Date: Tue, 29 Nov 2011 08:43:02 GMT From: Rune <u-uclibc-y2lt@aetey.se> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/162943: uClibc explicit runtime loader segfaults under FreeBSD's Linux ABI Message-ID: <201111290843.pAT8h2Nu024155@red.freebsd.org> Resent-Message-ID: <201111290850.pAT8oBrA064251@freefall.freebsd.org>
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>Number: 162943
>Category: kern
>Synopsis: uClibc explicit runtime loader segfaults under FreeBSD's Linux ABI
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Nov 29 08:50:11 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator: Rune
>Release: 8.1, 9.0-RC2
>Organization:
>Environment:
varied between the machines, the kernels tested were at least both 8.1 of Debian/kFreeBSD and 9.0-RC2 from PC-BSD
>Description:
ld-uClibc.so.0 can be run and provides the expected diagnostics
("chances are you did not intend to run me")
Running programs using the hardcoded implicit dynamic loader works too.
Running "ld-uClibc.so.0 <binary>" segfaults quite early, before
accessing any other files than the <binary>.
uClibc is from git around 2011-09-15, it reports itself
as 0.9.33-git. The tests were done with FreeBSD 8.1 (Debian kFreeBSD)
and 9.0-RC2 (FreeBSD), with the same result.
The library is configured and compiled for Linux 2.4.19.
No problems detected running on various Linux kernels (2.6.x).
Strace output on Linux (ktrace from FreeBSD done and compared but not preserved)
Comparing strace on Linux and ktrace on FreeBSD (omitted) output
while trying to run "ar" from gnu binutils, compiled and linked with uClibc:
-----------------------------------------------------------------------------
execve("/.../ld-uClibc.so.0", ["/.../ld-uClibc.so.0", "/.../ar"], .......
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|0x4000000, -1,
0) = 0xb7f7c000
open("/.../ar", O_RDONLY) = 3
fstat(3, {st_dev=makedev(3, 1), st_ino=613642, st_mode=S_IFREG|0555, st_nlink=1,
st_uid=2001, st_gid=2001, st_blksize=4096, st_blocks=936, st_size=471140, st_at
ime=2011/11/21-16:33:34, st_mtime=2011/11/19-21:47:37, st_ctime=2011/11/19-21:47
:38}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS|0x4000000, -1,
0) = 0xb7f7b000
read(3, "\177ELF\1\1\1\3\0\0\0\0\0\0\0\0\2\0\3\0\1\0\0\0p\226\4\0104\0\0\0\314,\
7\0\0\0\0\0004\0 \0\7\0(\0\27\0\26\0\6\0\0\0004\0\0\0004\200\4\0104\200\4\10\340
\0\0\0\340\0\0\0\5\0\0\0\4\0\0\0\3\0\0\0\24\1\0\0\24\201\4\10\24\201\4\10\37\0\0
\0\37\0\0\0\4\0\0\0\1\0\0\0\1\0\0\0\0\0\0\0\0\200\4\10\0\200\4\10T\27\7\0T\27\7\
0\5\0\0\0\0\20\0\0\1\0\0\0\0 \7\0\0\240\v\10\0\240\v\10P\6\0\0\334I\0\0\6\0\0\0"
.., 4096) = 4096
mmap2(0x8048000, 487424, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x804800
0
mmap2(0x8048000, 464724, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0x8
048000
mmap2(0x80ba000, 1616, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x72) = 0
x80ba000
mmap2(0x80bb000, 14812, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOU
S, -1, 0) = 0x80bb000
=====> Segfault under FreeBSD happens here, before/instead of close() <======
close(3) = 0
...
-----------------------------------------------------------------------------
>How-To-Repeat:
Compile uClibc on Linux with support for dynamic linking and explicit runtime loader.
Run uClibc runtime loader with a binary (dynamically linked with uClibc) as the argument.
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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