From owner-freebsd-current  Wed Jan 22 20:32:18 2003
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Date: Wed, 22 Jan 2003 23:33:53 -0500
From: Jake Burkholder <jake@locore.ca>
To: David Xu <davidxu@FreeBSD.ORG>
Cc: current@FreeBSD.ORG
Subject: Re: vm panic
Message-ID: <20030122233353.C58845@locore.ca>
References: <20030120224503.A1437@FreeBSD.org> <00d501c2c291$d63acf20$f001a8c0@davidw2k>
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In-Reply-To: <00d501c2c291$d63acf20$f001a8c0@davidw2k>; from davidxu@FreeBSD.ORG on Thu, Jan 23, 2003 at 11:45:13AM +0800
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Apparently, On Thu, Jan 23, 2003 at 11:45:13AM +0800,
	David Xu said words to the effect of;

> panic: lockmgr: locking against myself
> Debugger("panic")
> Stopped at Debugger+0x54: xchgl %ebx,in_Debugger.0
> db>trace
> Debugger(c0381630,c03e4ee0,c037fd14,da447c28,1) at Debugger+0x54
> panic(c037fd14,0,c037fc88,eb,1fb) at panic+0xab
> lockmgr(c138e85c,2,0,c3c150e0,c3c1514) at lockmgr+0x512
> _vm_map_lock_read(c138e280,c039bc27,896,238d3c,527) at _vm_map_lock_read+0x5a
> vm_map_check_protection(c138e80,826400,826500,2,c03b1980) at vm_map_check_protection+0x31
> useracc(8264fc4,8,2,1,c038b1f) at useracc+0x7d
> nanosleep(c3c150e0,da447d10,c039f3e,407,2) at nonosleep+0x53
> syscall(bfbf002f,804002f,826002f,bfbffbe0,804a420) at syscall+0x28e
> Xint0x80_syscall() at Xint0x80_syscall+0x1d
> --- syscall (240, FreeBSD ELF32, nanosleep), eip = 0x280b0853, esp = 0x8264fb8, ebp = 0x8264fd4
> 
> At the time, I am running ksetest, a kse based threaded program.
> Is the vm still not safe to run threaded program?
> 
> David Xu
> 

Don't know if this is the problem or not but the lockmgr code uses the
pid as the lock cookie, so it can't distinguish 2 threads from the same
process acquiring a lock.

I noticed that netbsd has fixed this for lwps.

Jake

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