Stack backtrace

Robert Watson rwatson at
Fri Jun 18 20:05:59 GMT 2004

On Fri, 18 Jun 2004, Grover Lines wrote:

> I've been having some problems with cvsup corruption and haven't been
> able to trace it to the source so I decided to recompile my kernel with
> all GENERIC options and debugging to see if it was something that I had
> changed that caused the problem. I'm not sure what this means but it
> popped up during the build of cvsup. 
> Is this a possible source of my problem or is this something not to
> worry about? 

This is unlikely to be the cause of the problem you're experiencing, but
it's also not something to be ignored.  Basically, we're grabbing the
inpcb lock over a potentially blocking memory allocation, which is a Bad
Thing (tm).  However, it's a non-trivial fix because it requires some code
plumbing.  I'll work up a patch and see what I can do, but it sounds like
you need to keep looking to find the problem that's actually causing it. 

Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
robert at      Senior Research Scientist, McAfee Research

> malloc(M_WAITOK) of "Mbuf", forcing M_NOWAIT with the following
> non-sleepable locks held:
> exclusive sleep mutex inp (tcpinp) r = 0 (0xc1d17bd0) locked @
> /usr/src/sys/netinet/tcp_usrreq.c:1037
> Stack backtrace:
> witness_warn(5,0,c08db91d,c08c1095,c08c5805) at witness_warn+0x194
> uma_zalloc_arg(c1021b00,d6b19c0c,2,c066635e,0) at uma_zalloc_arg+0x50
> ip_ctloutput(c284213c,d6b19cb8,c08ce5cb,40e,c1d17bd0) at ip_ctloutput+0x9b
> tcp_ctloutput(c284213c,d6b19cb8,0,0,0) at tcp_ctloutput+0xad
> sosetopt(c284213c,d6b19cb8,d6b19cb4,0,c284213c) at sosetopt+0x48
> setsockopt(c1d4ddc0,d6b19d14,14,d6b19d48,5) at setsockopt+0xd4
> syscall(2f,2f,2f,281a6920,3) at syscall+0x12f
> Xint0x80_syscall() at Xint0x80_syscall+0x1f
> --- syscall (105), eip = 0x28108fef, esp = 0xbfbfe91c, ebp = 0xbfbfe948 ---
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