bad/missing unwind information, which could result in libunwind
dereferencing bad pointers. This mechanism is based on msync(2) system
call and significantly reduces the chances of a bad pointer
dereference in libunwind.
The original idea was to turn this mechanism on only when necessary
i.e. libunwind didn't find proper unwind information for a IP.
There are a couple of problems in the current implementation.
* The flag is global and is modified without locking
* The flag isn't reset when starting a new unwind
The attached patch makes ->validate a per-thread setting by moving it
into struct cursor from unw_local_addr_space and resets it to false
when starting a new unwind. As a result, cursor->as_arg points to the
cursor itself instead of the ucontext (for the local case).
This was found to reduce the number of msync() system calls from an
application using libunwind significantly.
Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
Signed-off-by: Arun Sharma <arun.sharma@google.com>
* src/arm/unwind_i (arm_lock, arm_local_resume): Define.
* src/ptrace/_UPT_find_proc_info.c: Handle ARM like X86 etc.
* tests/flush-cache.S (flush_cache): Add (dummy) ARM-version.
ARM does need executable stack, even on Linux...
Signed-off-by: Anderson Lizardo <anderson.lizardo@indt.org.br>
Signed-off-by: Bruna Moreira <bruna.moreira@indt.org.br>
- Gtest-bt: like on x86/-64, the stack size passed to sigaltstack() is
too small for ARM thus causing segmentation fault due to stack
overflow.
- Gtest-dyn1: code size definition of dynamic function (template()) on
testcase is too big for ARM architecture so memcpy() reads invalid
memory causing random crashes (segmentation fault). A better
solution would be to compile the function in a separate binary,
mmap() it and memcpy() from it instead, so maximum size is known for
sure.
- check-name-space.in: fix some "bashisms", it causes the script to
fail to run on N8XX's busybox shell.
Signed-off-by: Anderson Lizardo <anderson.lizardo@indt.org.br>
Signed-off-by: Bruna Moreira <bruna.moreira@indt.org.br>
The current pattern is too restrictive and doesn't work well on
modern glibcs.
Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
Signed-off-by: Arun Sharma <arun.sharma@google.com>
* Use explicit types for XMM registers
* Support full width (128 bits) access
Signed-off-by: Andrew Cagney <cagney@redhat.com>
Signed-off-by: Arun Sharma <aruns@google.com>
as "weak". Since the elf-support is in the library anyhow, this serves
no purpose and in fact causes problem because the weak reference alone
is not enough to pull in the ELF-code from an archive file, causing to
spurious failures of get_proc_name.
On some systems executable stacks are denied. Since libunwind and the
tests don't actually need executable stacks this patch marks all
assembly files as not needing it.
The original patch comes from frysk:
2007-04-05 Jan Kratochvil <jan.kratochvil@redhat.com>
* src/hppa/getcontext.S, src/hppa/setcontext.S, src/hppa/siglongjmp.S,
src/ia64/Ginstall_cursor.S, src/ia64/Linstall_cursor.S,
src/ia64/dyn_info_list.S, src/ia64/getcontext.S, src/ia64/longjmp.S,
src/ia64/setjmp.S, src/ia64/siglongjmp.S, src/ia64/sigsetjmp.S,
src/ppc64/longjmp.S, src/ppc64/siglongjmp.S, src/x86/longjmp.S,
src/x86/siglongjmp.S, src/x86_64/longjmp.S, src/x86_64/setcontext.S,
src/x86_64/siglongjmp.S: Stack should be non-executable, for SELinux.
I added a couple more markers for new files in current libunwind.
Before this patch you would get the following on selinux enabled
systems without allow_exec_stack: error while loading shared
libraries:
libunwind.so.7: cannot enable executable stack as shared object
requires: Permission denied
After the patch that error disappears and all test results are similar
to the results on systems without executable stack protection.
routine and add address-space argument. This is needed because on
PPC64, a the function-name symbol refers to a function descriptor
(unlike, for example, on ia64, where the @fptr() operator is needed to
refer to a function descriptor). Thus, in order to look up the name
of a function, we need to dereference the function descriptor. To
make matters more "interesting", the function descriptors are normally
resolved by the dynamic linker, so we can't get their values from the
ELF file. Instead, we have to read them from the running image, hence
the need for the address-space argument.
* tests/ia64-test-setjmp.c (doit): New forward declaration.
(doit_pointer): New function pointer variable initialized to DOIT.
(doit): Self-call made by an unoptimizable volatile indirect call.
* tests/test-ptrace.c (target_pid_kill): New function.
(target_pid, main): TARGET_PID made static, for target_pid_kill ().
(main): Register target_pid_kill () for atexit(3).
2007-04-04 Jan Kratochvil <jan.kratochvil@redhat.com>
* tests/Gtest-dyn1.c, tests/test-async-sig.c, tests/test-ptrace.c:
Fixed lockups on broken libunwind (as ppc64 is).
2007-03-07 Jan Kratochvil <jan.kratochvil@redhat.com>
* tests/test-async-sig.c (do_backtrace): Limit maximum backtrace depth
to 100 iterations; it workarounds FC6 DWARF-broken glibc.
2006-12-10 Jan Kratochvil <jan.kratochvil@redhat.com>
* tests/test-ptrace.c (main): Check for too many unexpected child
signals, such as the common `SIGSEGV'.
