[User-mode-linux-devel] Re: test9 - finally some action on stack_check_overflow!

[William S. <wst...@po...>]

On Wed, 4 Oct 2000, Jeff Dike wrote:

> wst...@po... said:
> > VFS: Mounted root (ext2 filesystem) readonly. 
> > Mounted devfs on /dev
> > INIT: version 2.78 booting 
> > Kernel panic: Stack overflowed onto current_task page from set_signals 
> 
> I need a stack trace from the panicing thread, not the tracing thread.
> 
> Put 'debug' on the command line, and when it panics, ^C and get the backtrace.

	Hmm, after all the work you put into debugging tools, wouldn't it
be nice if your users actually _used_ them?  *grin*
	Here it is - it's from my debug kernel.

b00000e
att 1
b start_kernel
c
GNU gdb 5.0
Copyright 2000 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you
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welcome to change it and/or distribute copies of it under certain
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Type "show copying" to see the conditions.
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This GDB was configured as "i386-redhat-linux"...
(gdb) att 1
Attaching to program: /home/wstearns/uml/rh6.2/linux, Pid 1
0x100a9711 in __default_morecore (increment=27134)
    at ../sysdeps/generic/morecore.c:48
48      ../sysdeps/generic/morecore.c: No such file or directory.
(gdb) b start_kernel
Breakpoint 1 at 0x100e4b8c: file init/main.c, line 505.
(gdb) c
Continuing.

Program received signal SIGSEGV, Segmentation fault.
0x10038fbd in add_gd_partition (hd=0x40013994, minor=18, start=1343099424, 
    size=96) at check.c:175
175             hd->part[minor].start_sect = start;
(gdb) bt
#0  0x10038fbd in add_gd_partition (hd=0x40013994, minor=18,
start=1343099424, 
    size=96) at check.c:175
#1  0x50053c40 in ?? ()
#2  0x10039a76 in msdos_partition (hd=0x50053d18, dev=1343086976, 
    first_sector=1342520512, first_part_minor=1342524448) at msdos.c:480
#3  0x1003a352 in ext2_new_block (inode=0x50053df8, goal=0, 
    prealloc_count=0x50053de0, prealloc_block=0x1002824a, err=0xffffffff)
    at
/usr/src/uml-linux/linux-2.4.0-test8.uml/include/asm/arch/string.h:552
#4  0x10028d40 in sys_mknod (filename=0x50053df8 "\177ELF\001\001\001", 
    mode=0, dev=20485) at namei.c:1214
#5  0x10028f38 in d_unhash (dentry=0x100fae6d) at namei.c:1307
#6  0x1009e221 in tracing_cb (proc=0x100fae6d <tvecs+38221>,
arg=0x1012a140)
    at process_kern.c:301
#7  0x1009e264 in do_proc_op (t=0x100fae6d, proc_id=269656384)
    at process_kern.c:324
#8  0x10001395 in flush_signals (t=0x0) at signal.c:108
#9  0x100a3a02 in sigaddset (set=0x50052000, signo=0) at sigaddset.c:29
(gdb) bt
#0  0x10038fbd in add_gd_partition (hd=0x40013994, minor=18,
start=1343099424, 
    size=96) at check.c:175
#1  0x50053c40 in ?? ()
#2  0x10039a76 in msdos_partition (hd=0x50053d18, dev=1343086976, 
    first_sector=1342520512, first_part_minor=1342524448) at msdos.c:480
#3  0x1003a352 in ext2_new_block (inode=0x50053df8, goal=0, 
    prealloc_count=0x50053de0, prealloc_block=0x1002824a, err=0xffffffff)
    at
/usr/src/uml-linux/linux-2.4.0-test8.uml/include/asm/arch/string.h:552
#4  0x10028d40 in sys_mknod (filename=0x50053df8 "\177ELF\001\001\001", 
    mode=0, dev=20485) at namei.c:1214
#5  0x10028f38 in d_unhash (dentry=0x100fae6d) at namei.c:1307
#6  0x1009e221 in tracing_cb (proc=0x100fae6d <tvecs+38221>,
arg=0x1012a140)
    at process_kern.c:301
#7  0x1009e264 in do_proc_op (t=0x100fae6d, proc_id=269656384)
    at process_kern.c:324
#8  0x10001395 in flush_signals (t=0x0) at signal.c:108
#9  0x100a3a02 in sigaddset (set=0x50052000, signo=0) at sigaddset.c:29
(gdb) 

	Cheers,
	- Bill

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William Stearns (wst...@po...).  Mason, Buildkernel, named2hosts, 
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