The C standard doesn't guarantee a function pointer can be cast to
void* and vice versa.
binutils/
* prdbg.c (print_debugging_info): Don't use void* for function
pointer param.
* budbg.h (print_debugging_info): Update prototype.
gas/
* read.c (s_altmacro, s_reloc): Make definition static.
gdb/testsuite/ChangeLog:
* lib/dwarf.exp (Dwarf): Flag an error if a numeric attribute value
is given without an explicit form.
* gdb.dwarf2/arr-subrange.exp: Specify forms for all numeric
attributes.
* gdb.dwarf/corrupt.exp: Ditto.
* gdb.dwarf2/enum-type.exp: Ditto.
* gdb.trace/entry-values.exp: Ditto.
* gdb.trace/unavailable-dwarf-piece.exp: Ditto.
clear_symtab_users calls breakpoint_re_set before
observer_notify_new_objfile(NULL), and thus symbol lookup
done during breakpoint_re_set will see a stale cache.
Presumably we just need to move the call to observer_notify_new_objfile(NULL)
to before breakpoint_re_set, but need to check for other such issues,
and 7.9 is scheduled to branch tomorrow.
Reverts commits:
b2fb95e006400678a494d98b9ccbcc77087adf50
gdb/ChangeLog:
* symtab.c (eq_symbol_entry): Use SYMBOL_SEARCH_NAME and
symbol_matches_domain for symbol comparisons.
* symtab.c (symbol_cache_mark_found): Improve function comment.
Rename parameter objfile to objfile_context.
(symbol_cache_mark_not_found): Improve function comment.
Add symbol lookup cache.
* NEWS: Document new options and commands.
* symtab.c (symbol_cache_key): New static global.
(DEFAULT_SYMBOL_CACHE_SIZE, MAX_SYMBOL_CACHE_SIZE): New macros.
(SYMBOL_LOOKUP_FAILED): New macro.
(symbol_cache_slot_state): New enum.
(block_symbol_cache): New struct.
(symbol_cache): New struct.
(new_symbol_cache_size, symbol_cache_size): New static globals.
(hash_symbol_entry, eq_symbol_entry): New functions.
(symbol_cache_byte_size, resize_symbol_cache): New functions.
(make_symbol_cache, free_symbol_cache): New functions.
(get_symbol_cache, symbol_cache_cleanup): New function.
(set_symbol_cache_size, set_symbol_cache_size_handler): New functions.
(symbol_cache_lookup, symbol_cache_clear_slot): New function.
(symbol_cache_mark_found, symbol_cache_mark_not_found): New functions.
(symbol_cache_flush, symbol_cache_dump): New functions.
(maintenance_print_symbol_cache): New function.
(maintenance_flush_symbol_cache): New function.
(symbol_cache_stats): New function.
(maintenance_print_symbol_cache_statistics): New function.
(symtab_new_objfile_observer): New function.
(symtab_free_objfile_observer): New function.
(lookup_static_symbol, lookup_global_symbol): Use symbol cache.
(_initialize_symtab): Init symbol_cache_key. New parameter
maint symbol-cache-size. New maint commands print symbol-cache,
print symbol-cache-statistics, flush-symbol-cache.
Install new_objfile, free_objfile observers.
gdb/doc/ChangeLog:
* gdb.texinfo (Symbols): Document new commands
"maint print symbol-cache", "maint print symbol-cache-statistics",
"maint flush-symbol-cache". Document new option
"maint set symbol-cache-size".
gdb/ChangeLog:
PR gdb/15830
* NEWS: The "maint demangle" command is renamed as "demangle".
* demangle.c: #include cli/cli-utils.h, language.h.
(demangle_command): New function.
(_initialize_demangle): Add new command "demangle".
* maint.c (maintenance_demangle): Stub out.
(_initialize_maint_cmds): Update help text for "maint demangle",
and mark as deprecated.
gdb/doc/ChangeLog:
* gdb.texinfo (Debugging C Plus Plus): Mention "demangle".
(Symbols): Ditto.
(Maintenance Commands): Delete docs for "maint demangle".
gdb/testsuite/ChangeLog:
* gdb.base/maint.exp: Remove references to "maint demangle".
* gdb.cp/demangle.exp: Update. "maint demangle" -> "demangle".
Add tests for explicitly specifying language to demangle.
* gdb.dlang/demangle.exp: Ditto.
When building PIE, we should only discard space for pc-relative relocs
symbols which turn out to need copy relocs.
bfd/
PR ld/17827
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): For PIE,
only discard space for pc-relative relocs symbols which turn
out to need copy relocs.
ld/testsuite/
PR ld/17827
* ld-x86-64/pr17689.out: Updated.
* ld-x86-64/pr17689b.S: Likewise.
* ld-x86-64/pr17827.rd: New file.
* ld-x86-64/x86-64.exp: Run PR ld/17827 test.
gdb/ChangeLog:
Add symbol lookup cache.
* NEWS: Document new options and commands.
* symtab.c (symbol_cache_key): New static global.
(DEFAULT_SYMBOL_CACHE_SIZE, MAX_SYMBOL_CACHE_SIZE): New macros.
(SYMBOL_LOOKUP_FAILED): New macro.
(symbol_cache_slot_state): New enum.
(block_symbol_cache): New struct.
(symbol_cache): New struct.
(new_symbol_cache_size, symbol_cache_size): New static globals.
(hash_symbol_entry, eq_symbol_entry): New functions.
(symbol_cache_byte_size, resize_symbol_cache): New functions.
(make_symbol_cache, free_symbol_cache): New functions.
(get_symbol_cache, symbol_cache_cleanup): New function.
(set_symbol_cache_size, set_symbol_cache_size_handler): New functions.
(symbol_cache_lookup, symbol_cache_clear_slot): New function.
(symbol_cache_mark_found, symbol_cache_mark_not_found): New functions.
(symbol_cache_flush, symbol_cache_dump): New functions.
(maintenance_print_symbol_cache): New function.
(maintenance_flush_symbol_cache): New function.
(symbol_cache_stats): New function.
(maintenance_print_symbol_cache_statistics): New function.
(symtab_new_objfile_observer): New function.
(symtab_free_objfile_observer): New function.
(lookup_static_symbol, lookup_global_symbol): Use symbol cache.
(_initialize_symtab): Init symbol_cache_key. New parameter
maint symbol-cache-size. New maint commands print symbol-cache,
print symbol-cache-statistics, flush-symbol-cache.
Install new_objfile, free_objfile observers.
doc/ChangeLog:
* gdb.texinfo (Symbols): Document new commands
"maint print symbol-cache", "maint print symbol-cache-statistics",
"maint flush-symbol-cache". Document new option
"maint set symbol-cache-size".
gdb/gdbserver/ChangeLog:
* i387-fp.c (i387_cache_to_xsave): In look over
num_avx512_zmmh_high_registers, replace use of struct i387_xsave
zmmh_low_space field by use of zmmh_high_space.
Tested on x86_64-linux, using boards/native-gdbserver.exp.
When fixups are converted to a difference type within md_apply_fix, we
previously left the contents of VALP (the value that was initially
computed within write.c:fixup_segment) unchanged. This is harmless,
except that this value is used within write.c:fixup_segment once we
return from md_apply_fix to perform an overflow check.
In some cases, the value computed in write.c:fixup_segment is so wrong
that an overflow error can be triggered. These errors are incorrect.
This patch avoids the overflow errors by adjusting the value in
write.c:fixup_segment using the VALP pointer in md_apply_fix.
A test for this issue is included.
gas/ChangeLog:
* config/tc-avr.c (md_apply_fix): Update the contents of VALP for
diff fixups.
gas/testsuite/ChangeLog:
* gas/avr/large-debug-line-table.d: New file.
* gas/avr/large-debug-line-table.s: New file.
This fixes an issue where a page-aligned data section, combined with -z relro,
could lead to a gap between text and data segments larger than a page, and
we would fail to overlap the segments in the file.
gold/
* layout.cc (Layout::set_segment_offsets): Don't align start of segment
unless alignment is larger than page size.
The #line directives within GDB's autogenerated yacc files (e.g.
c-exp.c) are being incorrectly munged, causing these directives to refer
to nonexistent source files, e.g.
#line 36 "/home/patrick/binutils-gdb/gdb//home/patrick/binutils-gdb/gdb/c-exp.y"
as opposed to
#line 36 "/home/patrick/binutils-gdb/gdb/c-exp.y"
The munging happens due to a sed expression added by commit 954d8cae
whose intended purpose[1] was to work around the fact that ylwrap emitted #line
directives without any directory information, e.g.
#line 36 "c-exp.y"
So the sed expression was meant to munge such directives to refer to
absolute paths instead. But the behavior of ylwrap was changed some
years ago[2] to emit absolute paths within #line directives. And when
our local copy of ylwrap was synced by commit e30465112, the sed
expression in question became unnecessary, and indeed harmful.
This patch removes the now-obsolete sed expression. The emitted #line
directives are now correct without it.
gdb/ChangeLog:
* Makefile.in (.y.c): Don't munge yacc's #line
directives.
[1]: https://sourceware.org/ml/gdb-patches/2010-11/msg00265.html
[2]: http://git.savannah.gnu.org/cgit/automake.git/commit/lib/ylwrap?id=b6359a5f3
the X-Gene scheduling description up in the respective GCC backend.
* config/tc-arm.c (arm_cpus): Add support for APM X-Gene 1 and
X-Gene 2.
* doc/c-arm.texi (ARM Options): Mention xgene1 and xgene2.
This patch primarily rewrites defaulted_query() to use
gdb_readline_wrapper() to prompt the user for input, like
prompt_for_continue() does. The motivation for this rewrite is to be
able to reuse the default query hook in TUI, obviating the need for a
custom TUI query hook.
However, having TUI use the default query mechanism exposed a couple of
latent bugs in tui_redisplay_readline() related to the handling of
multi-line prompts, in particular GDB's multi-line quit prompt.
The first issue is an off-by-one error in the calculation of the height
of the prompt. The check in question should be col <= prev_col, not c <
prev_col, to properly account for the case when a prompt contains
multiple consecutive newlines. Failing to do so makes TUI have the
wrong idea of the vertical height of the prompt. This patch fixes the
column check.
The second issue is that cur_line does not get updated to reflect the
cursor position if the user's prompt cursor is at the end of the prompt
(i.e. if rl_point == rl_end). cur_line only gets updated if rl_point
lies between 0..rl_end-1 because that is the bounds of the for loop
responsible for updating cur_line. This patch changes the loop's bounds
to 0..rl_end so that cur_line always gets updated.
With these two bug fixes out of the way, the default query mechanism
works well in TUI even with multi-line prompts like GDB's quit prompt.
gdb/ChangeLog:
* utils.c (defaulted_query): Rewrite to use gdb_readline_wrapper
to prompt for input.
* tui/tui-hooks.c (tui_query_hook): Remove.
(tui_install_hooks): Don't set deprecated_query_hook.
* tui/tui-io.c (tui_redisplay_readline): Fix off-by-one error in
height calculation. Always update the command window's cur_line.
This commit adds a non-stop mode test originally inspired by
signal-while-stepping-over-bp-other-thread.exp, that exposes the
thread starvation issues fixed by the previous patches. It sets a set
of threads stepping in parallel, and has one of them get a signal.
Without the previous fixes, this would fail with timeouts.
gdb/testsuite/
2015-01-09 Pedro Alves <palves@redhat.com>
* gdb.threads/non-stop-fair-events.c: New file.
* gdb.threads/non-stop-fair-events.exp: New file.
This patch applies the same starvation avoidance improvements of the
previous patch to the Linux gdbserver side.
Without this, the test added by the following commit
(gdb.threads/non-stop-fair-events.exp) always fails with time outs.
gdb/gdbserver/
2015-01-09 Pedro Alves <palves@redhat.com>
* linux-low.c (step_over_bkpt): Move higher up in the file.
(handle_extended_wait): Don't store the stop_pc here.
(get_stop_pc): Adjust comments and rename to ...
(check_stopped_by_breakpoint): ... this. Record whether the LWP
stopped for a software breakpoint or hardware breakpoint.
(thread_still_has_status_pending_p): New function.
(status_pending_p_callback): Use
thread_still_has_status_pending_p. If the event is no longer
interesting, resume the LWP.
(handle_tracepoints): Add assert.
(maybe_move_out_of_jump_pad): Remove cancel_breakpoints call.
(wstatus_maybe_breakpoint): New function.
(cancel_breakpoint): Delete function.
(check_stopped_by_watchpoint): New function, factored out from
linux_low_filter_event.
(lp_status_maybe_breakpoint): Delete function.
(linux_low_filter_event): Remove filter_ptid argument.
Leave thread group exits pending here. Store the LWP's stop PC.
Always leave events pending.
(linux_wait_for_event_filtered): Pull all events out of the
kernel, and leave them all pending.
(count_events_callback, select_event_lwp_callback): Consider all
events.
(cancel_breakpoints_callback, linux_cancel_breakpoints): Delete.
(select_event_lwp): Only give preference to the stepping LWP in
all-stop mode. Adjust comments.
(ignore_event): New function.
(linux_wait_1): Delete 'retry' label. Use ignore_event. Remove
references to cancel_breakpoints. Adjust to renames. Also give
equal priority to all LWPs that have had events in non-stop mode.
If reporting a software breakpoint event, unadjust the LWP's PC.
(linux_wait): If linux_wait_1 returned an ignored event, retry.
(stuck_in_jump_pad_callback, move_out_of_jump_pad_callback):
Adjust.
(linux_resume_one_lwp): Store the LWP's PC. Adjust.
(resume_status_pending_p): Use thread_still_has_status_pending_p.
(linux_stopped_by_watchpoint): Adjust.
(linux_target_ops): Remove reference to linux_cancel_breakpoints.
* linux-low.h (enum lwp_stop_reason): New.
(struct lwp_info) <stop_pc>: Adjust comment.
<stopped_by_watchpoint>: Delete field.
<stop_reason>: New field.
* linux-x86-low.c (x86_linux_prepare_to_resume): Adjust.
* mem-break.c (software_breakpoint_inserted_here)
(hardware_breakpoint_inserted_here): New function.
* mem-break.h (software_breakpoint_inserted_here)
(hardware_breakpoint_inserted_here): Declare.
* target.h (struct target_ops) <cancel_breakpoints>: Remove field.
(cancel_breakpoints): Delete.
* tracepoint.c (clear_installed_tracepoints, stop_tracing)
(upload_fast_traceframes): Remove references to
cancel_breakpoints.
Running the testsuite with a series that reimplements user-visible
all-stop behavior on top of a target running in non-stop mode revealed
problems related to event starvation avoidance.
For example, I see
gdb.threads/signal-while-stepping-over-bp-other-thread.exp failing.
What happens is that GDB core never gets to see the signal event. It
ends up processing the events for the same threads over an over,
because Linux's waitpid(-1, ...) returns that first task in the task
list that has an event, starving threads on the tail of the task list.
So I wrote a non-stop mode test originally inspired by
signal-while-stepping-over-bp-other-thread.exp, to stress this
independently of all-stop on top of non-stop. Fixing it required the
changes described below. The test will be added in a following
commit.
1) linux-nat.c has code in place that picks an event LWP at random out
of all that have had events. This is because on the kernel side,
"waitpid(-1, ...)" just walks the task list linearly looking for the
first that had an event. But, this code is currently only used in
all-stop mode. So with a multi-threaded program that has multiple
events triggering debug events in parallel, GDB ends up starving some
threads.
To make the event randomization work in non-stop mode too, the patch
makes us pull out all the already pending events on the kernel side,
with waitpid, before deciding which LWP to report to the core.
There's some code in linux_wait that takes care of leaving events
pending if they were for LWPs the caller is not interested in. The
patch moves that to linux_nat_filter_event, so that we only have one
place that leaves events pending. With that in place, conceptually,
the flow is simpler and more normalized:
#1 - walk the LWP list looking for an LWP with a pending event to report.
#2 - if no pending event, pull events out of the kernel, and store
them in the LWP structures as pending.
#3- goto #1.
2) Then, currently the event randomization code only considers SIGTRAP
(or trap-like) events. That means that if e.g., have have multiple
threads stepping in parallel that hit a breakpoint that needs stepping
over, and one gets a signal, the signal may end up never getting
processed, because GDB will always be giving priority to the SIGTRAPs.
The patch fixes this by making the randomization code consider all
kinds of pending events.
3) If multiple threads hit a breakpoint, we report one of those, and
"cancel" the others. Cancelling means decrementing the PC, and
discarding the event. If the next time the LWP is resumed the
breakpoint is still installed, the LWP should hit it again, and we'll
report the hit then. The problem I found is that this delays threads
from advancing too much, with the kernel potentially ending up
scheduling the same threads over and over, and others not advancing.
So the patch switches away from cancelling the breakpoints, and
instead remembering that the LWP had stopped for a breakpoint. If on
resume the breakpoint is still installed, we report it. If it's no
longer installed, we discard the pending event then. This is actually
how GDBserver used to handle this before d50171e4 (Teach linux
gdbserver to step-over-breakpoints), but with the difference that back
then we'd delay adjusting the PC until resuming, which made it so that
"info threads" could wrongly see threads with unadjusted PCs.
gdb/
2015-01-09 Pedro Alves <palves@redhat.com>
* breakpoint.c (hardware_breakpoint_inserted_here_p): New
function.
* breakpoint.h (hardware_breakpoint_inserted_here_p): New
declaration.
* linux-nat.c (linux_nat_status_is_event): Move higher up in file.
(linux_resume_one_lwp): Store the thread's PC. Adjust to clear
stop_reason.
(check_stopped_by_watchpoint): New function.
(save_sigtrap): Reimplement.
(linux_nat_stopped_by_watchpoint): Adjust.
(linux_nat_lp_status_is_event): Delete.
(stop_wait_callback): Only call save_sigtrap after storing the
pending status.
(status_callback): If the thread had been stopped for a breakpoint
that has since been removed, discard the event and resume the LWP.
(count_events_callback, select_event_lwp_callback): Use
lwp_status_pending_p instead of linux_nat_lp_status_is_event.
(cancel_breakpoint): Rename to ...
(check_stopped_by_breakpoint): ... this. Record whether the LWP
stopped for a software breakpoint or hardware breakpoint.
(select_event_lwp): Only give preference to the stepping LWP in
all-stop mode. Adjust comments.
(stop_and_resume_callback): Remove references to new_pending_p.
(linux_nat_filter_event): Likewise. Leave exit events of the
leader thread pending here. Handle signal short circuiting here.
Only call save_sigtrap after storing the pending waitstatus.
(linux_nat_wait_1): Remove 'retry' label. Remove references to
new_pending. Don't handle leaving events the caller is not
interested in pending here, nor handle signal short-circuiting
here. Also give equal priority to all LWPs that have had events
in non-stop mode. If reporting a software breakpoint event,
unadjust the LWP's PC.
* linux-nat.h (enum lwp_stop_reason): New.
(struct lwp_info) <stop_pc>: New field.
(struct lwp_info) <stopped_by_watchpoint>: Delete field.
(struct lwp_info) <stop_reason>: New field.
* x86-linux-nat.c (x86_linux_prepare_to_resume): Adjust.
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.
