A subsequent patch will make the Linux backend's target_wait method
pull all events out of the kernel (with waitpid) and store them as
pending status in the LWP structure if no pending status was already
available. Then, the backend goes over the pending statuses and pick
one to report to the core.
With that, the existing thread-execl.exp test exposes a bug, like:
(gdb) set scheduler-locking on
(gdb) PASS: gdb.threads/thread-execl.exp: schedlock on: set scheduler-locking on
next
FAIL: gdb.threads/thread-execl.exp: schedlock on: get to main in new image (timeout)
Recall that when the non-leader thread execs, all threads in the
process die, the execing thread changes its pid to the tgid, and then
waitpid returns an exec event to the tgid. If GDB didn't resume the
leader LWP, then GDB sees an event for an LWP that was supposedly
stopped, and thus not marked as resumed. Because the code that picks
a pending event to report to the core ignores not-resumed LWPs:
/* Return non-zero if LP has a wait status pending. */
static int
status_callback (struct lwp_info *lp, void *data)
{
/* Only report a pending wait status if we pretend that this has
indeed been resumed. */
if (!lp->resumed)
return 0;
the event ends up pending forever, thus the timeout.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_handle_extended_wait) <PTRACE_EVENT_EXEC>:
Set the LWP's 'resumed' flag.
Whenever we resume an LWP, we must clear a few flags and flush the
LWP's register cache. We actually currently flush the register cache
of all LWPs, but that's unnecessary. This patch makes us flush the
register cache of only the LWP that is resumed. Instead of open
coding all that in many places, we use a helper function.
Likewise, we have two fields in the LWP structure where a pending
status may be recorded. Add a helper predicate that checks both and
use it throughout instead of open coding the checks.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_resume_one_lwp): New function.
(resume_lwp): Use lwp_status_pending_p and linux_resume_one_lwp.
(linux_nat_resume): Use lwp_status_pending_p and
linux_resume_one_lwp.
(linux_handle_syscall_trap): Use linux_resume_one_lwp.
(linux_handle_extended_wait): Use linux_resume_one_lwp.
(status_callback, running_callback): Use lwp_status_pending_p.
(lwp_status_pending_p): New function.
(stop_and_resume_callback): Use lwp_status_pending_p.
(linux_nat_filter_event): Use linux_resume_one_lwp.
(linux_nat_wait_1): Always use status_callback to look for an LWP
with a pending status. Use linux_resume_one_lwp.
(resume_stopped_resumed_lwps): Use lwp_status_pending_p and
linux_resume_one_lwp.
Factor out common code, and use the more efficient
ALL_BP_LOCATIONS_AT_ADDR.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* breakpoint.c (bp_location_inserted_here_p): New function,
factored out from ...
(breakpoint_inserted_here_p): ... here. Use
ALL_BP_LOCATIONS_AT_ADDR.
(software_breakpoint_inserted_here_p): Use
bp_location_inserted_here_p and ALL_BP_LOCATIONS_AT_ADDR.
This patch fixes the watch_thread_num.exp test to work when the target
is better at making event handling be fair among threads.
I wrote patches that make GDB native and GDBserver event handling
fairer between threads. That is, if threads A and B both
simultaneously trigger some debug event, GDB will pick either A or B
at random, rather than always handling the event of A first. There's
code for that in the Linux backends (gdb and gdbserver) already, but
it can be improved, and only works in all-stop mode.
With those fixes in place, I found that the watch_thread_num.exp would
often time out. The problem is that the test only works _because_
event handling isn't as fair as intended. With the fairness fixes,
the test falls victim of PR10116 (gdb drops watchpoints on
multi-threaded apps) quite often.
To expand on the PR10116 reference, consider that stop events are
serialized to GDB core, through target_wait. Say a thread-specific
watchpoint as set on thread A. When the "right" thread and some other
"wrong" thread both trigger a watchpoint simultaneously, the target
may report the "wrong" thread's hit to GDB first (thread B). When
handling that event, GDB notices the watchpoint is for another thread,
and so shouldn't cause a user-visible stop. On resume, GDB saves the
now current value of the watched expression. Afterwards, the "right"
thread (thread A) reports its watchpoint trigger. But the watched
value hasn't changed since GDB last saved it, and so GDB doesn't
report the watchpoint hit to the user.
The way the test is written, the watchpoint is associated with the
first thread that happens to report an event. It happens that GDB is
processing events much more often for one of the threads, which
usually will be that same first thread.
Hacking the test with "set debug infrun 1", we see exactly that:
$ grep "infrun.*\[Thread.*," testsuite/gdb.log | sort | uniq -c | sort -nr
70 infrun: 8798 [Thread 8798],
37 infrun: 8798 [Thread 8802],
36 infrun: 8798 [Thread 8804],
36 infrun: 8798 [Thread 8803],
35 infrun: 8798 [Thread 8805],
34 infrun: 8798 [Thread 8806],
The first column shows the number of times the target reported an
event for that thread, from:
infrun: target_wait (-1, status) =
infrun: 8798 [Thread 8798],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
This masks out the PR10116 issue.
However, if the target is better at giving equal priority to all
threads, the PR10116 issue happens often, so it may take quite a while
for the right thread to be the first to report its watchpoint event
just after the memory being watched really changed, resulting in test
time outs.
Here's the number of events handled for each thread on a gdbserver run
with the event fairness patches:
$ grep "infrun.*\[Thread.*," gdb.log | sort | uniq -c
2961 infrun: 13591 [Thread 13591],
2956 infrun: 13591 [Thread 13595],
2941 infrun: 13591 [Thread 13596],
2932 infrun: 13591 [Thread 13597],
2905 infrun: 13591 [Thread 13598],
2891 infrun: 13591 [Thread 13599],
Note how the number of events is much higher. The test routinely
takes over 10 seconds to finish on my machine rather than under a
second as with unpatched gdbserver, when it succeeds, but often it'll
fail with timeouts too.
So to make the test robust, this patch switches the tests to using
"awatch" instead of "watch", as access watchpoints don't care about
the watchpoint's "old value". With this, the test always finishes
quickly, and we can even bump the number of threads concurrently
writting to the shared variable, to have better assurance we're really
testing the case of the "wrong" thread triggering a watchpoint.
Here's the number of events I see for each thread on a run on my
machine, with a gdbserver patched with the event fairness series:
$ grep "infrun.*\[Thread.*," testsuite/gdb.log | sort | uniq -c
5 infrun: 5298 [Thread 5302],
4 infrun: 5298 [Thread 5303],
4 infrun: 5298 [Thread 5304],
4 infrun: 5298 [Thread 5305],
4 infrun: 5298 [Thread 5306],
4 infrun: 5298 [Thread 5307],
4 infrun: 5298 [Thread 5308],
4 infrun: 5298 [Thread 5309],
4 infrun: 5298 [Thread 5310],
4 infrun: 5298 [Thread 5311],
4 infrun: 5298 [Thread 5312],
4 infrun: 5298 [Thread 5313],
4 infrun: 5298 [Thread 5314],
4 infrun: 5298 [Thread 5315],
4 infrun: 5298 [Thread 5316],
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* gdb.base/annota1.exp (thread_test): Use srcfile and binfile from
the global scope. Set a breakpoint after all threads are started
rather than stepping over two source lines. Expect the prompt.
* gdb.base/watch_thread_num.c (threads_started_barrier): New
global.
(NUM): Now 15.
(main): Use threads_started_barrier to wait for all threads to
start. Main thread no longer calls thread_function. Exit after
180 seconds.
(loop): New function.
(thread_function): Wait on threads_started_barrier barrier. Call
'loop' at each iteration.
* gdb.base/watch_thread_num.exp: Continue to breakpoint after all
threads have started, instead of hardcoding number of "next"
steps. Use an access watchpoint instead of a write watchpoint.
These three test all spawn a few threads and then send a SIGSTOP to
their parent GDB in order to pause it while the new threads set things
up for the test. With a GDB patch that changes the inferior thread's
scheduling a bit, I sometimes see:
FAIL: gdb.threads/siginfo-threads.exp: catch signal 0 (timeout)
...
FAIL: gdb.threads/watchthreads-reorder.exp: reorder1: continue a (timeout)
...
FAIL: gdb.threads/ia64-sigill.exp: continue (timeout)
...
The issue is that the test program stops GDB before it had a chance of
processing the new thread's clone event:
(gdb) PASS: gdb.threads/siginfo-threads.exp: get pid
continue
Continuing.
Stopping GDB PID 21541.
Waiting till the threads initialize their TIDs.
FAIL: gdb.threads/siginfo-threads.exp: catch signal 0 (timeout)
On Linux (at least), new threads start stopped, and the debugger must
resume them. The fix is to make the test program wait for the new
threads to be running before stopping GDB.
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* gdb.threads/ia64-sigill.c (threads_started_barrier): New global.
(thread_func): Wait on barrier.
(main): Wait for all threads to start before stopping GDB.
* gdb.threads/siginfo-threads.c (threads_started_barrier): New
global.
(thread1_func, thread2_func): Wait on barrier.
(main): Wait for all threads to start before stopping GDB.
* gdb.threads/watchthreads-reorder.c (threads_started_barrier):
New global.
(thread1_func, thread2_func): Wait on barrier.
(main): Wait for all threads to start before stopping GDB.
Before the previous fixes, on Linux, this would trigger several
different problems, like:
[New LWP 27106]
[New LWP 27047]
warning: unable to open /proc file '/proc/-1/status'
[New LWP 27813]
[New LWP 27869]
warning: Can't attach LWP 11962: No child processes
Warning: couldn't activate thread debugging using libthread_db: Cannot find new threads: debugger service failed
warning: Unable to find libthread_db matching inferior's thread library, thread debugging will not be available.
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* gdb.threads/attach-many-short-lived-threads.c: New file.
* gdb.threads/attach-many-short-lived-threads.exp: New file.
[A test I wrote stumbled on a libthread_db issue related to thread
event breakpoints. See glibc PR17705:
[nptl_db: stale thread create/death events if debugger detaches]
https://sourceware.org/bugzilla/show_bug.cgi?id=17705
This patch avoids that whole issue by making GDB stop using thread
event breakpoints in the first place, which is good for other reasons
as well, anyway.]
Before PTRACE_EVENT_CLONE (Linux 2.6), the only way to learn about new
threads in the inferior (to attach to them) or to learn about thread
exit was to coordinate with the inferior's glibc/runtime, using
libthread_db. That works by putting a breakpoint at a magic address
which is called when a new thread is spawned, or when a thread is
about to exit. When that breakpoint is hit, all threads are stopped,
and then GDB coordinates with libthread_db to read data structures out
of the inferior to learn about what happened. Then the breakpoint is
single-stepped, and then all threads are re-resumed. This isn't very
efficient (stops all threads) and is more fragile (inferior's thread
list in memory may be corrupt; libthread_db bugs, etc.) than ideal.
When the kernel supports PTRACE_EVENT_CLONE (which we already make use
of), there's really no need to use libthread_db's event reporting
mechanism to learn about new LWPs. And if the kernel supports that,
then we learn about LWP exits through regular WIFEXITED wait statuses,
so no need for the death event breakpoint either.
GDBserver has been likewise skipping the thread_db events for a long
while:
https://sourceware.org/ml/gdb-patches/2007-10/msg00547.html
There's one user-visible difference: we'll no longer print about
threads being created and exiting while the program is running, like:
[Thread 0x7ffff7dbb700 (LWP 30670) exited]
[New Thread 0x7ffff7db3700 (LWP 30671)]
[Thread 0x7ffff7dd3700 (LWP 30667) exited]
[New Thread 0x7ffff7dab700 (LWP 30672)]
[Thread 0x7ffff7db3700 (LWP 30671) exited]
[Thread 0x7ffff7dcb700 (LWP 30668) exited]
This is exactly the same behavior as when debugging against remote
targets / gdbserver. I actually think that's a good thing (and as
such have listed this in the local/remote parity wiki page a while
ago), as the printing slows down the inferior. It's also a
distraction to keep bothering the user about short-lived threads that
she won't be able to interact with anyway. Instead, the user (and
frontend) will be informed about new threads that currently exist in
the program when the program next stops:
(gdb) c
...
* ctrl-c *
[New Thread 0x7ffff7963700 (LWP 7797)]
[New Thread 0x7ffff796b700 (LWP 7796)]
Program received signal SIGINT, Interrupt.
[Switching to Thread 0x7ffff796b700 (LWP 7796)]
clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:81
81 testq %rax,%rax
(gdb) info threads
A couple of tests had assumptions on GDB thread numbers that no longer
hold.
Tested on x86_64 Fedora 20.
gdb/
2014-01-09 Pedro Alves <palves@redhat.com>
Skip enabling event reporting if the kernel supports
PTRACE_EVENT_CLONE.
* linux-thread-db.c: Include "nat/linux-ptrace.h".
(thread_db_use_events): New function.
(try_thread_db_load_1): Check thread_db_use_events before enabling
event reporting.
(update_thread_state): New function.
(attach_thread): Use it. Check thread_db_use_events before
enabling event reporting.
(thread_db_detach): Check thread_db_use_events before disabling
event reporting.
(find_new_threads_callback): Check thread_db_use_events before
enabling event reporting. Update the thread's state if not using
libthread_db events.
gdb/testsuite/
2014-01-09 Pedro Alves <palves@redhat.com>
* gdb.threads/fork-thread-pending.exp: Switch to the main thread
instead of to thread 2.
* gdb.threads/signal-command-multiple-signals-pending.c (main):
Add barrier around each pthread_create call instead of around all
calls.
* gdb.threads/signal-command-multiple-signals-pending.exp (test):
Set a break on thread_function and have the child threads hit it
one at at a time.
I wrote a test that attaches to a program that constantly spawns
short-lived threads, which exposed several issues. This is one of
them.
On GNU/Linux, attaching to a multi-threaded program sometimes prints
out warnings like:
...
[New LWP 20700]
warning: unable to open /proc file '/proc/-1/status'
[New LWP 20850]
[New LWP 21019]
...
That happens because when a thread exits, and is joined, glibc does:
nptl/pthread_join.c:
pthread_join ()
{
...
if (__glibc_likely (result == 0))
{
/* We mark the thread as terminated and as joined. */
pd->tid = -1;
...
/* Free the TCB. */
__free_tcb (pd);
}
So if we attach or interrupt the program (which does an implicit "info
threads") at just the right (or rather, wrong) time, we can find and
return threads in the libthread_db/pthreads thread list with kernel
thread ID -1. I've filed glibc PR nptl/17707 for this. You'll find
more info there.
This patch handles this as a special case in GDB.
This is actually more than just a cosmetic issue. lin_lwp_attach_lwp
will think that this -1 is an LWP we're not attached to yet, and after
failing to attach will try to check we were already attached to the
process, using a waitpid call, which in this case ends up being
"waitpid (-1, ...", which obviously results in GDB potentially
discarding an event when it shouldn't...
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/gdbserver/
2015-01-09 Pedro Alves <palves@redhat.com>
* thread-db.c (find_new_threads_callback): Ignore thread if the
kernel thread ID is -1.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-nat.c (lin_lwp_attach_lwp): Assert that the lwp id we're
about to wait for is > 0.
* linux-thread-db.c (find_new_threads_callback): Ignore thread if
the kernel thread ID is -1.
... instead of relying on libthread_db.
I wrote a test that attaches to a program that constantly spawns
short-lived threads, which exposed several issues. This is one of
them.
On Linux, we need to attach to all threads of a process (thread group)
individually. We currently rely on libthread_db to list the threads,
but that is problematic, because libthread_db relies on reading data
structures out of the inferior (which may well be corrupted). If
threads are being created or exiting just while we try to attach, we
may trip on inconsistencies in the inferior's thread list. To work
around that, when we see a seemingly corrupt list, we currently retry
a few times:
static void
thread_db_find_new_threads_2 (ptid_t ptid, int until_no_new)
{
...
if (until_no_new)
{
/* Require 4 successive iterations which do not find any new threads.
The 4 is a heuristic: there is an inherent race here, and I have
seen that 2 iterations in a row are not always sufficient to
"capture" all threads. */
...
That heuristic may well fail, and when it does, we end up with threads
in the program that aren't under GDB's control. That's obviously bad
and results in quite mistifying failures, like e.g., the process dying
for seeminly no reason when a thread that wasn't attached trips on a
breakpoint.
There's really no reason to rely on libthread_db for this nowadays
when we have /proc mounted. In that case, which is the usual case, we
can list the LWPs from /proc/PID/task/. In fact, GDBserver is already
doing this. The patch factors out that code that knows to walk the
task/ directory out of GDBserver, and makes GDB use it too.
Like GDBserver, the patch makes GDB attach to LWPs and _not_ wait for
them to stop immediately. Instead, we just tag the LWP as having an
expected stop. Because we can only set the ptrace options when the
thread stops, we need a new flag in the lwp structure to keep track of
whether we've already set the ptrace options, just like in GDBserver.
Note that nothing issues any ptrace command to the threads between the
PTRACE_ATTACH and the stop, so this is safe (unlike one scenario
described in gdbserver's linux-low.c).
When we attach to a program that has threads exiting while we attach,
it's easy to race with a thread just exiting as we try to attach to
it, like:
#1 - get current list of threads
#2 - attach to each listed thread
#3 - ooops, attach failed, thread is already gone
As this is pretty normal, we shouldn't be issuing a scary warning in
step #3.
When #3 happens, PTRACE_ATTACH usually fails with ESRCH, but sometimes
we'll see EPERM as well. That happens when the kernel still has the
thread in its task list, but the thread is marked as dead.
Unfortunately, EPERM is ambiguous and we'll get it also on other
scenarios where the thread isn't dead, and in those cases, it's useful
to get a warning. To distiguish the cases, when we get an EPERM
failure, we open /proc/PID/status, and check the thread's state -- if
the /proc file no longer exists, or the state is "Z (Zombie)" or "X
(Dead)", we ignore the EPERM error silently; otherwise, we'll warn.
Unfortunately, there seems to be a kernel race here. Sometimes I get
EPERM, and then the /proc state still indicates "R (Running)"... If
we wait a bit and retry, we do end up seeing X or Z state, or get an
ESRCH. I thought of making GDB retry the attach a few times, but even
with a 500ms wait and 4 retries, I still see the warning sometimes. I
haven't been able to identify the kernel path that causes this yet,
but in any case, it looks like a kernel bug to me. As this just
results failure to suppress a warning that we've been printing since
about forever anyway, I'm just making the test cope with it, and issue
an XFAIL.
gdb/gdbserver/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_attach_fail_reason_string): Move to
nat/linux-ptrace.c, and rename.
(linux_attach_lwp): Update comment.
(attach_proc_task_lwp_callback): New function.
(linux_attach): Adjust to rename and use
linux_proc_attach_tgid_threads.
(linux_attach_fail_reason_string): Delete declaration.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-nat.c (attach_proc_task_lwp_callback): New function.
(linux_nat_attach): Use linux_proc_attach_tgid_threads.
(wait_lwp, linux_nat_filter_event): If not set yet, set the lwp's
ptrace option flags.
* linux-nat.h (struct lwp_info) <must_set_ptrace_flags>: New
field.
* nat/linux-procfs.c: Include <dirent.h>.
(linux_proc_get_int): New parameter "warn". Handle it.
(linux_proc_get_tgid): Adjust.
(linux_proc_get_tracerpid): Rename to ...
(linux_proc_get_tracerpid_nowarn): ... this.
(linux_proc_pid_get_state): New function, factored out from
(linux_proc_pid_has_state): ... this. Add new parameter "warn"
and handle it.
(linux_proc_pid_is_gone): New function.
(linux_proc_pid_is_stopped): Adjust.
(linux_proc_pid_is_zombie_maybe_warn)
(linux_proc_pid_is_zombie_nowarn): New functions.
(linux_proc_pid_is_zombie): Use
linux_proc_pid_is_zombie_maybe_warn.
(linux_proc_attach_tgid_threads): New function.
* nat/linux-procfs.h (linux_proc_get_tgid): Update comment.
(linux_proc_get_tracerpid): Rename to ...
(linux_proc_get_tracerpid_nowarn): ... this, and update comment.
(linux_proc_pid_is_gone): New declaration.
(linux_proc_pid_is_zombie): Update comment.
(linux_proc_pid_is_zombie_nowarn): New declaration.
(linux_proc_attach_lwp_func): New typedef.
(linux_proc_attach_tgid_threads): New declaration.
* nat/linux-ptrace.c (linux_ptrace_attach_fail_reason): Adjust to
use nowarn functions.
(linux_ptrace_attach_fail_reason_string): Move here from
gdbserver/linux-low.c and rename.
(ptrace_supports_feature): If the current ptrace options are not
known yet, check them now, instead of asserting.
* nat/linux-ptrace.h (linux_ptrace_attach_fail_reason_string):
Declare.
Some debug output in linux-thread-db.c was being sent to gdb_stdout,
and some to gdb_stderr, while the right place to send debug output to is
gdb_stdlog.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-thread-db.c (thread_db_find_new_threads_silently)
(try_thread_db_load_1, try_thread_db_load, thread_db_load_search)
(find_new_threads_once): Print debug output on gdb_stdlog.
We already skip "attach" tests if the target board is remote, in
dejagnu's sense, as we use TCL's exec to spawn the program on the
build machine. We should also skip these tests if testing with
"target remote" or other stub-like targets where "attach" doesn't make
sense.
Add a helper procedure that centralizes the checks a test that needs
to spawn a program for testing "attach" and make all test files that
use spawn_wait_for_attach check it.
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* lib/gdb.exp (can_spawn_for_attach): New procedure.
(spawn_wait_for_attach): Error out if can_spawn_for_attach returns
false.
* gdb.base/attach.exp: Use can_spawn_for_attach instead of
checking whether the target board is remote.
* gdb.multi/multi-attach.exp: Likewise.
* gdb.python/py-sync-interp.exp: Likewise.
* gdb.server/ext-attach.exp: Likewise.
* gdb.python/py-prompt.exp: Use can_spawn_for_attach before the
tests that need to attach, instead of checking whether the target
board is remote at the top of the file.
a 2-byte JMP instruction, when this can be done safely.
* elf32-msp430.c (msp430_elf_relax_section): Add relaxation of
16-bit absolute BR instructions to 10-bit pc-relative JMP
instructions.
PR binutils/17512
* coffcode.h (coff_slurp_symbol_table): Return false if we failed
to load the line table.
* elf.c (_bfd_elf_map_sections_to_segments): Enforce a minimum
maxpagesize of 1.
* peXXigen.c (_bfd_XX_bfd_copy_private_bfd_data_common): Fail if
the Data Directory Size is too large.
* objcopy.c (copy_object): Free the symbol table if no symbols
could be loaded.
(copy_file): Use bfd_close_all_done to close files that could not
be copied.
PR binutils/17512
* sysdump.c (getINT): Fail if reading off the end of the buffer.
Replace call to abort with a call to fatal.
(getCHARS): Prevetn reading off the end of the buffer.
The original test output expectations cause it to fail when configure
determines enable_initfini_array=no (which was observed on a cross
build on an old 32-bit host, pointing out that taking into account host
properties in such a case is bogus anyway).
ld/testsuite/
2015-01-08 Jan Beulich <jbeulich@suse.com>
* ld-x86-64/pr14207.d: Adjust expecations to cover the
enable_initfini_array=no case.
I see the error message "access outside bounds of object referenced
via synthetic pointer" in the two fails below of mips gdb testing
print d[-2]^M
access outside bounds of object referenced via synthetic pointer^M
(gdb) FAIL: gdb.dwarf2/implptrconst.exp: print d[-2]
(gdb) print/d p[-1]^M
access outside bounds of object referenced via synthetic pointer^M
(gdb) FAIL: gdb.dwarf2/implptrpiece.exp: print/d p[-1]
in the first test, 'd[-2]' is processed by GDB as '* (&d[-2])'. 'd'
is a synthetic pointer, so its value is zero, the address of 'd[-2]'
is -2. In dwarf2loc.c:indirect_pieced_value,
/* This is an offset requested by GDB, such as value subscripts.
However, due to how synthetic pointers are implemented, this is
always presented to us as a pointer type. This means we have to
sign-extend it manually as appropriate. */
byte_offset = value_as_address (value);
if (TYPE_LENGTH (value_type (value)) < sizeof (LONGEST))
byte_offset = gdb_sign_extend (byte_offset,
8 * TYPE_LENGTH (value_type (value)));
byte_offset += piece->v.ptr.offset;
We know that the value is really an offset instead of address, so the
fix is to extract the value as an (signed) offset.
gdb:
2015-01-08 Pedro Alves <palves@redhat.com>
Yao Qi <yao@codesourcery.com>
* dwarf2loc.c (indirect_pieced_value): Don't call
gdb_sign_extend. Call extract_signed_integer instead.
* utils.c (gdb_sign_extend): Remove.
* utils.h (gdb_sign_extend): Remove declaration.
fuzzed binaries.
PR binutils/17512
* nlmconv.c (i386_mangle_relocs): Skip relocs without an
associated symbol.
(powerpc_mangle_relocs): Skip unrecognised relocs. Check address
range before applying a reloc.
The special handling of C++ special symbol
generates symbols that have no language.
Those symbols cannot be displayed correctly in the backtrace stack.
See
https://sourceware.org/bugzilla/show_bug.cgi?id=17811
for details and examples in C++ and pascal language.
The patch below fixes this issue, by
setting language of new symbol before
special handling of special C++ symbols.
2015-01-07 Pierre Muller <muller@sourceware.org>
PR symtab/17811
* stabsread.c (define_symbol): Set language for C++ special symbols.
The test entry-values.exp doesn't recognize the call instructions
on MIPS, such as JAL, JALS and etc, so this patch sets call_insn
to match various jump and branch instructions first.
Currently, we assume the next instruction address of call instruction
is the address returned from foo, however it is not correct on MIPS
which has delay slot. We extend variable call_insn to match one
instruction after jump or branch instruction, so that
$returned_from_foo is correct on MIPS.
All tests in entry-values.exp are PASS.
gdb/testsuite:
2015-01-08 Yao Qi <yao@codesourcery.com>
* gdb.trace/entry-values.exp: Set call_insn for MIPS target.
PR binutils/17512
* objdump.c (display_any_bfd): Add a depth limit to nested archive
display in order to avoid infinite loops.
* srconv.c: Replace calls to abort with calls to fatal with an
error message.
Currently when we start an inferior we have the inferior inherit our
terminal state. Under TUI, our terminal is highly modified by ncurses
and readline. So when starting an inferior under TUI, the inferior will
have a highly modified terminal state which will interfere with standard
I/O. For example,
$ gdb gdb
(gdb) break main
(gdb) run
(gdb) print puts ("a\nb")
a
b
$1 = 4
(gdb) [enter TUI mode]
(gdb) run
(gdb) [exit TUI mode]
(gdb) print puts ("a\nb")
a
b
$2 = 4
(gdb) print puts ("a\r\nb\r")
a
b
$3 = 6
As you can see, when we start the inferior under the regular interface,
puts() prints the text properly. But when we start the inferior under
TUI, puts() does not print the text properly. This is because when we
start the inferior under TUI it inherits our current terminal state
which has been modified by ncurses to, among other things, require an
explicit \r\n to print a new line. As a result the inferior performs
standard I/O in an unexpected way.
Because of this discrepancy, it doesn't seem like a good idea to have
the inferior inherit our _current_ terminal state for it may have been
modified by readline and/or ncurses. Instead, we should have the
inferior inherit a pristine snapshot of our terminal state taken before
readline or ncurses have had a chance to alter it. This enables the
inferior to run in a more accurate way, more closely mimicking the
program's behavior had it run standalone. And it fixes the above
mentioned issue.
Tested on x86_64-unknown-linux-gnu.
gdb/ChangeLog:
* terminal.h (set_initial_gdb_ttystate): Declare.
* inflow.c (initial_gdb_ttystate): New static variable.
(set_initial_gdb_ttystate): New setter.
(child_terminal_init_with_pgrp): Copy initial_gdb_ttystate
instead of our current terminal state.
* top.c (gdb_init): Call set_initial_gdb_ttystate.
Mention that readelf can be used as a test program in the comment of
run_dump_test.
ld/testsuite/ChangeLog:
* lib/ld-lib.exp (run_dump_test): Extend comment to mention
readelf.
... using automake 1.11.1, which is the version we're currently
using throughout, instead of 1.11.3. This should be a no-op in
practice, but will help automake/aclocal version-related
differences to cloud real changes being made.
sim/common/ChangeLog:
* aclocal.m4, configure: Regenerate using automake 1.11.1.
Using e.g.
.arch_extension simd
.arch_extension nocrypto
so far results in SIMD support getting disabled, which I can't see being
the purpose of the "no"-prefixed variants of architecture extension
specifications.
Of course it is questionable whether the current, counter intuitive
behavior needs to be retained, and the new behavior perhaps be made work
through e.g. a newly recognized "no-" prefix.
gas/
2015-01-07 Jan Beulich <jbeulich@suse.com>
* gas/config/tc-arm.c (struct arm_option_extension_value_table):
Split field "value" into fields "merge_value" and "clear_value".
(arm_extensions): Adjust initializer accordingly.
PR binutils/17512
* reloc.c (bfd_get_reloc_size): Handle a reloc size of -1.
(bfd_perform_relocation): Include the size of the reloc in the
test for an out of range relocation.
(bfd_generic_get_relocated_section_contents): Remove reloc range
test.
PR binutils/17512
* coffdump.c (dump_coff_section): Check for a symbol being
available before printing its name.
(main): Check the return value from coff_grok.
* coffgrok.c: Reformat and tidy.
Add range checks to most functions.
(coff_grok): Return NULL if the input bfd is not in a COFF
format.
* coffgrok.h: Reformat and tidy.
(struct coff_section): Change the nrelocs field to unsigned.
* srconv.c (main): Check the return value from coff_grok.
* coff-i860.c (CALC_ADDEND): Always set an addend value.
* tekhex.c (getvalue): Add an end pointer parameter. Use it to
avoid reading off the end of the buffer.
(getsym): Likewise.
(first_phase): Likewise.
(pass_over): Pass an end pointer to the invoked function.
This fixes a similar error as in the Python support code where
trying to create an empty array.
In guile/scm-type.c::tyscm_array_1, the funtion raises an exception
if N2 < N1:
if (n2 < n1)
{
gdbscm_out_of_range_error (func_name, SCM_ARG3,
But it should be doing so if N2 == N1 - 1, since that would simply
be an empty array, not an array with a negative length.
gdb/ChangeLog:
* guile/scm-type.c (tyscm_array_1): Do not raise out-of-range
error if N2 is equal to N1 - 1.
The following python command fails:
(gdb) python print gdb.lookup_type('char').array(1, 0)
Traceback (most recent call last):
File "<string>", line 1, in <module>
ValueError: Array length must not be negative
Error while executing Python code.
The above is trying to create an empty array, which is fairly command
in Ada.
gdb/ChangeLog:
* python/py-type.c (typy_array_1): Do not raise negative-length
exception if N2 is equal to N1 - 1.
gdb/testsuite/ChangeLog:
* gdb.python/py-type.exp: Add a couple test about empty
array creation, and negative-length array creation.
PR binutils/17512
* nm.c (print_symbol): Add 'is_synthetic' parameter. Use it to
help initialize the info.elfinfo field.
(print_size_symbols): Add 'synth_count' parameter. Use it to set
the is_synthetic parameter when calling print_symbol.
(print_symbols): Likewise.
(display_rel_file): Pass synth_count to printing function.
(display_archive): Break loop if the last archive displayed
matches the current archive.
* size.c (display_archive): Likewise.
* archive.c (do_slurp_bsd_armap): Make sure that the parsed sized
is at least big enough for the header to be read.
* elf32-i386.c (elf_i386_get_plt_sym_val): Skip unknown relocs.
* mach-o.c (bfd_mach_o_get_synthetic_symtab): Add range checks.
(bfd_mach_o_read_command): Prevetn duplicate error messages about
unrecognized commands.
* syms.c (_bfd_stab_section_find_nearest_line): Add range checks
when indexing into the string table.
PR binutils/17531
* dwarf.c (alloc_num_debug_info_entries): New variable.
(process_debug_info): Set it. Use it to avoid displaying
attributes for which there is no info.
(display_debug_abbrev): Check that the debug_info_entry index is
valid before using it.
(display_loc_list_dwo): Likewise.
(process_cu_tu_index): Add range check for an overlarge dw_sect
value.
(free_debug_memory): Reset alloc_num_debug_info_entries.
* readelf.c (slurp_ia64_unwind_table): Warn if the reloc could not
be indentified.
(dynamic_section_mips_val): Warn if the timestamp is invalid.
(print_mips_got_entry): Add a data_end parameter. Warn if a read
would go beyond the end of the data, and return an error value.
(process_mips_specific): Do not read options from beyond the end
of the section.
Correct code to display optional data at the end of an option.
Warn if there are too many GOT symbols.
Update calls to print_mips_got_entry, and handle error returns.
