Respected community members, This is the patch version 3 of the fix. This patch clears the gdb.thread/thread_events.exp test case. === gdb Summary === # of expected passes 11 /current_gdb/binutils-gdb/gdb/gdb version 15.0.50.20240325-git -nw -nx -q -iex "set height 0" -iex "set width 0" -data-directory /current_gdb/binutils-gdb/gdb/data-directory And clears program 1 attached below this email as well. See the GDB output for the same as well in AIX. We have only one small problem. Consider the gdb.threads/thread_events.exp test case. See program 2 below this email (same as the .c file in the test case). Here is the output of GDB in AIX. Reading symbols from testsuite/gdb.threads/thread_events... (gdb) b main Breakpoint 1 at 0x100007dc: file gdb.threads/thread_events.c, line 41. (gdb) r Starting program: /current_gdb/binutils-gdb/gdb/testsuite/gdb.threads/thread_events Breakpoint 1, main (argc=1, argv=0x2ff22940) at gdb.threads/thread_events.c:41 41 if (pthread_create (&thread, NULL, threadfunc, NULL) != 0) (gdb) b after_join_func Breakpoint 2 at 0x10000778: file gdb.threads/thread_events.c, line 34. (gdb) b threadfunc Breakpoint 3 at 0x10000718: file gdb.threads/thread_events.c, line 27. (gdb) c Continuing. [New Thread 258 (tid 25231759)] [Switching to Thread 258 (tid 25231759)] Thread 2 hit Breakpoint 3, threadfunc (arg=0x0) at gdb.threads/thread_events.c:27 27 printf ("in threadfunc\n"); (gdb) Continuing. in threadfunc [Thread 258 (tid 25231759) exited] [Switching to Thread 1 (tid 28115323)] Thread 1 hit Breakpoint 2, after_join_func () at gdb.threads/thread_events.c:34 34 printf ("finished\n"); (gdb) info threads ./../gdbsupport/intrusive_list.h:468: internal-error: erase_element: Assertion `elem_node->prev != nullptr' failed. A problem internal to GDB has been detected, When I do info threads here this fails. Did this happen because we delete the thread?? I am not sure why this happened?? Kindly let me know what we missed or where I went wrong in the patch. Awaiting a reply. Have a nice day ahead. Thanks and regards, Aditya. Program 1 #include #include #include #include #include pthread_barrier_t barrier; #define NUM_THREADS 3 void * thread_function (void *arg) { /* This ensures that the breakpoint is only hit after both threads are created, so the test can always switch to the non-event thread when the breakpoint triggers. */ // pthread_barrier_wait (&barrier); printf ("Hello World \n"); /* break here */ } int main (void) { int i; alarm (300); pthread_barrier_init (&barrier, NULL, NUM_THREADS); for (i = 0; i < NUM_THREADS; i++) { pthread_t thread; int res; res = pthread_create (&thread, NULL, thread_function, NULL); assert (res == 0); } printf ("More threads \n"); for (i = 0; i < NUM_THREADS; i++) { pthread_t thread; int res; res = pthread_create (&thread, NULL, thread_function, NULL); assert (res == 0); } while (1) sleep (1); return 0; } GDB output for program 1: Reading symbols from //gdb_tests/continue-pending-status_exit_test... (gdb) r Starting program: /gdb_tests/continue-pending-status_exit_test More threads Hello World Hello World Hello World Hello World Hello World Hello World [New Thread 258 (tid 28115345)] [Thread 258 (tid 28115345) exited] [New Thread 515 (tid 27001289)] [Thread 515 (tid 27001289) exited] [New Thread 772 (tid 19136771)] [Thread 772 (tid 19136771) exited] [New Thread 1029 (tid 18612569)] [Thread 1029 (tid 18612569) exited] [New Thread 1286 (tid 31457595)] [Thread 1286 (tid 31457595) exited] [New Thread 1543 (tid 30736823)] [Thread 1543 (tid 30736823) exited] Thread 1 received signal SIGINT, Interrupt. 0xd0611d70 in _p_nsleep () from /usr/lib/libpthread.a(_shr_xpg5.o) (gdb) info threads Id Target Id Frame * 1 Thread 1 (tid 25231793) ([running]) 0xd0611d70 in _p_nsleep () from /usr/lib/libpthread.a(_shr_xpg5.o) Program 2: This file was written by Chris Demetriou (cgd@google.com). */ /* Simple test to trigger thread events (thread start, thread exit). */ #include #include #include static void * threadfunc (void *arg) { printf ("in threadfunc\n"); return NULL; } static void after_join_func (void) { printf ("finished\n"); } int main (int argc, char *argv[]) { pthread_t thread; if (pthread_create (&thread, NULL, threadfunc, NULL) != 0) { printf ("pthread_create failed\n"); exit (1); } if (pthread_join (thread, NULL) != 0) { printf ("pthread_join failed\n"); exit (1); } after_join_func (); return 0; } From: Aditya Vidyadhar Kamath Date: Thursday, 2 May 2024 at 8:01 PM To: tom@tromey.com Cc: Ulrich Weigand , gdb-patches@sourceware.org , Aditya Kamath1 , Sangamesh Mallayya , jhb@freebsd.org Subject: [EXTERNAL] [PATCH v3] [RFC] Fix AIX thread exit events not being reported and UI to show kernel thread ID. From: Aditya Vidyadhar Kamath In AIX when a thread exits we were not showing that a thread exit event happened and GDB continued to keep the terminated threads. If we have terminated threads then the UI on info threads command will look like (gdb) info threads Id Target Id Frame * 1 Thread 1 (tid 26607979, running) 0xd0611d70 in _p_nsleep () from /usr/lib/libpthreads.a(_shr_xpg5.o) 2 Thread 258 (tid 30998799, finished) aix-thread: ptrace (52, 30998799) returned -1 (errno = 3 The process does not exist.) If we see the frame is not getting displayed correctly. The reason for the same is that in AIX we were not managing thread states. In particular we do not know when a thread terminates. The reason being in sync_threadlists () the pbuf and gbuf lists remain the same though certain threads exit. This patch is a fix to the same. Also certain UI is changed. On a new thread born and exit the UI in AIX will be similar to Linux with both user and kernel thread information. [New Thread 258 (tid 32178533)] [New Thread 515 (tid 30343651)] [New Thread 772 (tid 33554909)] [New Thread 1029 (tid 24969489)] [New Thread 1286 (tid 18153945)] [New Thread 1543 (tid 30736739)] [Thread 258 (tid 32178533) exited] [Thread 515 (tid 30343651) exited] [Thread 772 (tid 33554909) exited] [Thread 1029 (tid 24969489) exited] [Thread 1286 (tid 18153945) exited] [Thread 1543 (tid 30736739) exited] and info threads will look like (gdb) info threads Id Target Id Frame * 1 Thread 1 (tid 31326579) ([running]) 0xd0611d70 in _p_nsleep () from /usr/lib/libpthread.a(_shr_xpg5.o) --- gdb/aix-thread.c | 248 ++++++++++++++++------------------------------- 1 file changed, 81 insertions(+), 167 deletions(-) diff --git a/gdb/aix-thread.c b/gdb/aix-thread.c index c70bd82bc24..bd74c0c805b 100644 --- a/gdb/aix-thread.c +++ b/gdb/aix-thread.c @@ -55,6 +55,7 @@ #include #include #include +#include #if !HAVE_DECL_GETTHRDS extern int getthrds (pid_t, struct thrdsinfo64 *, int, tid_t *, int); @@ -190,6 +191,12 @@ struct aix_thread_variables /* Whether the current architecture is 64-bit. Only valid when pd_able is true. */ int arch64; + + /* Describes the number of thread exit events reported. */ + std::unordered_set exited_threads; + + /* Describes if thread is still in queue and not in unknown state. */ + std::vector in_queue_threads; }; /* Key to our per-inferior data. */ @@ -737,47 +744,6 @@ state2str (pthdb_state_t state) } } -/* qsort() comparison function for sorting pd_thread structs by pthid. */ - -static int -pcmp (const void *p1v, const void *p2v) -{ - struct pd_thread *p1 = (struct pd_thread *) p1v; - struct pd_thread *p2 = (struct pd_thread *) p2v; - return p1->pthid < p2->pthid ? -1 : p1->pthid > p2->pthid; -} - -/* ptid comparison function */ - -static int -ptid_cmp (ptid_t ptid1, ptid_t ptid2) -{ - if (ptid1.pid () < ptid2.pid ()) - return -1; - else if (ptid1.pid () > ptid2.pid ()) - return 1; - else if (ptid1.tid () < ptid2.tid ()) - return -1; - else if (ptid1.tid () > ptid2.tid ()) - return 1; - else if (ptid1.lwp () < ptid2.lwp ()) - return -1; - else if (ptid1.lwp () > ptid2.lwp ()) - return 1; - else - return 0; -} - -/* qsort() comparison function for sorting thread_info structs by pid. */ - -static int -gcmp (const void *t1v, const void *t2v) -{ - struct thread_info *t1 = *(struct thread_info **) t1v; - struct thread_info *t2 = *(struct thread_info **) t2v; - return ptid_cmp (t1->ptid, t2->ptid); -} - /* Search through the list of all kernel threads for the thread that has stopped on a SIGTRAP signal, and return its TID. Return 0 if none found. */ @@ -822,22 +788,16 @@ static void sync_threadlists (pid_t pid) { int cmd, status; - int pcount, psize, pi, gcount, gi; - struct pd_thread *pbuf; - struct thread_info **gbuf, **g, *thread; pthdb_pthread_t pdtid; pthread_t pthid; pthdb_tid_t tid; process_stratum_target *proc_target = current_inferior ()->process_target (); struct aix_thread_variables *data; data = get_thread_data_helper_for_pid (pid); - + pthdb_state_t state; + data->in_queue_threads.clear (); /* Accumulate an array of libpthdebug threads sorted by pthread id. */ - pcount = 0; - psize = 1; - pbuf = XNEWVEC (struct pd_thread, psize); - for (cmd = PTHDB_LIST_FIRST;; cmd = PTHDB_LIST_NEXT) { status = pthdb_pthread (data->pd_session, &pdtid, cmd); @@ -848,118 +808,68 @@ sync_threadlists (pid_t pid) if (status != PTHDB_SUCCESS || pthid == PTHDB_INVALID_PTID) continue; - if (pcount == psize) - { - psize *= 2; - pbuf = (struct pd_thread *) xrealloc (pbuf, - psize * sizeof *pbuf); - } - pbuf[pcount].pdtid = pdtid; - pbuf[pcount].pthid = pthid; - pcount++; - } - - for (pi = 0; pi < pcount; pi++) - { - status = pthdb_pthread_tid (data->pd_session, pbuf[pi].pdtid, &tid); - if (status != PTHDB_SUCCESS) - tid = PTHDB_INVALID_TID; - pbuf[pi].tid = tid; - } - - qsort (pbuf, pcount, sizeof *pbuf, pcmp); - - /* Accumulate an array of GDB threads sorted by pid. */ - - /* gcount is GDB thread count and pcount is pthreadlib thread count. */ + ptid_t ptid (pid, 0, pthid); + status = pthdb_pthread_state (data->pd_session, pdtid, &state); + data->in_queue_threads.push_back (pdtid); - gcount = 0; - for (thread_info *tp : all_threads (proc_target, ptid_t (pid))) - gcount++; - g = gbuf = XNEWVEC (struct thread_info *, gcount); - for (thread_info *tp : all_threads (proc_target, ptid_t (pid))) - *g++ = tp; - qsort (gbuf, gcount, sizeof *gbuf, gcmp); - - /* Apply differences between the two arrays to GDB's thread list. */ - - for (pi = gi = 0; pi < pcount || gi < gcount;) - { - if (pi == pcount) + /* If this thread has reported and exited, do not add it again. */ + if (state == PST_TERM) { - delete_thread (gbuf[gi]); - gi++; + if (data->exited_threads.count (pdtid) != 0) + continue; } - else if (gi == gcount) - { - aix_thread_info *priv = new aix_thread_info; - priv->pdtid = pbuf[pi].pdtid; - priv->tid = pbuf[pi].tid; - - thread = add_thread_with_info (proc_target, - ptid_t (pid, 0, pbuf[pi].pthid), - private_thread_info_up (priv)); - pi++; - } - else + /* If this thread has never been reported to GDB, add it. */ + if (!in_thread_list (proc_target, ptid)) { - ptid_t pptid, gptid; - int cmp_result; - - pptid = ptid_t (pid, 0, pbuf[pi].pthid); - gptid = gbuf[gi]->ptid; - pdtid = pbuf[pi].pdtid; - tid = pbuf[pi].tid; - - cmp_result = ptid_cmp (pptid, gptid); - - if (cmp_result == 0) - { - aix_thread_info *priv = get_aix_thread_info (gbuf[gi]); - - priv->pdtid = pdtid; - priv->tid = tid; - pi++; - gi++; - } - else if (cmp_result > 0) + aix_thread_info *priv = new aix_thread_info; + /* init priv */ + priv->pdtid = pdtid; + status = pthdb_pthread_tid (data->pd_session, pdtid, &tid); + priv->tid = tid; + /* Check if this is the main thread. If it is, then change + its ptid and add its private data. */ + if (get_signaled_thread (pid) == tid + && in_thread_list (proc_target, ptid_t (pid))) { - /* This is to make the main process thread now look - like a thread. */ - - if (gptid.is_pid ()) - { - thread_info *tp = proc_target->find_thread (gptid); - thread_change_ptid (proc_target, gptid, pptid); - aix_thread_info *priv = new aix_thread_info; - priv->pdtid = pbuf[pi].pdtid; - priv->tid = pbuf[pi].tid; - tp->priv.reset (priv); - gi++; - pi++; - } - else - { - delete_thread (gbuf[gi]); - gi++; - } + thread_info *tp = proc_target->find_thread (ptid_t (pid)); + thread_change_ptid (proc_target, ptid_t (pid), ptid); + tp->priv.reset (priv); } else - { - thread = add_thread (proc_target, pptid); + add_thread_with_info (proc_target, ptid, + private_thread_info_up (priv)); + } - aix_thread_info *priv = new aix_thread_info; - thread->priv.reset (priv); - priv->pdtid = pdtid; - priv->tid = tid; - pi++; - } + /* The thread is terminated. Remove it. */ + if (state == PST_TERM) + { + thread_info *thr = proc_target->find_thread (ptid); + gdb_assert (thr != nullptr); + delete_thread (thr); + data->exited_threads.insert (pdtid); } } - xfree (pbuf); - xfree (gbuf); + /* Sometimes there can be scenarios where the thread status is + unknown and we it will never iterate in the for loop above, + since cmd will be no longer be pointing to that threads. One + such scenario is the gdb.threads/thread_events.exp testcase + where in the end after the threadfunc breakpoint is hit, the + thread exits and gets into a PST_UNKNOWN state. So this thread + will not run in the above for loop. Therefore the below for loop + is to manually delete such threads. */ + for (struct thread_info *it : all_threads ()) + { + aix_thread_info *priv = get_aix_thread_info (it); + auto itr = std::find (data->in_queue_threads.begin (), + data->in_queue_threads.end (), priv->pdtid); + if (itr == data->in_queue_threads.end ()) + { + delete_thread (it); + data->exited_threads.insert (priv->pdtid); + } + } } /* Iterate_over_threads() callback for locating a thread, using @@ -1013,8 +923,8 @@ pd_update (pid_t pid) } /* Try to start debugging threads in the current process. - If successful and there exists and we can find an event thread, return a ptid - for that thread. Otherwise, return a ptid-only ptid using PID. */ + If successful and there exists and we can find an event thread, set + pd_active for that thread. Otherwise, return. */ static void pd_activate (pid_t pid) @@ -2084,10 +1994,17 @@ aix_thread_target::thread_alive (ptid_t ptid) std::string aix_thread_target::pid_to_str (ptid_t ptid) { - if (ptid.tid () == 0) - return beneath ()->pid_to_str (ptid); + thread_info *thread_info = current_inferior ()->find_thread (ptid); - return string_printf (_("Thread %s"), pulongest (ptid.tid ())); + if (thread_info != NULL && thread_info->priv != NULL) + { + aix_thread_info *priv = get_aix_thread_info (thread_info); + + return string_printf (_("Thread %s (tid %s)"), pulongest (ptid.tid ()), + pulongest (priv->tid)); + } + + return beneath ()->pid_to_str (ptid); } /* Return a printable representation of extra information about @@ -2098,7 +2015,6 @@ aix_thread_target::extra_thread_info (struct thread_info *thread) { int status; pthdb_pthread_t pdtid; - pthdb_tid_t tid; pthdb_state_t state; pthdb_suspendstate_t suspendstate; pthdb_detachstate_t detachstate; @@ -2115,33 +2031,31 @@ aix_thread_target::extra_thread_info (struct thread_info *thread) aix_thread_info *priv = get_aix_thread_info (thread); pdtid = priv->pdtid; - tid = priv->tid; - - if (tid != PTHDB_INVALID_TID) - /* i18n: Like "thread-identifier %d, [state] running, suspended" */ - buf.printf (_("tid %d"), (int)tid); status = pthdb_pthread_state (data->pd_session, pdtid, &state); + + /* Output should look like Thread %d (tid %d) ([state]). */ + /* Example:- Thread 1 (tid 34144587) ([running]). */ + /* where state can be running, idle, sleeping, finished, + suspended, detached, cancel pending, ready or unknown. */ + if (status != PTHDB_SUCCESS) state = PST_NOTSUP; - buf.printf (", %s", state2str (state)); + buf.printf ("[%s]", state2str (state)); status = pthdb_pthread_suspendstate (data->pd_session, pdtid, &suspendstate); if (status == PTHDB_SUCCESS && suspendstate == PSS_SUSPENDED) - /* i18n: Like "Thread-Id %d, [state] running, suspended" */ - buf.printf (_(", suspended")); + buf.printf (_("[suspended]")); status = pthdb_pthread_detachstate (data->pd_session, pdtid, &detachstate); if (status == PTHDB_SUCCESS && detachstate == PDS_DETACHED) - /* i18n: Like "Thread-Id %d, [state] running, detached" */ - buf.printf (_(", detached")); + buf.printf (_("[detached]")); pthdb_pthread_cancelpend (data->pd_session, pdtid, &cancelpend); if (status == PTHDB_SUCCESS && cancelpend) - /* i18n: Like "Thread-Id %d, [state] running, cancel pending" */ - buf.printf (_(", cancel pending")); + buf.printf (_("[cancel pending]")); buf.write ("", 1); -- 2.41.0