Just pass potentially NULL pointers to free() in the error path in
load_debug_frame(). Saved 40 bytes of code in libunwind.so on ARM -O2
thumb build at the expense of slightly slower execution.
Stop pretending that unw_get_proc_info() works on PPC, and instead give
an error back to the caller. As far as I can tell, none of the libunwind
tests clear out the `unw_proc_info_t' before passing it to
unw_get_proc_info(), so they would end up working on garbage data.
ppc32/Gstep.c:116: warning: comparison between pointer and integer
ppc32/Gstep.c:116: warning: comparison with string literal results in unspecified behavior
ppc32/Gstep.c:116: warning: initialization makes integer from pointer without a cast
ppc32/Gstep.c:116: warning: passing argument 2 of 'fprintf' makes pointer from integer without a cast
/usr/powerpc-linux-gnu/include/stdio.h:333: note: expected 'const char *__restrict__' but argument is of type 'int'
Fix bitrot in HPPA common_init(). This has only been compile tested.
hppa/init.h: In function 'common_init':
hppa/init.h:33: error: 'struct cursor' has no member named 'ip_loc'
hppa/init.h:33: warning: implicit declaration of function 'HPPA_REG_LOC'
hppa/init.h:34: error: 'struct cursor' has no member named 'sp_loc'
hppa/init.h:36: warning: implicit declaration of function 'hppa_get'
hppa/init.h:36: error: 'struct cursor' has no member named 'ip_loc'
hppa/init.h:36: error: 'struct cursor' has no member named 'ip'
hppa/init.h:40: error: 'struct cursor' has no member named 'sp'
When cross-compiling libunwind with optimizations (-O1 or higher),
gcc-4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) optimizes away the memory
writes prior to the inline asm() statement in arm_local_resume() in the
non-signal-frame path, causing the `regs' array to be only allocated on
the stack, but not populated. This means that we are restoring garbage
to the registers.
As suggested in the GCC docs, add a fixed size input memory constraint
for the array content. This is enough to get the desired code to be
generated.
Adding __builtin_unreachable() to the point that we should never reach
was also in itself enough to inhibit the optimization. It also reduces
the function size by a few instructions.
Check the endianness earlier in unw_create_addr_space() on all
architectures to avoid leaking the dynamically allocated address space
struct.
This was already fixed for ARM in commit cf6a998796 ("Fix memory leak
in ARM unw_create_addr_space()"). Move the endianness check also on ARM
to avoid malloc() & free() in the error case.
Properly export the symbol names also on MIPS. `make check' was
complaining:
src/.libs/libunwind.a(Linit.o): In function `mips_local_addr_space_init':
src/mips/Ginit.c:183: multiple definition of `mips_local_addr_space_init'
../src/.libs/libunwind-mips.a(Ginit.o):src/mips/Ginit.c:183: first defined here
src/.libs/libunwind.a(Lglobal.o): In function `_ULmips_init':
src/mips/Gglobal.c:42: multiple definition of `mips_lock'
../src/.libs/libunwind-mips.a(Gglobal.o):src/mips/Gglobal.c:42: first defined here
collect2: ld returned 1 exit status
After searching the normal symbol table, look if the binary contains
.gnu_debugdata section. If it does, run LZMA decompression on it, load
the resulting ELF image into memory and call lookup_symbol() on it
again.
lookup_symbol() is modified so that it takes min_dist as a parameter and
only returns a symbol when it finds one that is closer than indicated by
the parameter.
Signed-off-by: Martin Milata <mmilata@redhat.com>
The code for symbol lookup (elfxx.c:lookup_symbol) works by iterating
over symbol tables while maintaing the symbol closest to the supplied
instruction pointer. Whenever this search encountered symbol that was
longer than result buffer, the function returned -UNW_ENOMEM even though
the final symbol wasn't too long.
Signed-off-by: Martin Milata <mmilata@redhat.com>
dwarf/Gfind_unwind_table.c: In function '_Ux86_dwarf_find_unwind_table':
dwarf/Gfind_unwind_table.c:223:46: error: 'struct elf_dyn_info' has no member named 'edi'
Fixup commit d93d96ad83 ("Fix compilation
on IA64"), and replace the dwarf_find_unwind_table() call with
tdep_find_unwind_table().
Fixes linkage error on IA64:
../src/.libs/libunwind-coredump.so: undefined reference to `dwarf_find_unwind_table'
Change the way we generate the cursor header files, so that we do not
need to invoke IA64 binaries, which would fail when cross-compiling
libunwind.
Adopt the strategy used in the Linux kernel build system, and parse our
annotated offset information from the assembler file produced by the
compiler.
- Add tdep macro for {dwarf,ia64}_find_unwind_table so that ia64
doesn't try to use dwarf code.
- Fix extraneous #if.
- Fix mistyped filename in Makefile.am.
- Link ia64-specific tests with correct libraries.
Signed-off-by: Martin Milata <mmilata@redhat.com>
This reverts commit c9c5a40be1.
dwarf_get() returns 0 on success. We should continue unwinding
in that case.
TBD: investigate test-ptrace failure on some platforms.
If dwarf_get returns 0 (indicating the end of call chain), we should
not override the return value to 1. This may result in the caller
continuing to unwind and getting spurious errors.
In the commit d04dc94cc2, the check for
dwarf.ip == 0 was removed from non-dwarf walker in x86_64 version of
unw_step(). Apparently this broke the detection of the end of frame
chain when NULL %rbp is specified, because the case just marked
dwarf.ip as 0. Explicitly set ret to 0 to indicate the end of
iteration.
Older kernels interpret the pid argument of the process information
sysctls as pid only. If libunwind UPT consumer passed tid to _UPT_create,
tdep_get_elf_image() returns error due to sysctls failure. Provide a
slow workaround by searching for a process owning the supplied tid if
sysctl returned ESRCH.
Currently the expression evaluation always succeeds,
and possible error is not propagated to the caller.
The ',' operator makes the condition always return 0.
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Paul Pluzhnikov <ppluzhnikov@google.com>
ALIGN lets you align pointers and STRUCT_MEMBER lets you get
structure members at a specific offset.
These are useful in general, and will be needed for the coredump notes
cleanup work.
These let you get the pid and the current signal from the coredump.
This isn't strictly unwind related, but these are trivial to implement
as we have the info, and you almost always want these when you're
printing a backtrace from a core file.
Move ptrace-independent code from src/ptrace/_UPT_find_proc_info.c
to src/dwarf/{G,L}find_unwind_table.c. Name this moved function
dwarf_find_unwind_table().
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This is a common part of struct UPT_info
and struct UCD_info (to be introduced later).
Make _UPTi_find_unwind_table function operate only on this part
of struct UPT_info.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Commit 7d43108f9c ("No
libunwind-generic.so if configured with --disable-shared") introduced a
check to avoid creating a broken libunwind-generic.so link, but the
result of the commit is that libunwind-generic.so is never created (at
least when installing to a clean directory).
We need to check for the installed libunwind-$(arch).so file,
libunwind-generic.so will be the symbolic link name.
There is a window of time between the munmap and the tls_cache being
marked as destroyed, where there could be a bad access to memory that
has been unmapped/freed. Reorder the code a bit to close the window.
Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
Commit 297d9cd07d (Fix for failing test-setjmp)
breaks non glibc systems, since __GLIBC_PREREQ is not defined there.
As a consequence, preprocessor aborts with an error.
Trying to hide __GLIBC_PREREQ under #ifdef __GLIBC would require
either code duplication, or moving the longjmp implementation into
the separate file, which is included twice. In fact, I am not sure
in any use of the __GLIBC_PREREQ at the compile time, because the
compiled code can be run on the later version of glibc.
Below is the patch, tested on FreeBSD x86/x86_64 and Scientific Linux 6.1
x86_64. I compile the code always, but keep it in under unused static
symbol. In principle, the code could be optimized out by linker.
[ Minor formatting edits: asharma@fb.com ]
The crashes were tracked down to f->rpb_cfa_offset being incorrect.
The problem is that {rsp,rbp}_cfa_offset only have 15 bits, but for
SIGRETURN frame they are filled with:
// src/x86_64/Gstash_frame.c
f->cfa_reg_offset = d->cfa - c->sigcontext_addr;
f->rbp_cfa_offset = DWARF_GET_LOC(d->loc[RBP]) - d->cfa;
f->rsp_cfa_offset = DWARF_GET_LOC(d->loc[RSP]) - d->cfa;
The problem is that the delta here can be arbitrarily large when
sigaltstack is used, and can easily overflow the 15 and 30-bit fields.
When signal handler starts running, the stack layout is:
... higher addresses ...
ucontext
CFA->
__restore_rt (== pretcode in rt_sigframe from
linux-2.6/arch/x86/include/asm/sigframe.h)
SP ->
... sighandler runs on this stack.
... lower addresses ...
This makes it very convenient to find ucontext from the CFA.
Attached patch re-tested on Linux/x86_64, no new failures.
Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
Reviwed-by: Lassi Tuura <lat@cern.ch>
On Mon, Nov 14, 2011 at 5:02 PM, Paul Pluzhnikov <ppluzhnikov@google.com> wrote:
> P.S. test-setjmp is failing for me (before or after the patch).
> When I enable assertions (to confirm my new assertions are correct), I see:
>
> lt-test-setjmp: ../../src/dwarf/Gparser.c:754: apply_reg_state: \
> Assertion `rs->reg[17].where == DWARF_WHERE_EXPR' failed.
>
> which likely explains that failure.
The problem is actually two-fold:
First, the loops in {sig,}longjmp.c are "do { ... } while (unw_step() >= 0);"
But unw_step() returns 0 on reaching the end of the chain (_start),
and the loop should stop there.
The second problem is that with this commit:
c67da0b50e
glibc obfuscates value of SP in jmp_buf, so we might as well just give up.
Patch attached.
Thanks,
--
Paul Pluzhnikov
The ARM EABI does not use the .eh_frame and .eh_frame_hdr sections for unwinding. Therefore it doesn't make sense to call dwarf_step if CONFIG_DEBUG_FRAME is not defined.
Define unw_tdep_context rather than using ucontext_t in order to support
systems that lack ucontext.h. Note that POSIX.1-2008 removed getcontext,
makecontext and swapcontext from its specification.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Since the dl_iterate_phdr is required for local unwinding only the use of
struct dl_phdr_info can be eliminated in case libunwind gets compiled for
remote unwinding. This enhances libunwinds portability to targets that
don't provide any dl_iterate_phdr functionality.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Exclude <link.h> because it is only required for local unwinding when
iterating over the program headers.
Have the following DWARF related functions available in case of
UNW_REMOTE_ONLY because they are used by libunwind-ptrace:
dwarf_find_debug_frame
locate_debug_info
find_binary_for_address
load_debug_frame
debug_frame_tab_new
debug_frame_tab_append
debug_frame_tab_shrink
debug_frame_tab_compare
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Glibc calls thread-specific dtors in the order in which the keys were added,
so the first dtor is the trace_cache_free() one. Then thread-specific
data for some other key is free()d, which calls into unw_backtrace(),
which uses dangling cache and munmapped cache->frames.
[ Minor rename + compiler warning fix: asharma@fb.com ]
Signed-off-by: Paul Pluzhnikov <ppluzhnikov@google.com>
On FreeBSD, as well as on the Solaris < 10, weak pthread_once stub is
always exported from libc. But it does nothing, which means that if
threaded library is not loaded, then pthread_once() call do not actually
call the initializer finction. The construct
if (likely (pthread_once != 0))
{
pthread_once(&trace_cache_once, &trace_cache_init_once);
then fails to initialize the trace cache on x86_64.
Work around by checking that the initializer was indeed called.
Note that this can break if libthr is loaded dynamically, but my belief
is that there is no platforms which allow dynamic loading of the threading
library.
This keeps the definition on IA64 and all the other architectures in sync with
the declaration of _UPTi_find_unwind_table. This also mimics the behaviour of
what's done for local unwinding and allows the function to provide more than
one way to undwind.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
In case the user doesn't specify whether to unwind using the ARM specific
unwind tabler or DWARF info libunwind should prefer the latter. Since DWARF
expressions are more powerful than the ARM specific unwind tables
arm_find_proc_info is changed to check for DWARF first.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Prevents unw_step from trying to unwind the stack using the ARM specific
unwind tables in case the DWARF based unwinding was successful.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Initialize the return value with -1 in order prevent arm_find_proc_info from
returning zero. This could happen in case the environemtn variable
UNW_ARM_UNWIND_METHOD doesn't allow exidx and/or dwarf unwinding.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Change _UPTi_find_unwind_table to also look for the ARM specific unwind
information. Adjust the ARM unwind code to read memory using the accessor
routines.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
Rename the dwarf dl_iterate_phdr callback routine and the callback_data
structure to dwarf_callback and dwarf_callback_data. Make it available
within libunwind by declaring the two at the dwarf.h header file.
Signed-off-by: Ken Werner <ken.werner@linaro.org>
