FreeTDS Development Group

["Lowden, James K" <LowdenJK AT bernstein.com>]

> From: Gustavo A. Gonzalez
> Sent: Tuesday, August 30, 2005 9:20 AM
> 
> hi all!...im working with dblib to process some stored procedures with SQL
> SERVER and in a while, processing that sps results in a SIGSEGV and core
> dump. In my pourposes to solve that problem i get from gdb the following
> lines:
> 
> #0  0x005fc9b3 in main_arena () from /lib/tls/libc.so.6
> #1  0x005fc8c8 in main_arena () from /lib/tls/libc.so.6
> #2  0x00595d3c in ___newselect_nocancel () from /lib/tls/libc.so.6
> #3  0xf64e364b in goodread (tds=0xd96d3d8, buf=0xfbad8001 <Address
> 0xfbad8001 out of bounds>, buflen=227988440) at read.c:114
             ^^^^^^^^^^^^^ 
> #4  0xf64e3756 in goodread (tds=0x5fc911, buf=0xf4725c70 "ô¯_", buflen=8) 
> at read.c:176
> #5  0xf64e3959 in tds_read_packet (tds=0xd96d3d8) at read.c:508
> #6  0xf64e3cc7 in tds_get_byte (tds=0xd96d3d8) at read.c:209
> #7  0xf64e3d12 in tds_peek (tds=0xd96d3d8) at read.c:232
> #8  0xf64d1141 in dbsqlok (dbproc=0xf64f358f) at dblib.c:3888

Congratulations!  This kind of problem was pretty common a few years ago, but 
has gotten pretty rare in the network library.  Thanks for finding it.

> But i don't know where is the problem ....any ideas about what causes a
> sigsegv? 

Same thing as always.  Trying to use unallocated memory.  The bane of C.

Obviously dbsqlok() tries to read from the network, gets 8 bytes of 
something, and then gets in real trouble on line 114 (frame #3).  It's all 
downhill from there.  

It's hard to diagnose with only the bt.  Can you post a TDSDUMP log and its 
bt?  That should show us what the server sent and let us see if there's a 
protocol problem.  

Regards, 

--jkl

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