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Team debug effort with Michael Lotz:

Browse Source 
Tracked down the root cause of the issue worked around in r24228.
The behavior that was occurring in this case was as follows:
Vision created a BInvoker off the heap, containing a BMessage likewise
off the heap. It then called BAlert::Go with this invoker. When any of
the buttons in the BAlert were pushed, _SendMessage would enqueue the
message into the target looper (in this case, Vision's window) and wake
it up with write_port_etc. However, in some cases this would result in
a reschedule such that Vision's looper executed before _SendMessage() was
able to complete all its processing. Upon receiving this message, Vision
destroyed the BInvoker in question, which in turn deleted its owned
BMessage -- which was the message that was still in the middle of _SendMessage()!.
Consequently it would crash a few lines later when it hit IsSourceWaiting() and
tried to check flags off its header off the already destroyed this. To fix this,
we now do the AddMessage/write_port_etc last before returning. Also removed the
sanity checks added in r24228 so we don't mask other problems of similar nature.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24297 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Rene Gollent 2008-03-08 00:18:51 +00:00
parent 556f83c6f7
commit 766c46166c
1 changed files with 21 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

38
src/kits/app/Message.cpp
View File

@ -613,7 +613,7 @@ bool
BMessage::IsSourceWaiting() const
{
DEBUG_FUNCTION_ENTER;
return fHeader && (fHeader->flags & MESSAGE_FLAG_REPLY_REQUIRED)
return (fHeader->flags & MESSAGE_FLAG_REPLY_REQUIRED)
&& !(fHeader->flags & MESSAGE_FLAG_REPLY_DONE);
}
@ -622,7 +622,7 @@ bool
BMessage::IsSourceRemote() const
{
DEBUG_FUNCTION_ENTER;
return fHeader && (fHeader->flags & MESSAGE_FLAG_WAS_DELIVERED)
return (fHeader->flags & MESSAGE_FLAG_WAS_DELIVERED)
&& (fHeader->reply_team != BPrivate::current_team());
}
@ -1953,21 +1953,7 @@ BMessage::_SendMessage(port_id port, team_id portOwner, int32 token,
header->reply_target = replyToPrivate.Token();
header->flags |= MESSAGE_FLAG_WAS_DELIVERED;
if (direct != NULL) {
KTRACE("BMessage send direct: port: %ld, token: %ld, "
"message: '%c%c%c%c'", port, token,
char(what >> 24), char(what >> 16), char(what >> 8), (char)what);
// this is a local message transmission
direct->AddMessage(copy);
if (direct->Queue()->IsNextMessage(copy) && port_count(port) <= 0) {
// there is currently no message waiting, and we need to wakeup the looper
write_port_etc(port, 0, NULL, 0, B_RELATIVE_TIMEOUT, 0);
}
direct->Release();
} else {
if (direct == NULL) {
KTRACE("BMessage send remote: team: %ld, port: %ld, token: %ld, "
"message: '%c%c%c%c'", portOwner, port, token,
char(what >> 24), char(what >> 16), char(what >> 8), (char)what);
@ -1984,6 +1970,24 @@ BMessage::_SendMessage(port_id port, team_id portOwner, int32 token,
fHeader->flags |= MESSAGE_FLAG_REPLY_DONE;
}
// we need to do this last because it is possible our
// message might be destroyed after it's enqueued in the
// target looper. Thus we don't want to do any ops that depend on
// members of this after the enqueue.
if (direct != NULL) {
KTRACE("BMessage send direct: port: %ld, token: %ld, "
"message: '%c%c%c%c'", port, token,
char(what >> 24), char(what >> 16), char(what >> 8), (char)what);
// this is a local message transmission
direct->AddMessage(copy);
if (direct->Queue()->IsNextMessage(copy) && port_count(port) <= 0) {
// there is currently no message waiting, and we need to wakeup the looper
write_port_etc(port, 0, NULL, 0, B_RELATIVE_TIMEOUT, 0);
}
direct->Release();
}
free(buffer);
return result;
}