Bug 21925

 Hi Greg,
 
 Would you mind taking a look at this please?  We've got serious
 stability problems with two machines (that are overdue as production
 servers.)  I initially thought that the problem lay with ahc, but
 Justin thinks that it's vinum.
 
 Thanks,
 Joe
 
 On Tue, Oct 10, 2000 at 07:07:42PM +0000, Justin T. Gibbs wrote:
 > >	Rsyncing a remote machine's data onto this machine's
 > >	vinum drive causes the machine to bus error.
 > >
 > >	This is repeatable, and occurs on two exactly similar machines.
 > >
 > >
 > >Fatal trace 12: page fault while in kernel mode
 > >fault virtual address = 0xbfc00000
 > >fault code = supervisor read, page not present
 > >intruction pointer = 0x8:0xc0210222
 > >stack pointer = 0x10:0xc025e55c
 > >frame pointer = 0x10:0xc025e708
 > >code segment = base rx0, limit 0xfffff, type 0x1b
 > >        = DPL 0, pres 1, def32 1, gran 1
 > >processor eflags = interrupt enabled, resume, IOPL = 0
 > >current process = Idle
 > >interrupt mask =
 > >kernel: type 12 trap, code=0
 > >
 > >stopped at: bus_dmamap_load+0x1ca: movl PTmap(,%eax,4),%edx
 > >
 > >db>trace
 > >bus_dmamap_load(c1e5cdc0,c0290700,0,0,c013af88,c1e5e9cc,0) at bus_dmamap_load+
 > 				   ^<==== Buffer Pointer
 > 
 > Vinum is passing a buffer with a NULL b_data pointer to the DA driver.
 > The first time the CAM stack will reference this pointer just happens
 > to be in the ahc driver's call to bus_dmamap_load().
 > 
 > --
 > Justin
 
 -- 
 Josef Karthauser	FreeBSD: How many times have you booted today?
 Technical Manager	Viagra for your server (http://www.uk.freebsd.org)
 Pavilion Internet plc.  [joe@pavilion.net, joe@uk.freebsd.org, joe@tao.org.uk]