Bug 109147

Summary:	vmstat dies parsing /proc/stats
Product:	Red Hat Enterprise Linux 3	Reporter:	Shantanu Goel <sgoel01>
Component:	procps	Assignee:	Karel Zak <kzak>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	3.0	CC:	laroche
Target Milestone:	---
Target Release:	---
Hardware:	i686
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2005-05-20 03:25:49 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:	132991

Description Shantanu Goel 2003-11-04 23:52:04 UTC

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Description of problem:
Running "vmstat 3" eventually dies with the following error:

open: No such file or directory
error: failed to parse /proc/stats


I am running kernel-smp-2.4.22-1.2115.nptl on a Dell 1600SC with dual
Xeon CPUs.  I have encountered this error with earlier test kernels as
far back as 2088 as well.


Version-Release number of selected component (if applicable):
procps-2.0.17-1

How reproducible:
Sometimes

Steps to Reproduce:
Run "vmstat 3".

Actual Results:  vmstat dies eventually.  The timing is erratic but
pretty much reproducible every time.

Additional info:

Comment 1 Daniel Walsh 2004-02-11 13:56:27 UTC

Can you reproduce this with procps 3.1.15?

Comment 2 Brian Hirt 2004-07-27 18:28:58 UTC

this seems to be fixed in procps 3.x, but exists in procps 2.0.17 which is what core one 
uses.   I have the answer to this problem.:

I did a strace and looked at the code and i've found what i think is a problem.  there is a 
race condition in getrunners() if a program exits between the readdir(proc) and the open() 
vmstat will die.    if /proc/pid/stat is missing, I think it should be assumed that the 
process has died, and continue gracefully if the errno is file not found.  look at line 48 
vmstat.c in 2.0.17


strace reveals:

open("/proc/16928/stat", O_RDONLY)      = 5
read(5, "16928 (bash) S 16908 10483 4568 "..., 1023) = 209
close(5)                                = 0
open("/proc/16929/stat", O_RDONLY)      = -1 ENOENT (No such file or directory)
dup(2)                                  = 5
fcntl64(5, F_GETFL)                     = 0x2 (flags O_RDWR)
fstat64(5, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 
0xbf512000
_llseek(5, 0, 0xbff811b8, SEEK_CUR)     = -1 ESPIPE (Illegal seek)
write(5, "open: No such file or directory\n", 32open: No such file or directory
) = 32
close(5)                                = 0
munmap(0xbf512000, 4096)                = 0
write(2, "error: failed to parse /proc/sta"..., 35error: failed to parse /proc/stats
) = 35
munmap(0xbf513000, 4096)                = 0
exit_group(1)                           = ?

Comment 5 Karel Zak 2004-11-23 18:05:21 UTC

For RHEL3 fixed in procps-2.0.17-13.1.

Comment 6 Dennis Gregorovic 2005-05-20 03:25:49 UTC

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/RHBA-2005-156.html