Bad file desriptors with SuSE-7.3 / samba-2.2.3a

wolfgang.glas at wolfgang.glas at
Mon Apr 8 05:51:02 GMT 2002

Dear samba team,

We have and IBM xSeries RAID5 system running under Suse-7.3 using 
kernel-2.4.16 (SuSE's kernel upgrade) with a Netgear GA621 1Gbit/s 
fiberchannel network adapter.
First we start using samba-2.2.1a from the SuSE distro and we recently 
switched to a self-compiled samba-2.2.3a.

Neither uprgrading the kernel from 2.4.10 to 2.4.16 nor upgrading samab 
from 2.2.1a to 2.2.3a resolved the described poblem:

If I switch on oplocks plus kernel oplocks, we have the following two 
errors in log.smb:

[2002/03/22 08:10:40, 0] 
  release_kernel_oplock: Error when removing kernel oplock on file 
feap/Prinz_Eugen_Bruecke/Stat_Plaene/7508__Planuebersicht.xls, de
v = 3a05, inode = 4800612, file_id = 161. Error was Bad file descriptor
[2002/04/08 13:49:36, 0] smbd/fileio.c:seek_file(53)
  seek_file: sys_lseek failed. Error was Bad file descriptor

These error occur randomly and seem to lightly related to the network 
traffic. Our machine is primarily a file server with a low CPU load and a 
file cache of about 800MB.
(Physical memory is 1 GByte)

After switching off oplocks, which was necessary due to the file 
corruptions we got, the oplock error naturally disappears, but the 
lseek-related error resides.
Supposedly, oplocks are not the direct cause of the problem, but the wrong 
file descriptors passed to the system calls.

With an even lower frequency it appears, that the content of a file is 
written to another file that was opened by the same smbd process.
(Maybe filling log.smbd with garbage or overwriting another file of the 
same user...) 

BTW, I've confirmed, that the correct compile time options 


are in samba-2.2.3a/source/Makefile in order to have off_t a 64 bit type 
and have lseek redirected to lseek64...

I do not want to make speculations about the cause of the problem, but 
somehow there might be a buffer overflow or something like this,
which overwrites the file descriptor stored by smbd and causes the above 
mentioned problems.

Please give me any kind of advice, whether such a problem is a know bug 
and will be addressed by samba-2.2.4.



Dr. Wolfgang Glas                        EV-i Informationstechnologie 
Geschäftsführer                          Sebastian-Kneipp-Weg 17
Wolfgang.Glas at                    A-6020 Innsbruck/Austria
phone: ++43-512-284883-2                 fax: ++43-512-281624-31

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