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If you do "interrupt -a" just while some thread is stepping over a breakpoint, gdb trips on an internal error. The test added by this patch manages to trigger this consistently by spawning a few threads that are constantly tripping on a conditional breakpoint whose condition always evaluates to false. With current gdb, you get: ~~~ interrupt -a .../src/gdb/inline-frame.c:343: internal-error: void skip_inline_frames(ptid_t): Assertion `find_inline_frame_state (ptid) == NULL' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) FAIL: gdb.threads/interrupt-while-step-over.exp: displaced-stepping=on: iter=0: interrupt -a (GDB internal error) [...] .../src/gdb/inline-frame.c:343: internal-error: void skip_inline_frames(ptid_t): Assertion `find_inline_frame_state (ptid) == NULL' failed. A problem internal to GDB has been detected, further debugging may prove unreliable. Quit this debugging session? (y or n) FAIL: gdb.threads/interrupt-while-step-over.exp: displaced-stepping=off: iter=0: wait for stops (GDB internal error) ~~~ The assertion triggers because we're processing a stop for a thread that had already stopped before and thus had already its inline-frame state filled in. Calling handle_inferior_event_1 directly within a "thread_stop_requested" observer is something that I've wanted to get rid of before, for being fragile. Nowadays, infrun is aware of threads with pending events, so we can use that instead, and let the normal fetch_inferior_event -> handle_inferior_event code path handle the forced stop. The change to finish_step_over is necessary because sometimes a thread that was told to PTRACE_SINGLESTEP reports back a SIGSTOP instead of a SIGTRAP (i.e., we tell it to single-step, and then interrupt it quick enough that on the kernel side the thread dequeues the SIGTOP before ever having had a chance of executing the instruction to be stepped). SIGSTOP gets translated to a GDB_SIGNAL_0. And then finish_step_over would miss calling clear_step_over_info, and thus miss restarting the other threads (which in this case of threads with pending events, means setting their "resumed" flag, so their pending events can be consumed). And now that we always restart threads in finish_step_over, we no longer need to do that in handle_signal_stop. Tested on x86_64 Fedora 23, native and gdbserver. gdb/ChangeLog: 2017-03-08 Pedro Alves <palves@redhat.com> PR gdb/18360 * infrun.c (start_step_over, do_target_resume, resume) (restart_threads): Assert we're not resuming a thread that is meant to be stopped. (infrun_thread_stop_requested_callback): Delete. (infrun_thread_stop_requested): If the thread is internally stopped, queue a pending stop event and clear the thread's inline-frame state. (handle_stop_requested): New function. (handle_syscall_event, handle_inferior_event_1): Use handle_stop_requested. (handle_stop_requested): New function. (handle_signal_stop): Set the thread's stop_signal here instead of at caller. (finish_step_over): Clear step over info unconditionally. (handle_signal_stop): If the user had interrupted the event thread, consider the stop a random signal. (handle_signal_stop) <signal arrived while stepping over breakpoint>: Don't restart threads here. (stop_waiting): Don't clear step-over info here. gdb/testsuite/ChangeLog: 2017-03-08 Pedro Alves <palves@redhat.com> PR gdb/18360 * gdb.threads/interrupt-while-step-over.c: New file. * gdb.threads/interrupt-while-step-over.exp: New file. |
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| binutils | ||
| config | ||
| cpu | ||
| elfcpp | ||
| etc | ||
| gas | ||
| gdb | ||
| gold | ||
| gprof | ||
| include | ||
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| ld | ||
| libdecnumber | ||
| libiberty | ||
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README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.