[Fwd: Re: [Sbcl-devel] Started getting memory fault in core dumps?]
Jeff Cunningham <jeffrey <at> jkcunningham.com>
2010-10-07 16:06:16 GMT
Forgot to cc the list.
-------- Forwarded Message --------
From: Jeff Cunningham <
jeffrey <at> jkcunningham.com>
To: Nikodemus Siivola <
nikodemus <at> random-state.net>
Subject: Re: [Sbcl-devel] Started getting memory fault in core dumps?
Date: Thu, 07 Oct 2010 11:48:59 -0400
Thank you for the response. I didn't know about sbcl-help so I just subscribed. Comments interspersed below:
--Jeff
-----Original Message-----
From: Nikodemus Siivola <
nikodemus <at> random-state.net>
On 7 October 2010 14:29, Jeff Cunningham wrote:
(Moving to sbcl-help.)
[lengthy explanation snipped...]
Any number of things could be causing this.
* Finalizers from before the core is saved trying to release foreign
memory allocated in the previous session. :DONT-SAVE keyword argument
to FINALIZE is for preventing that from happening. Happily, this is
easy to rule out:
(setf sb-impl::**finalizer-store** nil)
right at the start of START-THE-SERVERS. If it makes the error go
away, then it's a stale finalizer and all you need to do is to
identify where it comes from, and add :DONT-SAVE to it.
I tried this right away, of course, but it made no difference.
* Something, somewhere, may be eg. grabbing a VECTOR-SAP (the actual
memory address of vector) and trying to reuse it for the second
invocation.
* Something, somewhere, could be allocating foreign memory before the
core is saved, and blindly assuming that the foreign memory will
remain valid.
These two (and related ones) are a bit tricker to identify.
The best way is probably to try to identify just when does the memory
fault occur -- which is likely to make identifying the underlying
problem a lot easier.
First try to get a backtrace from the error:
(defun start-the-servers ()
(handler-bind ((serious-condition (lambda (c)
(declare (ignore c))
(sb-debug:backtrace))))
(stuff)))
with luck, this will set you on the right track.
Here is the backtrace I get when I try to launch the core after building in the backtrace:
starting servers
CORRUPTION WARNING in SBCL pid 13997(tid 140737353971456):
Memory fault at ae03e000 (pc=0x1000b7f955, sp=0x7ffff4c72670)
The integrity of this image is possibly compromised.
Continuing with fingers crossed.
0: (SB-DEBUG::MAP-BACKTRACE #<CLOSURE (LAMBDA #) {1004E1A009}>)[:EXTERNAL]
1: (BACKTRACE
1152921504606846975
#<SYNONYM-STREAM :SYMBOL *TERMINAL-IO* {10002DD531}>)
2: (SIGNAL #<SB-SYS:MEMORY-FAULT-ERROR {1004E19A81}>)[:EXTERNAL]
3: (ERROR SB-SYS:MEMORY-FAULT-ERROR)[:EXTERNAL]
4: (SB-SYS:MEMORY-FAULT-ERROR)
5: ("foreign function: call_into_lisp")
6: ("foreign function: post_signal_tramp")
7: (SB-IMPL::OUTPUT-BYTES/UTF-8
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
";; Swank started at port: "
NIL
0
26)
8: ((LAMBDA (&REST REST))
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
";; Swank started at port: "
NIL
0
26)
9: ((LAMBDA (&REST REST))
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
";; Swank started at port: "
NIL
0
26)[:OPTIONAL]
10: (SB-IMPL::FD-SOUT
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
";; Swank started at port: "
0
26)
11: (SB-IMPL::%WRITE-STRING
";; Swank started at port: "
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
0
NIL)
12: ((LAMBDA
(STREAM
&OPTIONAL
(#:FORMAT-ARG1072
(ERROR ??? :COMPLAINT "required argument missing" :CONTROL-STRING
"~&;; Swank started at port: ~D.~%" :OFFSET 29))
&REST SB-FORMAT::ARGS))
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
4005)
13: (FORMAT
#<SB-SYS:FD-STREAM for "standard error" {1000349001}>
#<FUNCTION (LAMBDA #) {100207E6A9}>)[:EXTERNAL]
14: (SWANK::SIMPLE-ANNOUNCE-FUNCTION 4005)
15: (SWANK::SETUP-SERVER
4005
#<FUNCTION SWANK::SIMPLE-ANNOUNCE-FUNCTION>
:SPAWN
T
"iso-latin-1-unix")
16: (WEBSERVER::START-THE-SERVERS)
17: (SB-INT:CALL-HOOKS
"initialization"
(#<FUNCTION WEBSERVER::START-THE-SERVERS>))[:EXTERNAL]
18: ((LABELS SB-IMPL::RESTART-LISP))
Error: Problem running initialization hook #<FUNCTION WEBSERVER::START-THE-SERVERS>:
Unhandled memory fault at #x2AAAAE03E000.
It looks like it has something to do with a foreign function call.
Unfortunately, there are a number of these to track down.
Regards,
Jeff
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