[Bug 95101] scsi/mpt2sas: setpci reset results in kernel oops

[Bug 95101] scsi/mpt2sas: setpci reset results in kernel oops

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=95101

Nagarajkumar N <nagarajkumar.narayanan@seagate.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |linux-scsi@vger.kernel.org,
                   |                            |nagarajkumar.narayanan@seag
                   |                            |ate.com

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[Bug 95101] scsi/mpt2sas: setpci reset results in kernel oops

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=95101

Joe Lawrence <joe.lawrence@stratus.com> changed:

           What    |Removed                     |Added
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                 CC|                            |joe.lawrence@stratus.com

--- Comment #1 from Joe Lawrence <joe.lawrence@stratus.com> ---
>From the /var/log/messages attachment:

Mar 16 01:13:10 RHEL63 kernel: mpt2sas1: _base_fault_reset_work: Running
mpt2sas_dead_ioc thread success !!!!
...
Mar 16 01:13:20 RHEL63 kernel: mpt2sas1: _scsih_ir_shutdown: timeout
Mar 16 01:13:20 RHEL63 kernel: mpt2sas1: removing handle(0x0024),
wwid(0x0c4e8a1c03a9b742)

indicates that _scsih_remove was called when the driver's watchdog detected
that the device was misbehaving.  Driver device removal invokes:

mpt2sas_base_detach
  mpt2sas_base_free_resources
    iounmap(ioc->chip)

setting the stage for the crash:

Mar 16 01:13:37 RHEL63 kernel: BUG: unable to handle kernel paging request at
ffffc900171e0000                             
Mar 16 01:13:37 RHEL63 kernel: IP: [<ffffffffa00502e0>]
mpt2sas_base_get_iocstate+0x10/0x30 [mpt2sas]
...
Mar 16 01:13:37 RHEL63 kernel: RAX: ffffc900171e0000 RBX: ffff88105a0aa788 RCX:
0000000000004fdc

where mpt2sas_base_get_iocstate was probably calling
readl(&ioc->chip->Doorbell)

So it would seem that the mpt2sas ioctl code (step 5, I think) isn't
synchronized against device removal.

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[Bug 95101] scsi/mpt2sas: setpci reset results in kernel oops

[bugzilla-daemon]

https://bugzilla.kernel.org/show_bug.cgi?id=95101

--- Comment #2 from Nagarajkumar N <nagarajkumar.narayanan@seagate.com> ---
Created attachment 172971
  --> https://bugzilla.kernel.org/attachment.cgi?id=172971&action=edit
mpt2sas pci resource removal synchronization patch

The attached patch need to applied on latest linux main git branch on
scsi/mpt2sas
The patch provides syncrhonization between cli, brm status show and pci
resource removal path through mutex lock and spinlock protection on linked list
of controllers (multiple warpdrive cards are used) on controller resource
removal and addition

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