[Bug 208605] New: AACRAID frequent hos bus reset with intensive IO on large arrays

[Bug 208605] New: AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

            Bug ID: 208605
           Summary: AACRAID frequent hos bus reset with intensive IO on
                    large arrays
           Product: SCSI Drivers
           Version: 2.5
    Kernel Version: 4.14 - 5.7.8
          Hardware: x86-64
                OS: Linux
              Tree: Mainline
            Status: NEW
          Severity: normal
          Priority: P1
         Component: AACRAID
          Assignee: scsi_drivers-aacraid@kernel-bugs.osdl.org
          Reporter: janpieter.sollie@edpnet.be
        Regression: No

Created attachment 290345
  --> https://bugzilla.kernel.org/attachment.cgi?id=290345&action=edit
quick and dirty patch to fix the issue

On a large array (>15 drives), it is impossible to backup the storage to a SAS
tape without the driver detecting a lockup, and causing a bus reset.
This seems to be a false detection, as the host controller actually is not
locking up anything.  It's just a bit delayed.
This issue seems to go back to 4.14.

I reverted some cleanup stuff introduced in 4.14, and the driver is working
correctly.

I attached a patch for it, but this is just to show where the bug may be, it is
not ready for production (though it works, but this may be for 7 series only). 
I also have no idea what exactly causes this issue

Bug observed on a series 7 controller with a 12-drive RAID6 array.

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

--- Comment #1 from Janpieter Sollie (janpieter.sollie@edpnet.be) ---
Sorry, this patch seems to be a false positive ... the error still occurs:
scsi_eh_handler still appears, though a little later

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

Andrey Jr. Melnikov (temnota.am@gmail.com) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |temnota.am@gmail.com

--- Comment #2 from Andrey Jr. Melnikov (temnota.am@gmail.com) ---
check this https://patchwork.kernel.org/patch/11038347/

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

--- Comment #3 from Janpieter Sollie (janpieter.sollie@edpnet.be) ---
I saw that, the modifications are included in this patch (but for 7 series
instead of 6), but they do not seem to work.  There must be another issue.
I know that the controller works fine when issuing commands like create / erase
/ repair etc ... but during large IO, it fails.  So there must be some sync
issue between the scsi subsystem (or the aacraid driver) and the adapter.

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

--- Comment #4 from Janpieter Sollie (janpieter.sollie@edpnet.be) ---
Created attachment 290373
  --> https://bugzilla.kernel.org/attachment.cgi?id=290373&action=edit
modification to make Microsemi driver work with 5.7 kernel

I know this is bad practice, but at least it produces some results:
I tried the proprietary Microsemi driver (58012).  Of course it does not work
with recent kernels, but after modifying the code a bit, I made "something"
that works.
Patch in attachment.  Any idea why this one works but the open source variant
does not? When I take a look at the amount of abandoned / junk in the code of
Microsemi after modifying, I'd expect the opposite.

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

--- Comment #5 from Janpieter Sollie (janpieter.sollie@edpnet.be) ---
I think I found a solution:
When I force sync mode, the driver handles everything perfectly.  Off course
this has a performance impact, so if anyone could help me debug this driver in
async mode, it would be very much appreciated ...

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[Bug 208605] AACRAID frequent hos bus reset with intensive IO on large arrays

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=208605

Janpieter Sollie (janpieter.sollie@edpnet.be) changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |INVALID

--- Comment #6 from Janpieter Sollie (janpieter.sollie@edpnet.be) ---
the previous setting was no solution.  The functionality of the driver is
largely reduced. aacraid cache=3 & arcconf setcache ld 1 coff & echo "write
through" > /sys/block/sdc/queue/write_cache fixed the issue.  This is most
probably hardware related.  No linux bug

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