Re: Re: SIGTRAP after writing to socket
Re: Re: SIGTRAP after writing to socket
- Subject: Re: Re: SIGTRAP after writing to socket
- From: "Martin Redington" <email@hidden>
- Date: Thu, 16 Nov 2006 18:48:59 +0000
Funny that this should crop up here - I'm looking at a crash that
manifests itself as a SIGTRAP, and debugger traces indicate that this
is indeed hitting an int3 instruction on intel, and a trap instruction
on PPC.
The crash appears to be in CFRunLoop, specifically in __CFRunLoopFindMode
I don't think its the same as yours - mine seems to be related to the
use of Distributed Objects, and is on 10.4 (although it may well be
present on 10.3).
However, it only seems to manifest itself after a large number of
threads have been created, and is very hard to reproduce normally
(although we have test cases that will reliably get it) - if yours is
like this, its possible that you just haven't hit it on 10.4 yet.
Interestingly I can get the crash with (a variant of) the
SimpleThreads example, whose original author was ... Quinn "The
Eskimo!" (http://www.mildmanneredindustries.com/downloads/SimpleThreadsCrashes.dmg)
cheers,
Martin
Further details available at:
http://www.cocoabuilder.com/archive/message/cocoa/2006/11/14/174438
http://www.cocoadev.com/index.pl?DistributedObjectsForInterThreadCommsCrash
On 11/16/06, Quinn <email@hidden> wrote:
At 8:33 -0800 15/11/06, Stefan Werner wrote:
>It does, that is exactly what's puzzling me. The crash log mentions
>EXC_BREAKPOINT.
That's because of the way that CrashReporter works. It catches the
Mach exception (EXC_BREAKPOINT), generates the crash log, and then
forwards the exception to the next handler in the chain. In this
case, the next handler is the BSD subsystem within the kernel, hich
reflects the exception back into the process as the appropriate BSD
signal (SIGTRAP).
Given that there's no debugger involved, the other place I've seen
these sort of exceptions is when certain pieces of system software
'panic'. For example, CF's HALT macro (used when it detects that
things are completely messed up) expands to a breakpoint instruction
("trap" on PPC, "int3" on Intel). dyld does the same thing. Usually
when this happens you get a message on the console that explains what
happened. Do you see anything like this?
Failing that, please post the crash log.
S+E
--
Quinn "The Eskimo!" <http://www.apple.com/developer/>
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
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