[Ltrace-devel] Couldn't determine base address of linux-vdso32.so.1. Harmless?

Randy MacLeod rwmacleod at gmail.com
Mon Nov 26 06:19:08 UTC 2012


Hi,

I see an apparently harmless but annoying log that Andreas mentioned on the
0.70 announcement (Nov 12th was the last comment). Has that been resolved?

# ltrace echo a
Couldn't determine base address of linux-vdso32.so.1
Couldn't load ELF object linux-vdso32.so.1: No such file or directory
__libc_start_main(2, 0xbfe1ec84, 0xbfe1ec90, 0xbfe1ecc4 <unfinished ...>
getenv("POSIXLY_CORRECT")                        = nil
strrchr("echo", '/')                             = nil
...
ltrace works well otherwise.
My kernel is 3.4, gcc is 4.6 and I'm cross-compiling.

I'm using git head (4fb13f6aa2eb371a724e2e02e744cf993ddea8f2) using a
bitbake recipe
for Yoctoproject.org/ OE-core and the simple bitbake recipe attached.
This happens for x86 and ppc, iirc. I'll investigate more tomorrow
but any tips would be appreciated.

root at qemu0:~# ldd /bin/echo
        linux-vdso32.so.1 (0x00100000)
        libc.so.6 => /lib/libc.so.6 (0x0fe50000)
        /lib/ld.so.1 (0x0ffd0000)


Enabling some ltrace --debug 077 echo a
DEBUG: dict.c:98: dict_enter()
DEBUG: dict.c:124: new dict entry at 0x10084930[914]: (0xffdfce0,0x1005b380)
DEBUG: breakpoint.c:85: enable_breakpoint: pid=431, addr=0xffdfce0,
symbol=(null
)
DEBUG: breakpoint.c:48: arch_enable_breakpoint: pid=431, addr=0xffdfce0,
symbol=
(null)
DEBUG: proc.c:474: crawl_linkmap()
Couldn't determine base address of linux-vdso32.so.1
Couldn't load ELF object linux-vdso32.so.1: No such file or directory
DEBUG: ltrace-elf.c:342: do_init_elf(filename=/lib/libc.so.6)


If I strace ltrace echo a


ptrace(PTRACE_PEEKTEXT, 438, 0xfff1ff8, [0]) = 0
ptrace(PTRACE_PEEKTEXT, 438, 0xfff1ffc, [0]) = 0
ptrace(PTRACE_PEEKTEXT, 438, 0xfff2000, [0]) = -1 EIO (Input/output error)
open("linux-vdso32.so.1", O_RDONLY)     = -1 ENOENT (No such file or
directory)
write(2, "Couldn't determine base address "..., 53) = 53
write(2, "Couldn't load ELF object linux-v"..., 70) = 70

That doesn't really help but it was fun and interesting to note that it
actually worked.

-- 
../Randy/..
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