On Sat, Dec 07, 2002 at 08:58:26AM -0500, Robert Watson wrote: > On Fri, 6 Dec 2002, Kris Kennaway wrote: > > > On Fri, Dec 06, 2002 at 07:18:03PM -0800, Lars Eggert wrote: > > > > > >I'm getting this too: > > > > After discussing this with various people on IRC, it was determined that > > this is not the place where the reversal is occurring, but since witness > > doesn't have the lock order defined it has to guess, and in this > > instance it is guessing the wrong way around. After adding the lock > > order to subr_witness.c I now get this: > > Yeah, we're exchanging some out-of-band e-mail on this: the basic problem > is that: > > filedesc>pipe > pipe>sigio > sigio>proc > proc>filedesc > > We're talking about some possible solutions, including deferred > signalling, etc, etc.
Here's another panic I got overnight:
lock order reversal
1st 0xc4cbcd80 pipe mutex (pipe mutex) @ /local0/src-client/sys/kern/sys_pipe.c:465
2nd 0xc044e780 sigio lock (sigio lock) @ /local0/src-client/sys/kern/kern_sig.c:2225
Debugger("witness_lock")
Stopped at Debugger+0x54: xchgl %ebx,in_Debugger.0
db> trace
Debugger(c03efc85,c044e780,c04141a3,c04141a3,c0416b5c) at Debugger+0x54
witness_lock(c044e780,8,c0416b5c,8b1,c4cbcd80) at witness_lock+0x667
_mtx_lock_flags(c044e780,0,c0416b5c,8b1,23) at _mtx_lock_flags+0xb1
pgsigio(c5cf3cf8,17,0,1ad,0) at pgsigio+0x30
pipe_read(c63b2c6c,d9539c7c,c4e91f00,0,c67608c0) at pipe_read+0x516
dofileread(c67608c0,c63b2c6c,4,bfbff533,1) at dofileread+0xd2
read(c67608c0,d9539d10,c043094c,407,3) at read+0x6b
syscall(2f,2f,2f,0,bfbff534) at syscall+0x28e
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (3, FreeBSD ELF32, read), eip = 0x2812d1c8, esp = 0xbfbff500, ebp =
0xbfbff700 ---
db>
Kris
msg48337/pgp00000.pgp
Description: PGP signature
