TLS_INIT_TP in sysdeps/i386/nptl/tls.h uses some hand written asm to
generate a set_thread_area that might result in exchanging ebx and esp
around the syscall causing introspection tools like valgrind to loose
track of the user stack. Just use INTERNAL_SYSCALL which makes sure
esp isn't changed arbitrarily.
Before the patch the code would generate:
mov $0xf3,%eax
movl $0xfffff,0x8(%esp)
movl $0x51,0xc(%esp)
xchg %esp,%ebx
int $0x80
xchg %esp,%ebx
Using INTERNAL_SYSCALL instead will generate:
movl $0xfffff,0x8(%esp)
movl $0x51,0xc(%esp)
xchg %ecx,%ebx
mov $0xf3,%eax
int $0x80
xchg %ecx,%ebx
Thanks to Florian Weimer for analysing why the original code generated
the bogus esp usage:
_segdescr.desc happens to be at the top of the stack, so its address
is in %esp. The asm statement says that %3 is an input, so its value
will not change, and GCC can use %esp as the input register for the
expression &_segdescr.desc. But the constraints do not fully describe
the asm statement because the %3 register is actually modified, albeit
only temporarily.
[BZ #17319]
* sysdeps/i386/nptl/tls.h (TLS_INIT_TP): Use INTERNAL_SYSCALL
to call set_thread_area instead of hand written asm.
(__NR_set_thread_area): Removed define.
(TLS_FLAG_WRITABLE): Likewise.
(__ASSUME_SET_THREAD_AREA): Remove check.
(TLS_EBX_ARG): Remove define.
(TLS_LOAD_EBX): Likewise.
This directory contains the sources of the GNU C Library.
See the file "version.h" for what release version you have.
The GNU C Library is the standard system C library for all GNU systems,
and is an important part of what makes up a GNU system. It provides the
system API for all programs written in C and C-compatible languages such
as C++ and Objective C; the runtime facilities of other programming
languages use the C library to access the underlying operating system.
In GNU/Linux systems, the C library works with the Linux kernel to
implement the operating system behavior seen by user applications.
In GNU/Hurd systems, it works with a microkernel and Hurd servers.
The GNU C Library implements much of the POSIX.1 functionality in the
GNU/Hurd system, using configurations i[4567]86-*-gnu. The current
GNU/Hurd support requires out-of-tree patches that will eventually be
incorporated into an official GNU C Library release.
When working with Linux kernels, this version of the GNU C Library
requires Linux kernel version 2.6.32 or later.
Also note that the shared version of the libgcc_s library must be
installed for the pthread library to work correctly.
The GNU C Library supports these configurations for using Linux kernels:
aarch64*-*-linux-gnu
alpha*-*-linux-gnu
arm-*-linux-gnueabi
hppa-*-linux-gnu Not currently functional without patches.
i[4567]86-*-linux-gnu
x86_64-*-linux-gnu Can build either x86_64 or x32
ia64-*-linux-gnu
m68k-*-linux-gnu
microblaze*-*-linux-gnu
mips-*-linux-gnu
mips64-*-linux-gnu
powerpc-*-linux-gnu Hardware or software floating point, BE only.
powerpc64*-*-linux-gnu Big-endian and little-endian.
s390-*-linux-gnu
s390x-*-linux-gnu
sh[34]-*-linux-gnu
sparc*-*-linux-gnu
sparc64*-*-linux-gnu
tilegx-*-linux-gnu
tilepro-*-linux-gnu
If you are interested in doing a port, please contact the glibc
maintainers; see http://www.gnu.org/software/libc/ for more
information.
See the file INSTALL to find out how to configure, build, and install
the GNU C Library. You might also consider reading the WWW pages for
the C library at http://www.gnu.org/software/libc/.
The GNU C Library is (almost) completely documented by the Texinfo manual
found in the `manual/' subdirectory. The manual is still being updated
and contains some known errors and omissions; we regret that we do not
have the resources to work on the manual as much as we would like. For
corrections to the manual, please file a bug in the `manual' component,
following the bug-reporting instructions below. Please be sure to check
the manual in the current development sources to see if your problem has
already been corrected.
Please see http://www.gnu.org/software/libc/bugs.html for bug reporting
information. We are now using the Bugzilla system to track all bug reports.
This web page gives detailed information on how to report bugs properly.
The GNU C Library is free software. See the file COPYING.LIB for copying
conditions, and LICENSES for notices about a few contributions that require
these additional notices to be distributed. License copyright years may be
listed using range notation, e.g., 2000-2013, indicating that every year in
the range, inclusive, is a copyrightable year that would otherwise be listed
individually.
9570bc53fc