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From: Keith Busch <keith.busch@intel.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Sinan Kaya <okaya@kernel.org>, Thomas Tai <thomas.tai@oracle.com>,
	poza@codeaurora.org, Lukas Wunner <lukas@wunner.de>,
	Christoph Hellwig <hch@lst.de>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 00/12] error handling and pciehp maintenance
Date: Tue, 6 Nov 2018 09:47:52 -0700	[thread overview]
Message-ID: <20181106164751.GA6217@localhost.localdomain> (raw)
In-Reply-To: <20181106163400.GA21193@e107981-ln.cambridge.arm.com>

On Tue, Nov 06, 2018 at 04:34:08PM +0000, Lorenzo Pieralisi wrote:
> The question is whether we really need to dynamically patch the kernel
> with ftrace to achieve what that patch does.
> 
> Furthermore, it would also be good to report what bugs we are actually
> fixing, from what you are writing falling back to the current method if
> !DYNAMIC_FTRACE_WITH_REGS is broken in many ways and I would start with
> fixing the current behaviour with something that does not depend on arch
> features that may not even be implemented.

There are two problems with the current method:

  1. It may dereference pci_dev after it was freed
  2. The pci_dev's children inherit its fake pci_bus's ops on
     enumeration

Both result in kernel panic.

The dynamic kernel patch just seemed like a cool way to inject errors
without messing with the driver's structures. But if there's a more
elegant way to do it, I'm all for it.

  reply	other threads:[~2018-11-06 16:50 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-18 23:58 [PATCH 00/12] error handling and pciehp maintenance Keith Busch
2018-09-18 23:58 ` [PATCH 01/12] PCI: Set PCI bus accessors to noinline Keith Busch
2018-09-18 23:58 ` [PATCH 02/12] PCI/AER: Covertly inject errors Keith Busch
2018-09-18 23:58 ` [PATCH 03/12] PCI/AER: Reuse existing service device lookup Keith Busch
2018-09-18 23:58 ` [PATCH 04/12] PCI/AER: Abstract AER interrupt handling Keith Busch
2018-09-18 23:58 ` [PATCH 05/12] PCI/AER: Remove dead code Keith Busch
2018-09-18 23:58 ` [PATCH 06/12] PCI/AER: Remove error source from aer struct Keith Busch
2018-09-18 23:58 ` [PATCH 07/12] PCI/AER: Use kfifo for tracking events Keith Busch
2018-09-18 23:58 ` [PATCH 08/12] PCI/AER: Use kfifo helper inserting locked elements Keith Busch
2018-09-18 23:58 ` [PATCH 09/12] PCI/AER: Don't read upstream ports below fatal errors Keith Busch
2018-09-18 23:58 ` [PATCH 10/12] PCI/AER: Use threaded IRQ for bottom half Keith Busch
2018-09-18 23:58 ` [PATCH 11/12] PCI/AER: Use managed resource allocations Keith Busch
2018-09-19 16:29   ` Sinan Kaya
2018-09-19 17:25     ` Keith Busch
2018-09-19 17:36       ` Sinan Kaya
2018-09-25  1:13   ` Benjamin Herrenschmidt
2018-09-25 14:17     ` Keith Busch
2018-09-18 23:58 ` [PATCH 12/12] PCI/pciehp: Use device managed allocations Keith Busch
2018-09-19 15:11   ` Sinan Kaya
2018-09-19 16:17     ` Keith Busch
2018-09-22 18:10   ` Lukas Wunner
2018-09-24 23:43     ` Bjorn Helgaas
2018-09-25  7:13       ` Lukas Wunner
2018-10-04 21:40 ` [PATCH 00/12] error handling and pciehp maintenance Bjorn Helgaas
2018-10-04 22:11   ` Keith Busch
2018-10-05 17:31     ` Bjorn Helgaas
2018-10-08 16:18       ` Keith Busch
2018-10-08 17:23         ` Bjorn Helgaas
2018-11-06 16:34         ` Lorenzo Pieralisi
2018-11-06 16:47           ` Keith Busch [this message]
2018-11-06 17:21             ` Lorenzo Pieralisi
2018-11-06 17:26               ` Keith Busch
2018-10-09 16:03       ` Will Deacon

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