topic Re: Core dump SIGSEGV (in strcpy) in Operating System - HP-UX

Core dump

prabhakarbhatt — Tue, 22 Jan 2013 12:20:15 GMT

Dear,

I see the following core dump in strcpy. Please could suggest some pointers if you hace faced this already!!!

Program terminated with signal 11, Segmentation fault.

SEGV_MAPERR - Address not mapped to object

#0 0x60000000c01f2720:0 in strcpy+0x480 () from /usr/lib/hpux32/libc.so.1

(gdb) bt

#0 0x60000000c01f2720:0 in strcpy+0x480 () from /usr/lib/hpux32/libc.so.1

Regards,

Prabhakar

Re: Core dump

Steven Schweda — Wed, 23 Jan 2013 04:09:27 GMT

Re: Core dump SIGSEGV (in strcpy)

Dennis Handly — Wed, 23 Jan 2013 07:13:48 GMT

As Steven said, you need to look at the values being passed to strcpy.

At the start of strcpy, $r32 contains the target and $r33 contains the source.

You could have ran off the end of either source or target. Or trying to write to readonly data.

What libc patch do you have?

Using these gdb commands may help:

info reg

disas $pc-16*12 $pc+16*4

Re: Core dump SIGSEGV (in strcpy)

prabhakarbhatt — Wed, 30 Jan 2013 17:57:19 GMT

Dear Dennis ,

I found that "r8" register contains the address of r32 in frame 0. After examining the "r8" address I am getting invalid address. Pls can you confirm is my analysis correct or not

(gdb) frame 0
#0 0x60000000c01f2720:0 in strncat+0x20 () from /usr/lib/hpux32/libc.so.1
(gdb) x $r8
0xc18004c: Cannot access memory at address 0xc18004c
(gdb) x/x $r8

full output of "disas" is attached

Thanks and Regards,

Prabhakar Bhatt

Re: Core dump SIGSEGV (in strcpy)

Dennis Handly — Wed, 30 Jan 2013 21:07:59 GMT

>I found that "r8" register contains the address of r32 in frame 0. ... Pls can you confirm is my analysis correct or not

I see no register dump. And you can't get addresses of registers, unless you are talking about the RSE.

>#0 0x60000000c01f2720:0 in strncat+0x20 /usr/lib/hpux32/libc.so.1

This is not the libc.so.1 on the system that aborted. All debugging must be done there or with a packcore.

>full output of "disas" is attached

But not of strcpy where it aborted.

Re: Core dump SIGSEGV (in strcpy)

prabhakarbhatt — Mon, 04 Feb 2013 12:14:02 GMT

Dear,

Pls find the proper bt with its replated packcore and frame 0 data is attached:

(gdb) bt
#0 0x200000007e5aa430:0 in strcpy+0x190 () at locinst.cpp:561

Pls can youo let me know which reg contains the source/destination in the attaced disas

Thanks and Regards,

Prabhakar Bhatt

Re: Core dump SIGSEGV (in strcpy)

Dennis Handly — Tue, 05 Feb 2013 08:52:15 GMT

>frame 0 data is attached:

Again, I don't see a register dump.

>can you let me know which reg contains the source/destination in the attached disas

0x200000007e5aa430:0 <strcpy+0x190>: (p15) st8 [r31]=r35,8

r31 is the current 8 byte aligned target, masked from r32. r30 is the next aligned source.

Note: The loop is pipelined with rotating registers.