Hello,
I have written a small device driver for a static ram
based disk. The code is - more or less - derived from
Poul Henning Kamp's md device.
It is written for FreeBSD 4.X.
This device is kld-loaded and runs without any problems
with my 'standard' kernel configuration.
As soon as I boot a kernel with some debug settings the
driver crashes due to a failed assertion in my strategy
routine.
********
Here are the diffs between my standard(-) and debug(+) kernel configuration:
+options DDB
+options DEBUG_LOCKS
+options KBDIO_DEBUG
+options SC_DEBUG_LEVEL=5
-options PANIC_REBOOT_WAIT_TIME=5
+options PANIC_REBOOT_WAIT_TIME=60
-options SC_DISABLE_DDBKEY
+options SC_HISTORY_SIZE=1000
-device sio0 at isa? port IO_COM1 flags 0x10 irq 4
+device sio0 at isa? port IO_COM1 flags 0x90 irq 4
Some of the common options are
HZ=400, DEVICE_POLLING, KTRACE, NO_SWAPPING, SOFTUPDATES, UFS_DIRHASH
********
Here is my debugging output:
(kgdb) bt
#1 0xc0153318 in panic (fmt=0xc0cabc80 "\"sram.c\", 362: sram_strategy:
bp->b_dev==NULL")
at ../../kern/kern_shutdown.c:593
#2 0xc0cab2e8 in sram_strategy (bp=0xc349bdc0) at sram.c:362
#3 0xc015ccad in diskstrategy (bp=0xc349bdc0) at ../../kern/subr_disk.c:251
#4 0xc0224952 in dsinit (dev=0xc0ca3e80, lp=0xc0c240d0, sspp=0xc0c240cc) at
../../kern/subr_diskmbr.c:191
#5 0xc015dbfa in dsopen (dev=0xc0ca3e80, mode=8192, flags=0,
sspp=0xc0c240cc, lp=0xc0c240d0)
at ../../kern/subr_diskslice.c:696
#6 0xc015cb36 in diskopen (dev=0xc0ca3e80, oflags=1, devtype=8192,
p=0xc7bb5260) at ../../kern/subr_disk.c:196
#7 0xc018d72d in spec_open (ap=0xc8908dfc) at
../../miscfs/specfs/spec_vnops.c:193
#8 0xc018d62d in spec_vnoperate (ap=0xc8908dfc) at
../../miscfs/specfs/spec_vnops.c:119
#9 0xc01ccfb5 in ufs_vnoperatespec (ap=0xc8908dfc) at
../../ufs/ufs/ufs_vnops.c:2394
#10 0xc0189641 in vn_open (ndp=0xc8908ec8, fmode=1, cmode=385) at
vnode_if.h:189
#11 0xc01854ec in open (p=0xc7bb5260, uap=0xc8908f80) at
../../kern/vfs_syscalls.c:1035
#12 0xc02193f9 in syscall2 (frame={tf_fs = 47, tf_es = 47, tf_ds = 47,
tf_edi = 134543916,
tf_esi = -1077936648, tf_ebp = -1077936736, tf_isp = -930050092,
tf_ebx = 0, tf_edx = 134543904,
tf_ecx = -13, tf_eax = 5, tf_trapno = 0, tf_err = 2, tf_eip =
671988064, tf_cs = 31, tf_eflags = 582,
tf_esp = -1077937068, tf_ss = 47}) at ../../i386/i386/trap.c:1255
#13 0xc020c685 in Xint0x80_syscall ()
(kgdb) frame 2
(kgdb) p *bp
$2 = {b_hash = {le_next = 0xc3504000, le_prev = 0xc0286c0c}, b_vnbufs =
{tqe_next = 0x0, tqe_prev = 0x0},
b_freelist = {tqe_next = 0xc349bf18, tqe_prev = 0xc026e9e8}, b_act =
{tqe_next = 0x0, tqe_prev = 0x0},
b_flags = 1122304, b_qindex = 0, b_xflags = 0 '\000', b_lock =
{lk_interlock = {lock_data = 0},
lk_flags = 1024, lk_sharecount = 0, lk_waitcount = 0, lk_exclusivecount
= 1, lk_prio = 20,
lk_wmesg = 0xc0239afc "bufwait", lk_timo = 0, lk_lockholder = 134},
b_error = -1071408864,
b_bufsize = -1071408848, b_runningbufspace = 286, b_bcount = 0, b_resid =
512, b_dev = 0x0,
b_data = 0x200 <Address 0x200 out of bounds>, b_kvabase = 0x0, b_kvasize
= -1060487424,
b_lblkno = -1060470784, b_blkno = -1014542336, b_offset = 16384, b_iodone
= 0, b_iodone_chain = 0xffffffff,
b_vp = 0xffffffff, b_dirtyoff = 0, b_dirtyend = 0, b_rcred = 0x0, b_wcred
= 0x0, b_pblkno = 0,
b_saveaddr = 0x0, b_driver1 = 0x0, b_driver2 = 0x0, b_caller1 = 0x0,
b_caller2 = 0x0, b_pager = {
pg_spc = 0x0, pg_reqpage = 0}, b_cluster = {cluster_head = {tqh_first =
0x0, tqh_last = 0x0},
cluster_entry = {tqe_next = 0x0, tqe_prev = 0x0}}, b_pages = {0x0
<repeats 32 times>}, b_npages = 0,
b_dep = {lh_first = 0x0}, b_chain = {parent = 0x0, count = 0}}
********
And here is the source of the beginning of my strategy routine:
static void
sram_strategy (struct buf * bp)
{
intrmask_t s;
struct sram_softc * sc;
ASSERT (bp != NULL, "sram_strategy: bp==NULL");/* #1 */
ASSERT (bp->b_dev != NULL, "sram_strategy: bp->b_dev==NULL");/* #2 */
sc = bp->b_dev->si_drv1;
ASSERT (sc != NULL, "sram_strategy: bp->b_dev->si_drv1==NULL");/* #3 */
DPRINTF (9, "sram_strategy: (%p) %s %lx, %d, %ld, %p)\n",
bp,
devtoname (bp->b_dev),
bp->b_flags,
bp->b_blkno,
bp->b_bcount / DEV_BSIZE,
bp->b_data);
s = splbio ();
...
ASSERT #2 fails. Any idea?
Thank you for any help,
Norbert Koch
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