Panic on boot with today's CURRENT, ata related
Nate Lawson
nate at root.org
Fri Aug 6 15:31:16 PDT 2004
Radek Kozlowski wrote:
> On Fri, Aug 06, 2004 at 01:33:46PM -0700, Nate Lawson wrote:
>
>>I took a quick look at this ATA panic. The exact same one occurs for
>>Ceri. A quick dissassemble shows that the testb is the check for the
>>DMA flag at the very end of ata_generic_transaction(). The bug appears
>>to be that this may be a PIO request (since the DMA check is outside the
>>switch() statement). The fix is to make sure it's a DMA request before
>>dereferencing an element of the DMA struct. Try the attached patch.
>
>
> I applied your changes to ata-lowlevel.c revision 1.41 manually and they
> seem to solve the issue--my system now boots succesfully, thank you.
You're welcome. I committed the fix.
> I would also like to point out that since around the beggining of June
> the ad0 here no longer boots in UDMA100 mode but uses PIO4 instead
> (http://lists.freebsd.org/pipermail/freebsd-current/2004-June/029434.html).
>
> Trying to change the transfer mode to UDMA100 using atacontrol results
> in a panic. I don't know if this backtrace will be in any way useful but
> here it goes:
>
> Fatal trap 12: page fault while in kernel mode
> fault virtual address = 0x48
> fault code = supervisor read, page not present
> instruction pointer = 0x8:0xc0449391
> stack pointer = 0x10:0xd302dba0
> frame pointer = 0x10:0xd302dbd4
> code segment = base 0x0, limit 0xfffff, type 0x1b
> = DPL 0, pres 1, def32 1, gran 1
> processor eflags = interrupt enabled, resume, IOPL = 0
> current process = 4 (g_down)
>
> (kgdb) bt
> #0 doadump () at pcpu.h:159
> #1 0xc04427f5 in db_fncall (dummy1=0, dummy2=0, dummy3=3999, dummy4=0xd302d9ac " `q<C0>\f")
> at /usr/src/sys/ddb/db_command.c:531
> #2 0xc0442572 in db_command (last_cmdp=0xc0715724, cmd_table=0x0, aux_cmd_tablep=0xc06e2d90,
> aux_cmd_tablep_end=0xc06e2d94) at /usr/src/sys/ddb/db_command.c:349
> #3 0xc044267a in db_command_loop () at /usr/src/sys/ddb/db_command.c:455
> #4 0xc0444695 in db_trap (type=12, code=0) at /usr/src/sys/ddb/db_main.c:221
> #5 0xc052c057 in kdb_trap (type=0, code=0, tf=0xd302db60) at /usr/src/sys/kern/subr_kdb.c:401
> #6 0xc068e5c8 in trap_fatal (frame=0xd302db60, eva=0) at /usr/src/sys/i386/i386/trap.c:807
> #7 0xc068e2f3 in trap_pfault (frame=0xd302db60, usermode=0, eva=72) at /usr/src/sys/i386/i386/trap.c:730
> #8 0xc068de82 in trap (frame=
> {tf_fs = 24, tf_es = 16, tf_ds = 16, tf_edi = -1047235072, tf_esi = -1045272284, tf_ebp = -754787372, tf_isp = -754787444, tf_ebx = -1
> 047235072, tf_edx = 0, tf_ecx = 9167, tf_eax = -1047234904, tf_trapno = 12, tf_err = 0, tf_eip = -1069247599, tf_cs = 8, tf_eflags = 66050,
> tf_esp = -1047234904, tf_ss = -805982208}) at /usr/src/sys/i386/i386/trap.c:417
> #9 0xc0449391 in ata_generic_transaction (request=0xc1b26924) at /usr/src/sys/dev/ata/ata-lowlevel.c:144
> #10 0xc0448379 in ata_start (ch=0xc1947600) at /usr/src/sys/dev/ata/ata-queue.c:194
> #11 0xc0447f0c in ata_queue_request (request=0xc1b26924) at /usr/src/sys/dev/ata/ata-queue.c:91
> #12 0xc04595d8 in ad_start (atadev=0xc19476a8) at /usr/src/sys/dev/ata/ata-disk.c:310
> #13 0xc04481c8 in ata_start (ch=0xc1947600) at /usr/src/sys/dev/ata/ata-queue.c:168
> #14 0xc045922e in adstrategy (bp=0xc1e5f738) at /usr/src/sys/dev/ata/ata-disk.c:229
> #15 0xc04cf8f6 in g_disk_start (bp=0xc1b29e70) at /usr/src/sys/geom/geom_disk.c:277
> #16 0xc04d17c0 in g_io_schedule_down (tp=0xc188f000) at /usr/src/sys/geom/geom_io.c:365
> #17 0xc04d1b1e in g_down_procbody () at /usr/src/sys/geom/geom_kern.c:113
> #18 0xc04f4ed0 in fork_exit (callout=0xc04d1b00 <g_down_procbody>, arg=0x0, frame=0x0)
> at /usr/src/sys/kern/kern_fork.c:819
It looks like the DMA object for the channel is not being initialized.
However, that is in another path (this backtrace is just a symptom
triggered by the first DMA access to the drive). Someone who knows more
about the control path for going from PIO -> DMA mode will have to look
into this.
-Nate
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