ls -l segfault

[Jan Evert van Grootheest]

Hi again,

	-----Oorspronkelijk bericht-----
	Van: busybox-bounces at busybox.net [mailto:busybox-bounces at busybox.net] Namens Jan Evert van Grootheest
	Verzonden: woensdag 14 maart 2007 12:02
	Aan: busybox at busybox.net
	Onderwerp: ls -l segfault
	
	
	Hi all,
	 
	I'm having the same problem as discussed in thread http://busybox.net/lists/busybox/2007-February/026158.html.
	Unfortunately, that thread ends inconclusive.
	 
	It's exactly as described there:
	- large directories (like /bin) fail with ls -l and smaller ones (/etc) succeed
	- it only fails when executed as 'ls -l /bin' and does not fail as 'busybox ls -l /bin'
	- 'ls -l /bin' and 'cd /bin; ls -l' both fail
	- other ls options do not cause failure (tested each option as single option)
	 
	
	Environment is linux 2.6.16.43  + Ingos -rt patch. Gcc 4.1.2, glibc 2.3.6. And busybox 1.4.1 with the 5 patches.
	 
	So I made a debug busybox.
	(noticed that CONFIG_DEBUG_PESSIMIZE does not make a difference; the compiler command line is the same with and without)
	And made a coredump:
	(gdb) bt full
	#0  showfiles (dn=0x80c2fe8, nfiles=254) at coreutils/ls.c:559
	        i = 160
	        ncols = 1
	        nrows = 254
	        row = 160
	        nc = 0
	        column = 0
	        nexttab = 0
	        column_width = 0 

Examining the memory behind *dn reveals the directory listing.
So I guess there are two overlapping memory regions. Somehow.
 
-- Jan Evert

	 
	#1  0x08058f1d in showdirs (dn=0x80c2160, ndirs=1, first=1) at coreutils/ls.c:461
	        i = 0
	        nfiles = 135016424
	        subdnp = (struct dnode **) 0x80c2fe8
	        dndirs = <value optimized out>
	        dnd = <value optimized out>
	#2  0x0805933b in ls_main (argc=3, argv=0x80be66c) at coreutils/ls.c:941
	        dnd = (struct dnode **) 0x80c2160
	        dnf = (struct dnode **) 0x0
	        dnp = <value optimized out>
	        dn = <value optimized out>
	        cur = <value optimized out>
	        opt = <value optimized out>
	        nfiles = 1
	        dnfiles = 0
	        dndirs = 1
	        oi = <value optimized out>
	        ac = <value optimized out>
	        i = <value optimized out>
	        av = (char **) 0x80be674
	        tabstops_str = 0x0
	        terminal_width_str = 0x0
	        color_opt = 0x80be66c "<f\v\bLf\v\b\\f\v\b"
	        dotdir = {0x80b41fe "."}
	#3  0x08092d1b in tryexec (cmd=0xfe <Address 0xfe out of bounds>, argv=0x80c2fe8, envp=0x1) at shell/ash.c:3761
	        a = <value optimized out>
	        argc = <value optimized out>
	#4  0x08092dcb in shellexec (argv=0xfe,
	    path=0x80c2fe8 "12 15:19 \033[1;32mpppoe-discovery\033[0m\n-rwxr-xr-x    1 root     root         9912 Mar 12 15:19 \033[1;32mpppstats\033[0m\nlrwxrwxrwx    1 root     root", ' ' <repeats 12 times>, "7 Mar 14 08:49 \033[1;36mprintf\033[0m -> \033[1;32mbusy"..., idx=1) at shell/ash.c:3712
	        cmdname = <value optimized out>
	        e = <value optimized out>
	        envp = (char **) 0x80be67c
	        exerrno = <value optimized out>
	#5  0x080c4fe5 in ?? ()
	No symbol table info available.
	#6  0x080c4f08 in ?? ()
	No symbol table info available.
	#7  0x080be66c in stackbase ()
	No symbol table info available.
	#8  0x00000000 in ?? ()
	No symbol table info available.
	
	It seems that show_files is at line 430 and list_single is inlined.
	
	I also tried with valgrind. No problems reported. And it does not segfault, either.
	 
	I also made a binary that is compiled with -O0 (no optimization). It failed myteriously thus:
	(gdb) bt full
	#0  0x0805891a in openvt_main (argc=804208, argv=0xb7f95ae0) at console-tools/openvt.c:35
	        fd = 0
	        vtname = "\b\001\000\000\000ÿ\000\000\000¡\000\000"
	#1  0x00000000 in ?? ()
	This binary also works succesfully with valgrind. And without -l.
	 
	Where to continue from here?
	Anybody with more knowledge of the internals of busybox with suggestions to try?
	 
	Thanks,
	Jan Evert 
 
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