9.1 panic in ccb/iscsi

[BERTRAND Joël <joel.bertrand%systella.fr@localhost>]

	Hello,

	I can see some panics on a server that exports iSCSI volumes (istgt on
a CCB device) to some workstations. dmesg always contains this kind of
backtrace :

[ 308324,087343] S-1C-1: ccb_timeout: num=1 total=1 disp=0
[ 308324,087343] uvm_fault(0xffffffff81585e20, 0x0, 2) -> e
[ 308324,087343] fatal page fault in supervisor mode
[ 308324,087343] trap type 6 code 0x2 rip 0xffffffff802280cc cs 0x8
rflags 0x10246 cr2 0x10 ilevel 0 rsp 0xffff97813fa16f48
[ 308324,087343] curlwp 0xffffc947d4f304c0 pid 0.201 lowest kstack
0xffff97813fa142c0
[ 308324,087343] panic: trap
[ 308324,087343] cpu1: Begin traceback...
[ 308324,087343] vpanic() at netbsd:vpanic+0x160
[ 308324,087343] snprintf() at netbsd:snprintf
[ 308324,087343] startlwp() at netbsd:startlwp
[ 308324,087343] alltraps() at netbsd:alltraps+0xbb
[ 308324,087343] ccb_timeout() at iscsi:ccb_timeout+0xf0
[ 308324,087343] iscsi_cleanup_thread() at iscsi:iscsi_cleanup_thread+0x2b6
[ 308324,087343] cpu1: End traceback...
[ 308324,087343] uvm_fault(0xffffc947e69898d0, 0x0, 2) -> e

[ 308324,087343] fatal page fault in supervisor mode
[ 308324,087343] dumping to dev 18,1 (offset=251919, size=4162814):
[ 308324,087343] trap type 6 code 0x2 rip 0xffffffff80979c08 cs 0x8
rflags 0x10202 cr2 0x84 ilevel 0x8d urmspp  0xffff97813e116f00
[ 308324,087343] curlwp 0xffffc947e4110b40 pid 111.14 lowest kstack
0xffff97813e1142c0
[ 308324,697557] devi000030] cpu6: package 0, core 2, smt 1

	This kernel is a regular kernel with iscsi patch (to increase iSCSI
throughput).

	Kernel doesn't enter in ddb and I don't have crash dump (why ?). But I
have a gdb kernel even if I don't know how to obtain usable information
on this kind of panic.

	Best regards,

	JKB