Date: Mon, 07 Apr 1997 17:53:51 +0200 From: Tor Egge <Tor.Egge@idi.ntnu.no> To: lampa@fee.vutbr.cz Cc: freebsd-bugs@freefall.freebsd.org Subject: Re: i386/3195: ahc panic Message-ID: <199704071553.RAA23471@pat.idt.unit.no> In-Reply-To: Your message of "Mon, 7 Apr 1997 00:20:02 -0700 (PDT)" References: <199704070720.AAA27745@freefall.freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
> Still the same problems, after some time error:
>
> ahc1:A:1: no active SCB for reconnecting target - issuing ABORT
> SAVED_TCL == 0x10
> ahc1:A:1: Target did not send an IDENTIFY message
> LASTPHAS = 0x0, SAVED_TCL = 0x10
>
> and systems loops in ahc driver, everytime I hit kernel debugger, stack is:
>
> ahc_scsi_cmd
> scsi_scsi_cmd
> sdstart
> free_xs
> scsi_done
> ahc_done
> ahc_run_done_queue
> ahc_reset_channel
>
I see the same problem with FreeBSD 3.0-current.
(kgdb) where
#0 boot (howto=260) at ../../kern/kern_shutdown.c:244
#1 0xe0118a53 in panic (fmt=0xe0101479 "from debugger")
at ../../kern/kern_shutdown.c:368
#2 0xe0101495 in db_panic (dummy1=-535016711, dummy2=0, dummy3=-1,
dummy4=0xe0202c74 "") at ../../ddb/db_command.c:440
#3 0xe0101385 in db_command (last_cmdp=0xe0203bb4, cmd_table=0xe0203a04,
aux_cmd_tablep=0xe022cbcc) at ../../ddb/db_command.c:337
#4 0xe0101502 in db_command_loop () at ../../ddb/db_command.c:462
#5 0xe0103c93 in db_trap (type=3, code=0) at ../../ddb/db_trap.c:75
#6 0xe01c48f1 in kdb_trap (type=3, code=0, regs=0xe0202d60)
at ../../i386/i386/db_interface.c:140
#7 0xe01cee84 in trap (frame={tf_es = 16, tf_ds = 16, tf_edi = 2,
tf_esi = 134, tf_ebp = -534762076, tf_isp = -534762104, tf_ebx = 6,
tf_edx = -535016767, tf_ecx = -1073490214, tf_eax = 38, tf_trapno = 3,
tf_err = 0, tf_eip = -535016711, tf_cs = 8, tf_eflags = 598,
tf_esp = -535016783, tf_ss = -534846881}) at ../../i386/i386/trap.c:403
#8 0xe01c4af9 in Debugger (msg=0xe01ee25f "manual escape to debugger")
at ../../i386/i386/db_interface.c:269
#9 0xe01eef7e in scgetc (flags=2) at ../../i386/isa/syscons.c:3001
#10 0xe01ea50f in scintr (unit=0) at ../../i386/isa/syscons.c:657
#11 0xe01d047b in getit () at ../../i386/isa/clock.c:353
#12 0xe01d0525 in DELAY (n=1000) at ../../i386/isa/clock.c:422
#13 0xe019de02 in sc_err1 (xs=0xf007f380) at ../../scsi/scsi_base.c:762
#14 0xe019da75 in scsi_scsi_cmd (sc_link=0xef49da00, scsi_cmd=0xe0202eb4,
cmdlen=10, data_addr=0xf5521000 "\204\027E\013\013s7?7", datalen=32768,
retries=4, timeout=10000, bp=0xf0f6dd00, flags=2049)
at ../../scsi/scsi_base.c:584
#15 0xe01a26ed in sdstart (unit=6, flags=1) at ../../scsi/sd.c:628
#16 0xe019d24e in free_xs (xs=0xf007f380, sc_link=0xef49da00, flags=1)
at ../../scsi/scsi_base.c:128
#17 0xe019d75a in scsi_done (xs=0xf007f380) at ../../scsi/scsi_base.c:449
#18 0xe01f9008 in ahc_done (ahc=0xefea3000, scb=0xefea4ec0)
at ../../i386/scsi/aic7xxx.c:1951
#19 0xe01fc7b1 in ahc_run_done_queue (ahc=0xefea3000)
at ../../i386/scsi/aic7xxx.c:3796
#20 0xe01fc77a in ahc_reset_channel (ahc=0xefea3000, channel=65 'A',
xs_error=3, initiate_reset=1) at ../../i386/scsi/aic7xxx.c:3782
#21 0xe01fae7b in ahc_timeout (arg=0xf0110380)
at ../../i386/scsi/aic7xxx.c:3031
#22 0xe010f21c in softclock () at ../../kern/kern_clock.c:717
(kgdb)
When scsi_scsi_cmd calls ahc_scsi_cmd, ahc_scsi_cmd detects that
ahc->in_reset is nonzero, and returns COMPLETE; with xs->error set to
XS_BUSY
scsi_scsi_cmd then calls sc_err1. sc_err1 performs a DELAY(1000),
before returning SCSIRET_DO_RETRY. This causes scsi_scsi_cmd to
go to the retry label, causing an infinite loop.
Due to this infinite loop being initiated from a timeout,
further timeouts are blocked, and ahc->in_reset is never cleared.
Perhaps free_xs should know when to NOT queue a new request onto the
device ?
- Tor Egge
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199704071553.RAA23471>