RE: Fw: RE: [PATCH] Fix assert pid != 0 assertion failure in AIX

[Aditya Vidyadhar Kamath <ADITYA.VIDYADHAR.KAMATH@ibm.com>]

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Morning Simon.

The reason we were adding one more inferior_ptid!= 0 , condition is the previous condition in the and logic i.e. pid != inferior_ptd.pid() will satisfy as -1 is not equal to 0. [inferior_ptid is set to null before coming into wait]. So, in the next iteration since the process has exited waitpid (), will lead to ERRCHILD error though the current iteration fetched the right pid using waitpid ().

However, we get your point that inferior_ptid should not be used initially [for any condition check till we fetch the pid using waitpid ()] as it is being reset.

Please find attached our modified patch where we do a check of the inferior being in the list. I hope this solution matches to what you suggested.

[See 0001-Fix-gdb_assert-pid-0-assertion-failure-in-AIX.patch file attached to this email]

Have a great day.

Thanks and regards,
Aditya.


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From a1c5ab5338a5d46eab675a85c28a9b00256d395a Mon Sep 17 00:00:00 2001
From: "aditya@ibm" <aditya.vidyadhar.kamath@ibm.com>
Date: Tue, 5 Jul 2022 23:05:18 -0500
Subject: [PATCH] Fix gdb_assert (pid != 0); assertion failure in AIX

---
 gdb/aix-thread.c     | 2 ++
 gdb/rs6000-aix-nat.c | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/gdb/aix-thread.c b/gdb/aix-thread.c
index ecd8200b692..e5c287a3fad 100644
--- a/gdb/aix-thread.c
+++ b/gdb/aix-thread.c
@@ -1091,6 +1091,8 @@ aix_thread_target::wait (ptid_t ptid, struct target_waitstatus *status,
   if (ptid.pid () == -1)
     return ptid_t (-1);
 
+  inferior_ptid = ptid;
+
   /* Check whether libpthdebug might be ready to be initialized.  */
   if (!pd_active && status->kind () == TARGET_WAITKIND_STOPPED
       && status->sig () == GDB_SIGNAL_TRAP)
diff --git a/gdb/rs6000-aix-nat.c b/gdb/rs6000-aix-nat.c
index 8563aea313a..24071a3742f 100644
--- a/gdb/rs6000-aix-nat.c
+++ b/gdb/rs6000-aix-nat.c
@@ -525,11 +525,11 @@ rs6000_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
 
 	  /* Claim it exited with unknown signal.  */
 	  ourstatus->set_signalled (GDB_SIGNAL_UNKNOWN);
-	  return inferior_ptid;
+	  return ptid_t(pid);
 	}
 
       /* Ignore terminated detached child processes.  */
-      if (!WIFSTOPPED (status) && pid != inferior_ptid.pid ())
+      if (!WIFSTOPPED (status) && find_inferior_pid(this,pid) == NULL)
 	pid = -1;
     }
   while (pid == -1);
-- 
2.31.1