Date: Mon, 24 May 2004 11:14:55 +0200 From: Wim Rijnders <wim@mediamessage.nl> To: freebsd-net@freebsd.org Subject: netgraph: kernel panic due to M_DONTWAIT when connecting ksocket Message-ID: <1085390095.633.26.camel@crazyharry>
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Hello,
When trying to use a netgraph ksocket for a tcp connection, we get a
kernel panic on opening the connection. The panic is a result of a
KASSERT() on the value of a flag which we don't set ourselves and which
we don't appear to have control over.
Details of our investigation follow. What can we do to fix this?
---
We're using the 5.2-CURRENT release.
* We use ksockets in netgraph to create a tcp connection. The kernel
panics when creating a connection with code similar to:
result= NgSendMsg(ctrlSoc, path, NGM_KSOCKET_COOKIE,
NGM_KSOCKET_CONNECT, &addr, sizeof(addr) )
* The kernel panic occurs in ng_ksocket.c , function
ng_ksocket_incoming2() on a call to macro NG_MKMESSAGE().
This macro is defined in ng_message.h. One of the first things it does
is perform this KASSERT():
KASSERT(!(how & M_DONTWAIT), \
("NG_MKMESSAGE() with how=M_DONTWAIT (%d)\n", how)); \
* We do not set the M_DONTWAIT flag anywhere our code. The setting can
be traced to call in sowakeup(), line 320 in
/usr/src/sys/kern/uipc_socket2.c:
if (sb->sb_flags & SB_UPCALL)
sh freebeer*so->so_upcall)(so, so->so_upcallarg, M_DONTWAIT);
---
Kind regards,
Wim Rijnders
Buyways BV.
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