm2 sub component: | Command-line tools | QA Contact: | cluster-qe <cluster-qe> |
| Status: | CLOSED NEXTRELEASE | Docs Contact: | |
| Severity: | low | ||
| Priority: | unspecified | CC: | agk, heinzm, jbrassow, msnitzer, prajnoha, prockai, thornber, zkabelac |
| Version: | 7.2 | ||
| Target Milestone: | rc | ||
| Target Release: | --- | ||
| Hardware: | Unspecified | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2017-04-27 11:14:23 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
Could you please show the output? Also, RHEL7.3 is out, could you test with that please? I think this is already fixed with https://sourceware.org/git/?p=lvm2.git;a=commit;h=a83d611a86e6da31f255d5d87adf14cb3d62a05a The fix appeared in lvm2 v2.02.140. It was a regression since lvm2 v2.02.126. I checked the lvm2-2.02.130-5.el7_2.5.x86_64 with valgrind and I hit the problems for which this patch was aimed for - that patch is not included in 7.2.z yet (not sure if we want to backport that or not). It should fixed in 7.3 and higher releases. With valgrind, this problem is exposed as: #valgrind lvs -a -o name,vg_name,size,pool_lv,devices,cachemode,cache_policy,cache_settings,chunksize ... ==10689== Invalid read of size 1 ==10689== at 0x4C30B5B: strnlen (vg_replace_strmem.c:421) ==10689== by 0x5B96AA4: vfprintf (vfprintf.c:1637) ==10689== by 0x5BC0488: vsnprintf (vsnprintf.c:114) ==10689== by 0x54CFB23: dm_snprintf (libdm-string.c:129) ==10689== by 0x54C5E8C: _output_field (libdm-report.c:4244) ==10689== by 0x54C684E: _output_as_columns (libdm-report.c:4390) ==10689== by 0x54C6B3A: dm_report_output (libdm-report.c:4434) ==10689== by 0x15CE0C: _report (reporter.c:934) ==10689== by 0x15CF0A: lvs (reporter.c:953) ==10689== by 0x14E560: lvm_run_command (lvmcmdline.c:1655) ==10689== by 0x14FB49: lvm2_main (lvmcmdline.c:2121) ==10689== by 0x172BEF: main (lvm.c:22) |
Description of problem: Running the `lvs` command with many fields including -o cache_policy and passing a significant number of VGs with cached LVs to the command results in corrupted output in the 'Cache Policy' column. Version-Release number of selected component (if applicable): # rpm -qa |grep lvm2 lvm2-2.02.130-5.el7_2.5.x86_64 lvm2-libs-2.02.130-5.el7_2.5.x86_64 How reproducible: Consistently Steps to Reproduce: 1.Create more than 5 cached LVs 2.Run `lvs -a -o name,vg_name,size,pool_lv,devices,cachemode,cache_policy,cache_settings,chunksize vg{a..f}` Actual results: Most fields in the 'Cache Policy' column show corrupted characters. Expected results: All 'Cache Policy' fields should correctly show the current policy. Additional info: Appears to be some kind of buffer overflow. The persistence of the issue is dependent on the number of fields displayed in the `lvs` output. For me with the command above,listing the output from 5 VGs works, but 6 VGs shows the corrupted characters. If I reduce the number of fields, 6 VGs may work and 7 may fail.