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Re: [PATCH] Remove support for thread events without PTRACE_EVENT_CLONE in GDB.
- From: Antoine Tremblay <antoine dot tremblay at ericsson dot com>
- To: Pedro Alves <palves at redhat dot com>, <gdb-patches at sourceware dot org>
- Date: Thu, 10 Dec 2015 10:21:12 -0500
- Subject: Re: [PATCH] Remove support for thread events without PTRACE_EVENT_CLONE in GDB.
- Authentication-results: sourceware.org; auth=none
- References: <1449682744-11243-1-git-send-email-antoine dot tremblay at ericsson dot com> <56699099 dot 2080908 at redhat dot com>
On 12/10/2015 09:47 AM, Pedro Alves wrote:
On 12/09/2015 05:39 PM, Antoine Tremblay wrote:
Before, on systems that did not support PTRACE_EVENT_CLONE, both GDB and
GDBServer coordinated with libthread_db.so to insert breakpoints at magic
locations in libpthread.so, in order to break at thread creation and
Support for thread events was removed from GDBServer as patch:
This patch removes support for thread events in GDB.
No regressions found on Ubuntu 14.04 x86_64.
* breakpoint.c (create_thread_event_breakpoint): Remove.
That's still used:
$ grep create_thread_event_breakpoint gdb/*
gdb/aix-thread.c: if (!create_thread_event_breakpoint (target_gdbarch (), pd_brk_addr))
Ouch, I had missed that one. I'll re-add the function.
Also I noticed I forgot to remove the declaration in breakpoint.h I'll
fix that for remove_thread_event_breakpoint.
- /* Under GNU/Linux, we have to attach to each and every thread. */
- if (target_has_execution
- && tp == NULL)
- int res;
- res = lin_lwp_attach_lwp (ptid_build (ptid_get_pid (ptid),
- ti_p->ti_lid, 0));
- if (res < 0)
- /* Error, stop iterating. */
Is lin_lwp_attach_lwp used anywhere after this?
No indeed, Removing.
@@ -1592,24 +1200,10 @@ find_new_threads_callback (const td_thrhandle_t *th_p, void *data)
if (ti.ti_tid == 0)
- /* A thread ID of zero means that this is the main thread, but
- glibc has not yet initialized thread-local storage and the
- pthread library. We do not know what the thread's TID will
- be yet. Just enable event reporting and otherwise ignore
- it. */
You shouldn't remove the whole comment -- it's still all correct
except the last sentence.
Yes I hesitated on that one, it felt like the reason for the comment was
the last sentence so I removed it.
But I'm OK with leaving it there.
V2 follows in next mail.