Subject: kern/8673:
To: None <>
From: Ross Harvey <>
List: netbsd-bugs
Date: 10/23/1999 22:15:53
>Number:         8673
>Category:       kern
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Oct 23 22:15:00 1999
>Originator:     Ross Harvey
>Release:        1.4K
	NetBSD/alpha 1.4K as of Oct 21 1998
System: NetBSD a3.hrh 1.4K NetBSD 1.4K (GENERIC) #5: Thu Sep 30 11:29:29 PDT 1999 ross@a3.hrh:/usr/src/sys/arch/alpha/compile/GENERIC alpha

	Sean Doran ( reports a panic on his alpha,
	the root cause was a misaligned access in sbdrop().
	His traceback...

	Note that the pool_get panic is secondary, the real problem is
	the misaligned access in sbdrop().

fatal kernel trap:
panic: pool_get(mbpl): free list modified: magic=0; page 0xfffffc00029ca000;
item addr 0xfffffc00029caa10

Stopped in ssh1 at      cpu_Debugger+0x4:       ret     zero,(ra)
db> t/t
cpu_Debugger() at cpu_Debugger+0x4
panic() at panic+0xec
_pool_get() at _pool_get+0x89c
tlp_rxintr() at tlp_rxintr+0x2bc
tlp_intr() at tlp_intr+0x8c
alpha_shared_intr_dispatch() at alpha_shared_intr_dispatch+0x3c
sio_iointr() at sio_iointr+0x80
interrupt() at interrupt+0x168
XentInt() at XentInt+0x1c
--- interrupt (from ipl 0) ---
esigcode() at esigcode+0x3c
XentInt() at XentInt+0x1c
--- interrupt ---
alpha_pal_swpipl() at alpha_pal_swpipl+0x4
spl0() at spl0+0x40
printf() at printf+0xd4
trap() at trap+0x574
XentUna() at XentUna+0x20
--- unaligned access fault ---
sbdrop() at sbdrop+0x98
tcp_input() at tcp_input+0x1ecc
ip_input() at ip_input+0x970
ipintr() at ipintr+0xb4
do_sir() at do_sir+0xe0
esigcode() at esigcode+0x2c
--- root of call graph ---

	I have no idea, but I've seen this too.