kern/131602: sendfile() sends corrupted data

[Peter Trifonov]

>Number:         131602
>Category:       kern
>Synopsis:       sendfile() sends corrupted data
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Feb 12 08:30:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Peter Trifonov
>Release:        7.1
>Organization:
Saint-Petersburg State Polytechnic University
>Environment:
FreeBSD dcn.research.dcn 7.1-RELEASE FreeBSD 7.1-RELEASE #1: Mon Jan  5 15:19:14 MSK 2009     petert-admin at dcn.research.dcn:/usr/obj/usr/src/sys/SERVER  i386
>Description:
The server hosts a large collection of files, which are stored on a local IDE hard disk. The files are available both via Apache 2.2.11 web server and Samba 3.0.32. Sometimes both Apache and Samba return to clients corrupted files. If the corrupted file is returned by Apache, all subsequent requests to this file from Samba also return corrupted file, and vice versa. The problem arises sporadically (but quite often) for different files larger than 1M. 
The problem is not persistent, i.e. some files are later delivered correctly. 
Disabling sendfile BOTH in Apache and Samba solves the problem.
>How-To-Repeat:
Put a file larger than 1M to a directory available both via apache and samba. Try to download it via both of them. Compare md5 checksums of the original and downloaded files. 
>Fix:


>Release-Note:
>Audit-Trail:
>Unformatted: