Subject: kern/36658: systrace locks the system
To: None <,,>
From: None <>
List: netbsd-bugs
Date: 07/16/2007 14:00:01
>Number:         36658
>Category:       kern
>Synopsis:       systrace locks the system
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 16 14:00:00 +0000 2007
>Originator:     Julio M. Merino Vidal
>Release:        NetBSD 4.99.23
System: NetBSD vm-nb-head 4.99.23 NetBSD 4.99.23 (GENERIC_DIAGNOSTIC) #2: Sun Jul 15 16:02:35 CEST 2007 i386
Architecture: i386
Machine: i386
	When running the systrace tool against a binary in the system
	(after enabling 'options SYSTRACE' in the kernel), the machine
	locks up.  I cannot cancel the systrace command nor do anything
	else, except type characters which are not recognized by the
	system.  For example, characters will keep appearing on the
	console where I ran systrace, but if I switch to a different
	virtual terminal and try to log in, the key presses are not

	If I later enter ddb and ask for a 'sync', the kernel spits out
	a diagnostic assertion about locking.  Maybe, just maybe, this
	problem has been introducing with ad@'s work.  But I really don't

	I'm not marking this as critical nor serious because systrace is
	not enabled by default and supposedly it doesn't work correctly
	(or at least that's what I recall hearing).
	Trivial.  Build a kernel with 'options SYSTRACE' support and
	preferably 'options DIAGNOSTIC' too and run 'systrace /bin/ls'.
	I doubt that command is correct anyway, but it is enough to expose
	the problem.


	vm-nb-head:~> systrace /bin/ls
	Error: Can't open display:
	systrace: EOF on policy input request: No such file or directory
	... here I hit ctrl+alt+esc ...
	Stopped in pid 456.1 (systrace) at netbsd:cpu_Debugger+0x4: popl %ebp
	db> sync
	syncing disks... panic: kernel diagnostic assertion "lwp_locked(l, &l->l_cpu->ci_schedstate.spc_lwplock)" failed: file "/Volumes/NetBSD/src/sys/kern/kern_synch.c", line 305
	Stopped in pid 456.1 (systrace) at netbsd:cpu_Debugger+0x4: popl %ebp
	Don't know.