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Groups > linux.kernel > #1184287 > unrolled thread
| Started by | Yinghai Lu <yinghai@kernel.org> |
|---|---|
| First post | 2015-07-15 07:40 +0200 |
| Last post | 2015-07-15 17:00 +0200 |
| Articles | 4 — 4 participants |
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Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected Yinghai Lu <yinghai@kernel.org> - 2015-07-15 07:40 +0200
Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected Sreekanth Reddy <sreekanth.reddy@avagotech.com> - 2015-07-15 08:40 +0200
Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected Timothy Pearson <tpearson@raptorengineeringinc.com> - 2015-07-15 16:10 +0200
Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected Bjorn Helgaas <bhelgaas@google.com> - 2015-07-15 17:00 +0200
| From | Yinghai Lu <yinghai@kernel.org> |
|---|---|
| Date | 2015-07-15 07:40 +0200 |
| Subject | Re: [PATCH v3] [SCSI] mpt2sas, mpt3sas: Abort initialization if no memory I/O resources detected |
| Message-ID | <pMnAd-6xs-1@gated-at.bofh.it> |
On Tue, Jul 14, 2015 at 9:49 PM, Sreekanth Reddy <sreekanth.reddy@avagotech.com> wrote: > Driver crashes if the BIOS do not set up at least one > memory I/O resource. This failure can happen if the device is too > slow to respond during POST and is missed by the BIOS, but Linux > then detects the device later in the boot process. But pci subsystem should assign resources to those unassigned BAR. Do you mean even kernel can not assign resource to them? or it takes so long for mpt FW to get ready? Thanks Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Sreekanth Reddy <sreekanth.reddy@avagotech.com> |
|---|---|
| Date | 2015-07-15 08:40 +0200 |
| Message-ID | <pMowj-7Sm-45@gated-at.bofh.it> |
| In reply to | #1184287 |
On Tue, Jul 14, 2015 at 10:36:58PM -0700, Yinghai Lu wrote: > On Tue, Jul 14, 2015 at 9:49 PM, Sreekanth Reddy > <sreekanth.reddy@avagotech.com> wrote: > > Driver crashes if the BIOS do not set up at least one > > memory I/O resource. This failure can happen if the device is too > > slow to respond during POST and is missed by the BIOS, but Linux > > then detects the device later in the boot process. > > But pci subsystem should assign resources to those unassigned BAR. > > Do you mean even kernel can not assign resource to them? or it takes so long for > mpt FW to get ready? This is not an issue from mpt FW. I have just kept the same description provide by Timothy in his initial patch. But I observe that their may be chance of getting "unable to handle kernel NULL pointer dereference" kernel panic if no Memory Resource available in the PCI subsystem. So agreed to the Timothy proposal of aborting the driver initialization if it doesn't detect any Memory resource instead of whole system get into panic state. > > Thanks > > Yinghai -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Timothy Pearson <tpearson@raptorengineeringinc.com> |
|---|---|
| Date | 2015-07-15 16:10 +0200 |
| Message-ID | <pMvxM-1jg-19@gated-at.bofh.it> |
| In reply to | #1184327 |
On 07/15/2015 01:24 AM, Sreekanth Reddy wrote: > On Tue, Jul 14, 2015 at 10:36:58PM -0700, Yinghai Lu wrote: >> On Tue, Jul 14, 2015 at 9:49 PM, Sreekanth Reddy >> <sreekanth.reddy@avagotech.com> wrote: >>> Driver crashes if the BIOS do not set up at least one >>> memory I/O resource. This failure can happen if the device is too >>> slow to respond during POST and is missed by the BIOS, but Linux >>> then detects the device later in the boot process. >> >> But pci subsystem should assign resources to those unassigned BAR. >> >> Do you mean even kernel can not assign resource to them? or it takes so long for >> mpt FW to get ready? > > This is not an issue from mpt FW. > > I have just kept the same description provide by Timothy in his > initial patch. > > But I observe that their may be chance of getting "unable to handle > kernel NULL pointer dereference" kernel panic if no Memory Resource > available in the PCI subsystem. So agreed to the Timothy proposal of > aborting the driver initialization if it doesn't detect any Memory > resource instead of whole system get into panic state. > >> >> Thanks >> >> Yinghai On some systems Linux is unable / unwilling to assign a BAR if the BIOS does not assign one at startup. I didn't look into the Linux allocator side of things in much detail, but it is quite possible that Linux is unaware the device only has partial resources assigned. -- Timothy Pearson Raptor Engineering +1 (415) 727-8645 http://www.raptorengineeringinc.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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| From | Bjorn Helgaas <bhelgaas@google.com> |
|---|---|
| Date | 2015-07-15 17:00 +0200 |
| Message-ID | <pMwka-2xg-19@gated-at.bofh.it> |
| In reply to | #1184826 |
On Wed, Jul 15, 2015 at 08:52:13AM -0500, Timothy Pearson wrote: > On 07/15/2015 01:24 AM, Sreekanth Reddy wrote: > > On Tue, Jul 14, 2015 at 10:36:58PM -0700, Yinghai Lu wrote: > >> On Tue, Jul 14, 2015 at 9:49 PM, Sreekanth Reddy > >> <sreekanth.reddy@avagotech.com> wrote: > >>> Driver crashes if the BIOS do not set up at least one > >>> memory I/O resource. This failure can happen if the device is too > >>> slow to respond during POST and is missed by the BIOS, but Linux > >>> then detects the device later in the boot process. > >> > >> But pci subsystem should assign resources to those unassigned BAR. > >> > >> Do you mean even kernel can not assign resource to them? or it takes so long for > >> mpt FW to get ready? > > > > This is not an issue from mpt FW. > > > > I have just kept the same description provide by Timothy in his > > initial patch. > > > > But I observe that their may be chance of getting "unable to handle > > kernel NULL pointer dereference" kernel panic if no Memory Resource > > available in the PCI subsystem. So agreed to the Timothy proposal of > > aborting the driver initialization if it doesn't detect any Memory > > resource instead of whole system get into panic state. > > On some systems Linux is unable / unwilling to assign a BAR if the BIOS > does not assign one at startup. I didn't look into the Linux allocator > side of things in much detail, but it is quite possible that Linux is > unaware the device only has partial resources assigned. There might be a Linux PCI core bug if we don't assign a BAR, although resource assignment can always fail, even in the absence of bugs. But there is definitely a driver bug if it uses ioc->chip when it hasn't been initialized. That's what this patch seems to fix. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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