[Mono-bugs] [Bug 82286][Nor] Changed - Assertion in new "small thread id" code

[bugzilla-daemon at bugzilla.ximian.com]

Please do not reply to this email- if you want to comment on the bug, go to the
URL shown below and enter your comments there.

Changed by mark.probst at gmail.com.

http://bugzilla.ximian.com/show_bug.cgi?id=82286

--- shadow/82286	2007-08-08 13:46:07.000000000 -0400
+++ shadow/82286.tmp.6633	2007-08-09 05:14:57.000000000 -0400
@@ -138,6 +138,106 @@
 aborting...
 
 ------- Additional Comments From vargaz at gmail.com  2007-08-08 13:46 -------
 The ExecutionContext crash is caused by sharing the execution context
 object between appdomains in the Thread class.
 
+
+------- Additional Comments From mark.probst at gmail.com  2007-08-09 05:14 -------
+I think I've found out why thread_cleanup is sometimes called twice
+for the same thread object, but I'm not sure it's a problem, and if it
+is, I'm not sure how to fix it.  I've turned on thread debug output
+and added printing the pointers to the thread objects whenever
+possible.  This is the end of one such log:
+
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaafb55dc0
+** Message: mono_thread_current: returning 0x2aaaafb55dc0
+** Message: mono_thread_current: returning 0x2aaaafb55dc0
+** Message: mono_thread_exit: mono_thread_exit for 0x2aaaafb55dc0
+(1107700032)
+** Message: handle_remove: thread ID 1107700032
+** Message: mono_thread_current: returning 0x2aaaafb55dc0
+** Message: ves_icall_System_Threading_Thread_Thread_internal: Trying
+to start a new thread: this (0x2aaaafb558c0) start (0x2aaaafe765a0)
+** Message: mono_thread_start: (46912510896944) Launching thread
+0x2aaaafb558c0 (1107700032)
+** Message: handle_store: thread 0x2aaaafb558c0 ID 1107700032
+** Message: mono_thread_start: (46912510896944) waiting for thread
+0x2aaaafb558c0 (1107700032) to start
+** Message: start_wrapper: (1107700032) Start wrapper
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: start_wrapper: (1107700032) Setting current_object_key to
+0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_start: (46912510896944) Done launching thread
+0x2aaaafb558c0 (1107700032)
+** Message: ves_icall_System_Threading_Thread_Thread_internal: Started
+thread ID 1107700032 (handle 0x9c1)
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaafb558c0
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: mono_thread_current: returning 0x2aaaaaaeac40
+** Message: ves_icall_System_Threading_Thread_Thread_internal: Trying
+to start a new thread: this (0x2aaaafb55780) start (0x2aaaafaa7b40)
+** Message: mono_thread_start: (46912510896944) Launching thread
+0x2aaaafb55780 (1109866816)
+** Message: handle_store: thread 0x2aaaafb55780 ID 1109866816
+** Message: mono_thread_start: (46912510896944) waiting for thread
+0x2aaaafb55780 (1109866816) to start
+** Message: start_wrapper: (1109866816) Start wrapper
+** Message: mono_thread_current: returning 0x2aaaafb55780
+** Message: mono_thread_current: returning 0x2aaaafb55780
+** Message: mono_thread_current: returning 0x2aaaafb55780
+** Message: mono_thread_current: returning 0x2aaaafb55780
+** Message: start_wrapper: (1109866816) Setting current_object_key to
+0x2aaaafb55780
+** Message: mono_thread_current: returning 0x2aaaafb55780
+** Message: mono_thread_start: (46912510896944) Done launching thread
+0x2aaaafb55780 (1109866816)
+** Message: ves_icall_System_Threading_Thread_Thread_internal: Started
+thread ID 1109866816 (handle 0x9c3)
+** Message: wait_for_tids: cleaning up after thread 0x2aaaafb55dc0
+(1107700032)
+** Message: handle_remove: thread ID 1107700032
+** Message: mono_thread_current: returning (nil)
+
+** ERROR **: file threads.c: line 340 (small_id_free): assertion
+failed: (id >= 0 && id < small_id_table_size)
+aborting...
+
+Note the first mono_thread_exit there:
+
+** Message: mono_thread_exit: mono_thread_exit for 0x2aaaafb55dc0
+(1107700032)
+** Message: handle_remove: thread ID 1107700032
+
+Then note the creation of a new thread with the same tid, but a
+different thread object:
+
+** Message: mono_thread_start: (46912510896944) Launching thread
+0x2aaaafb558c0 (1107700032)
+
+Then, at the end, note how the old thread object suddenly shows up again:
+
+** Message: wait_for_tids: cleaning up after thread 0x2aaaafb55dc0
+(1107700032)
+
+The reason for this seems to be that wait_for_tids() uses no locking
+and it can happen that after it has successfully looked up a tid in
+the threads hash and deemed it safe to clean that thread up, that
+thread exits by itself, but before wait_for_tids() has cleaned it up,
+so the cleanup is done twice.
+
+Again, I'm not sure this is a problem, and I'm not sure how to
+appropriately do locking there if it is.  Can anybody shed some light
+on this?