Bug 1060925

Summary: dmesg -w output not line-buffered
Product: [Fedora] Fedora Reporter: Sami Farin <hvtaifwkbgefbaei>
Component: util-linuxAssignee: Karel Zak <kzak>
Status: CLOSED CURRENTRELEASE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: unspecified    
Version: 20CC: jonathan, kzak, mluscon
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OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
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Clone Of:
: 1067354 (view as bug list) Environment:
Last Closed: 2014-10-24 14:16:35 UTC Type: Bug
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 1067354    
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Description Flags
util-linux-2.24-dmesg-follow-linebuf.patch none

Description Sami Farin 2014-02-03 23:40:23 UTC
Created attachment 858876 [details]
util-linux-2.24-dmesg-follow-linebuf.patch

Description of problem:
when writing to e.g. a pipe, output from dmesg -w can come many minutes late due to buffering.

Version-Release number of selected component (if applicable):
2.24-2

How reproducible:
100%

Steps to Reproduce:
1. dmesg -w|cat
2.
3.

Actual results:
"follow" feature does not behave like "tail -f" as expected.
dmesg write()s in about 4096 byte blocks.

Expected results:
line-buffered output

Additional info:

Comment 1 Karel Zak 2014-02-06 10:52:17 UTC
Fixed by upstream commit 3938c08cd56a7c83ea387073c1404d0e864c9fa3, Fedora package will be updated ASAP.

Thanks!

Comment 2 Karel Zak 2014-10-24 14:16:35 UTC
Fixed in v2.25 (f21)