Message-Id: <20080507163155.1217515f.akpm@linux-foundation.org>
Date:	Wed, 7 May 2008 16:31:55 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	"Yinghai Lu" <yhlu.kernel@...il.com>
Cc:	yhlu.kernel@...il.com, James.Bottomley@...senpartnership.com,
	linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
	sathya.prakash@....com, Eric.Moore@....com, ebiederm@...ssion.com
Subject: Re: [PATCH] mptsas: add mptsas_shutdown to call pci_disable_msi

On Tue, 22 Apr 2008 20:12:08 -0700
"Yinghai Lu" <yhlu.kernel@...il.com> wrote:

> On Tue, Apr 22, 2008 at 7:47 PM, Yinghai Lu <yhlu.kernel.send@...il.com> wrote:
> >
> >
> >  this change
> >
> >  | commit 23a274c8a5adafc74a66f16988776fc7dd6f6e51
> >  | Author: Prakash, Sathya <sathya.prakash@....com>
> >  | Date:   Fri Mar 7 15:53:21 2008 +0530
> >  |
> >  |     [SCSI] mpt fusion: Enable MSI by default for SAS controllers
> >  |
> >  |     This patch modifies the driver to enable MSI by default for all SAS chips.
> >  |
> >  cause kexec RHEL 5.1 kernel fail.
> >
> >  root casue: the rhel 5.1 kernel still use INTx emulation.
> >  and mptscsih_shutdown doesn't call pci_disable_msi to reenable INTx on kexec path
> >
> >  so try to call mptsas_remove in mptsas_shutdown.
> >  then pci_disable_msi will be called via mptsas_remove==>mptscih_remove==>
> >  mpt_detach.
> >
> >  Signed-off-by: Yinghai Lu <yhlu.kernel@...il.com>
> >  CC: Prakash, Sathya <sathya.prakash@....com>
> >  CC: "Moore, Eric" <Eric.Moore@....com>
> >
> >  Index: linux-2.6/drivers/message/fusion/mptsas.c
> >  ===================================================================
> >  --- linux-2.6.orig/drivers/message/fusion/mptsas.c
> >  +++ linux-2.6/drivers/message/fusion/mptsas.c
> >  @@ -3327,6 +3327,11 @@ static void __devexit mptsas_remove(stru
> >         mptscsih_remove(pdev);
> >   }
> >
> >  +static void mptsas_shutdown(struct pci_dev *pdev)
> >  +{
> >  +       mptsas_remove(pdev);
> >  +}
> >  +
> >   static struct pci_device_id mptsas_pci_table[] = {
> >         { PCI_VENDOR_ID_LSI_LOGIC, MPI_MANUFACTPAGE_DEVID_SAS1064,
> >                 PCI_ANY_ID, PCI_ANY_ID },
> >  @@ -3348,7 +3353,7 @@ static struct pci_driver mptsas_driver =
> >         .id_table       = mptsas_pci_table,
> >         .probe          = mptsas_probe,
> >         .remove         = __devexit_p(mptsas_remove),
> >  -       .shutdown       = mptscsih_shutdown,
> >  +       .shutdown       = mptsas_shutdown,
> >   #ifdef CONFIG_PM
> >         .suspend        = mptscsih_suspend,
> >         .resume         = mptscsih_resume,
> >  --
> 
> fail on one system with big sas expander...
> 
> LBSuse:~ # mkdir /xx
> LBSuse:~ # mount /dev/sdl1 /xx
> LBSuse:~ # cd /xx
> LBSuse:/xx # sh kk_rh_5.1
> LBSuse:/xx # ./kexec -e
> BUG: unable to handle kernel NULL pointer dereference at 0000000000000028
> IP: [<ffffffff80337af4>] sysfs_find_dirent+0x1f/0x5f
> PGD 41f137067 PUD 424482067 PMD 0
> Oops: 0000 [1] SMP
> CPU 7
> Modules linked in:
> Pid: 7534, comm: kexec Not tainted

I don't understand your email.

Are you saying that this oops is the thing which your patch fixes?

Or are you saying that this oops occurs even after your patch is applied? 
That we have a second regression?

> 2.6.25-sched-devel.git-x86-latest.git-03823-g1508ed0-dirty #135
> RIP: 0010:[<ffffffff80337af4>]  [<ffffffff80337af4>] sysfs_find_dirent+0x1f/0x5f
> RSP: 0018:ffff8104238f7708  EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffffffff80cd36a5 RCX: 000000008c0f362e
> RDX: ffffffff80e20ab0 RSI: ffffffff80cd36a5 RDI: 0000000000000000
> RBP: ffff8104238f7728 R08: 0000000000000000 R09: 000000008c0f362e
> R10: ffff8104238f77f8 R11: 000000008c0f362e R12: 0000000000000000
> R13: ffff810223190358 R14: 0000000000000000 R15: 0000000000000000
> FS:  00007fde8859d6f0(0000) GS:ffff810427039f00(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> CR2: 0000000000000028 CR3: 00000004238b8000 CR4: 00000000000006e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process kexec (pid: 7534, threadinfo ffff8104238f6000, task ffff8104238e0000)
> Stack:  0000000000000000 000000008c0f362e ffffffff80cd36a5 0000000000000000
>  ffff8104238f7758 ffffffff80337b70 000000008c0f362e 000000008c0f362e
>  ffff810223190268 ffffffff80e1fb20 ffff8104238f7798 ffffffff8033966e
> Call Trace:
>  [<ffffffff80337b70>] sysfs_get_dirent+0x3c/0x72
>  [<ffffffff8033966e>] sysfs_remove_group+0x38/0xb4
>  [<ffffffff80633007>] dpm_sysfs_remove+0x2f/0x45
>  [<ffffffff806336d3>] device_pm_remove+0x34/0x85
>  [<ffffffff8062b283>] device_del+0x30/0x1b0
>  [<ffffffff8062b428>] device_unregister+0x25/0x48
>  [<ffffffff80639e73>] enclosure_unregister+0x85/0xcb
>  [<ffffffff807dad42>] ses_intf_remove+0x8b/0xa8
>  [<ffffffff8062b2fb>] device_del+0xa8/0x1b0
>  [<ffffffff8062b428>] device_unregister+0x25/0x48
>  [<ffffffff80700bb4>] __scsi_remove_device+0x4c/0xaf
>  [<ffffffff80700c50>] scsi_remove_device+0x39/0x5c
>  [<ffffffff80700d15>] __scsi_remove_target+0xa2/0xf6
>  [<ffffffff80700de0>] ? __remove_child+0x0/0x4f
>  [<ffffffff80700e12>] __remove_child+0x32/0x4f
>  [<ffffffff8062ab27>] ? next_device+0x21/0x45
>  [<ffffffff8062ac23>] device_for_each_child+0x40/0x84
>  [<ffffffff80713d8e>] ? do_sas_phy_delete+0x0/0x66
>  [<ffffffff80700dbc>] scsi_remove_target+0x53/0x77
>  [<ffffffff807134b0>] sas_rphy_remove+0x42/0x81
>  [<ffffffff80713514>] sas_rphy_delete+0x25/0x48
>  [<ffffffff80713570>] sas_port_delete+0x39/0x147
>  [<ffffffff802259e0>] ? mcount_call+0x5/0x35
>  [<ffffffff80713d8e>] ? do_sas_phy_delete+0x0/0x66
>  [<ffffffff80713dc2>] do_sas_phy_delete+0x34/0x66
>  [<ffffffff8062ac23>] device_for_each_child+0x40/0x84
>  [<ffffffff80713d8e>] ? do_sas_phy_delete+0x0/0x66
>  [<ffffffff8071343f>] sas_remove_children+0x2e/0x5d
>  [<ffffffff807134b7>] sas_rphy_remove+0x49/0x81
>  [<ffffffff80713514>] sas_rphy_delete+0x25/0x48
>  [<ffffffff80713570>] sas_port_delete+0x39/0x147
>  [<ffffffff802259e0>] ? mcount_call+0x5/0x35
>  [<ffffffff80713d8e>] ? do_sas_phy_delete+0x0/0x66
>  [<ffffffff80713dc2>] do_sas_phy_delete+0x34/0x66
>  [<ffffffff8062ac23>] device_for_each_child+0x40/0x84
>  [<ffffffff8071343f>] sas_remove_children+0x2e/0x5d
>  [<ffffffff807136a6>] sas_remove_host+0x28/0x3e
>  [<ffffffff80ab22ab>] mptsas_remove+0x46/0x107
>  [<ffffffff802259e0>] ? mcount_call+0x5/0x35
>  [<ffffffff8080ef6d>] mptsas_shutdown+0x21/0x37
>  [<ffffffff805a6815>] pci_device_shutdown+0x37/0x4d
>  [<ffffffff8062a2ad>] device_shutdown+0x64/0xa0
>  [<ffffffff8027e57f>] ? blocking_notifier_call_chain+0x27/0x3d
>  [<ffffffff8027131e>] kernel_restart_prepare+0x3f/0x5a
>  [<ffffffff802716f7>] sys_reboot+0x172/0x1cb
>  [<ffffffff802e2ac0>] ? __fput+0x158/0x17b
>  [<ffffffff802efc4e>] ? vfs_ioctl+0x3e/0xa2
>  [<ffffffff802e2ef0>] ? fput+0x2c/0x42
>  [<ffffffff802df2d2>] ? filp_close+0x78/0x9a
>  [<ffffffff802df0b4>] ? __put_unused_fd+0x33/0x60
>  [<ffffffff802e0bed>] ? sys_close+0x8c/0xdf
>  [<ffffffff80225b9b>] system_call_after_swapgs+0x7b/0x80
> 
> 
> Code: e8 37 85 f2 ff 48 83 c4 18 5b c9 c3 55 48 89 e5 41 54 53 48 83
> ec 10 66 66 90 66 90 65 48 8b 04 25 28 00 00 00 48 89 45 e8 31 c0 <48>
> 8b 5f 28 49 89 f4 eb 14 48 8b 7b 18 4c 89 e6 e8 25 e8 25 00
> RIP  [<ffffffff80337af4>] sysfs_find_dirent+0x1f/0x5f
>  RSP <ffff8104238f7708>
> CR2: 0000000000000028
> ---[ end trace 4ca22418d73866ec ]---
> 
> may need create mptsas that only call pci_disable_msi
> 

It would be strange for an interrupt-disabling problem to cause sysfs to go
oops?

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