Re: 2.6.23-mm1

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Torsten Kaiser wrote:
On 10/13/07, Jeff Garzik <[email protected]> wrote:
Torsten Kaiser wrote:
On 10/12/07, Andrew Morton <[email protected]> wrote:
On Fri, 12 Oct 2007 10:31:42 +0200 "Torsten Kaiser" <[email protected]> wrote:
Oct 12 10:23:03 treogen smartd[6091]: Device: /dev/sdc, not found in
smartd database.
hm.

Oct 12 10:23:03 treogen [  105.990000] WARNING: at
drivers/ata/libata-core.c:5752 ata_qc_issue()
Let's cc linux-ide.

Oct 12 10:23:03 treogen [  105.990000]
Oct 12 10:23:03 treogen [  105.990000] Call Trace:
Oct 12 10:23:03 treogen [  105.990000]  [<ffffffff804442ef>]
ata_qc_issue+0x47f/0x540
Oct 12 10:23:03 treogen [  105.990000]  [<ffffffff80432e60>] scsi_done+0x0/0x20
Oct 12 10:23:03 treogen [  105.990000]  [<ffffffff80449c80>]
ata_scsi_flush_xlat+0x0/0x30
Oct 13 07:46:48 treogen [   99.850000]
Oct 13 07:46:48 treogen [   99.850000] ata3: EH in SWNCQ
mode,QC:qc_active 0x3 sactive 0x1
Oct 13 07:46:48 treogen [   99.850000] ata3: SWNCQ:qc_active 0x1
defer_bits 0x0 last_issue_tag 0x0
The WARNING indicates that there is a SWNCQ bug in sata_nv.  Given that
the problem appears when SYNCHRONIZE CACHE is being issued, I would

I can't follow you on SYNCHRONIZE CACHE.
The only command written to the syslog in the errors where
0x60==ATA_CMD_FPDMA_READ and 0xB0 (which is not in
include/linux/ata.h, but ATA-6 says that this is SMART related. That
makes sense, as smartd is failing).

In the traceback you have "ata_scsi_flush_xlat", which is the function that translates a SCSI sync-cache command into an ATA flush-cache command.

The "WARNING: at drivers/ata/libata-core.c:5752 ata_qc_issue()" also guides us to the code comment

        /* Make sure only one non-NCQ command is outstanding.  The
         * check is skipped for old EH because it reuses active qc to
         * request ATAPI sense.
         */

which is a check related to NCQ->off and off->NCQ edge cases.

So those are the two bits of information I found interesting.


guess that sata_nv is not properly handling non-queued commands.

But that still seems correct, as I would not expect that SMART
commands get queued. (Thats just a guess, as I did not try to find the
code that does this distinction)

This is a patch from libata-dev.git#nv-swncq (via #ALL).

Comparing sata_nv.c from 2.6.23-rc8-mm1 and 2.6.23-mm1 I see two
changes, that look suspicious:

http://git.kernel.org/?p=linux/kernel/git/jgarzik/libata-dev.git;a=commitdiff;h=31cc23b34913bc173680bdc87af79e551bf8cc0d

The comment says: "ahci and sata_sil24 are converted to use ata_std_qc_defer()."
But the patch also adds ".qc_defer = ata_std_qc_defer," to sata_nv.c

The second change is the removal of the 'lock' spinlock from sata_nv.c
that was used in nv_swncq_qc_issue and nv_swncq_host_interrupt.

Should I try to revert one or both of these changes?

If you are git-capable, IMO the next steps in problem elimination should be

* download latest linux-2.6.git (currently 752097cec53eea111d087c545179b421e2bde98a)
* build and test linux-2.6.git, to establish a new baseline
* download latest libata-dev.git#nv-swncq (currently 3cb664c2d319a4fde5028c3c5dab6221fe70bd2d)
* build and test, with sata_nv module option swncq=0
* build and test, with sata_nv module option swncq=1

That will get -mm out of the picture, use the same baseline kernel for all three tests (nv-swncq is based off of 752097cec53eea111d087c545179b421e2bde98a) and narrow things down to the precise changes that went upstream (or are on the 'nv-swncq' branch, waiting to go upstream).

My gut feeling is that there is a lingering bug in sata_nv SWNCQ somewhere.

	Jeff



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux