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From: Evgeny Baskakov <ebaskakov@nvidia.com>
To: Jerome Glisse <jglisse@redhat.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	John Hubbard <jhubbard@nvidia.com>,
	David Nellans <dnellans@nvidia.com>,
	Mark Hairgrove <mhairgrove@nvidia.com>,
	Sherry Cheung <SCheung@nvidia.com>,
	Subhash Gutti <sgutti@nvidia.com>
Subject: Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4
Date: Mon, 10 Jul 2017 15:59:37 -0700	[thread overview]
Message-ID: <f04a007d-fc34-fe3a-d366-1363248a609f@nvidia.com> (raw)
In-Reply-To: <20170701005749.GA7232@redhat.com>

[-- Attachment #1: Type: text/plain, Size: 1813 bytes --]

On 6/30/17 5:57 PM, Jerome Glisse wrote:
...

Hi Jerome,

I am seeing a strange crash in our code that uses the hmm_device_new() 
helper. After the driver is repeatedly loaded/unloaded, hmm_device_new() 
suddenly returns NULL.

I have reproduced this with the dummy driver from the hmm-next branch:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000208

(gdb) bt
#0  hmm_devmem_add (ops=0xffffffffa003a140, device=0x0 
<irq_stack_union>, size=0x4000000) at mm/hmm.c:997
#1  0xffffffffa0038236 in dmirror_probe (pdev=<optimized out>) at 
drivers/char/hmm_dmirror.c:1106
#2  0xffffffff815acfcb in platform_drv_probe (_dev=0xffff88081368ca78) 
at drivers/base/platform.c:578
#3  0xffffffff815ab0a4 in really_probe (drv=<optimized out>, 
dev=<optimized out>) at drivers/base/dd.c:385
#4  driver_probe_device (drv=0xffffffffa003b028, dev=0xffff88081368ca78) 
at drivers/base/dd.c:529
#5  0xffffffff815ab1d4 in __driver_attach (dev=0xffff88081368ca78, 
data=0xffffffffa003b028) at drivers/base/dd.c:763
#6  0xffffffff815a911d in bus_for_each_dev (bus=<optimized out>, 
start=<optimized out>, data=0x4000000, fn=0x18 <irq_stack_union+24>) at 
drivers/base/bus.c:313
#7  0xffffffff815aa98e in driver_attach (drv=<optimized out>) at 
drivers/base/dd.c:782
#8  0xffffffff815aa585 in bus_add_driver (drv=0xffffffffa003b028) at 
drivers/base/bus.c:669
#9  0xffffffff815abc10 in driver_register (drv=0xffffffffa003b028) at 
drivers/base/driver.c:168
#10 0xffffffff815acf46 in __platform_driver_register (drv=<optimized 
out>, owner=<optimized out>) at drivers/base/platform.c:636


Can you please look into this?

Here's a command to reproduce, using the kload.sh script (taken from a 
sanity suite you provided earlier, attached):

$ while true; do sudo ./kload.sh; done

Thanks!

Evgeny Baskakov
NVIDIA

[-- Attachment #2: kload.sh --]
[-- Type: application/x-sh, Size: 397 bytes --]

  parent reply	other threads:[~2017-07-10 22:59 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-22 16:51 [HMM 00/15] HMM (Heterogeneous Memory Management) v22 Jérôme Glisse
2017-05-22 16:51 ` [HMM 01/15] hmm: heterogeneous memory management documentation Jérôme Glisse
2017-05-22 16:51 ` [HMM 02/15] mm/hmm: heterogeneous memory management (HMM for short) v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 03/15] mm/hmm/mirror: mirror process address space on device with HMM helpers v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 04/15] mm/hmm/mirror: helper to snapshot CPU page table v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 05/15] mm/hmm/mirror: device page fault handler Jérôme Glisse
2017-05-22 16:51 ` [HMM 06/15] mm/memory_hotplug: introduce add_pages Jérôme Glisse
2017-05-22 16:51 ` [HMM 07/15] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v2 Jérôme Glisse
2017-05-22 21:17   ` Dan Williams
2017-05-23 21:36     ` [HMM 07/18] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v3 Jérôme Glisse
2017-05-23  8:36   ` [HMM 07/15] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v2 kbuild test robot
2017-05-22 16:51 ` [HMM 08/15] mm/ZONE_DEVICE: special case put_page() for device private pages Jérôme Glisse
2017-05-22 19:29   ` Dan Williams
2017-05-22 20:14     ` Jerome Glisse
2017-05-22 20:19       ` Dan Williams
2017-05-22 21:14         ` Jerome Glisse
2017-05-22 20:22       ` Hugh Dickins
2017-05-22 21:17         ` Jerome Glisse
2017-05-23  9:34   ` kbuild test robot
2017-05-23 13:23   ` Kirill A. Shutemov
2017-05-23 21:37     ` [HMM 08/18] mm/ZONE_DEVICE: special case put_page() for device private pages v2 Jérôme Glisse
2017-05-22 16:52 ` [HMM 09/15] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE v4 Jérôme Glisse
2017-05-23 21:37   ` [HMM 09/18] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE v5 Jérôme Glisse
2017-05-22 16:52 ` [HMM 10/15] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v3 Jérôme Glisse
2017-05-22 16:52 ` [HMM 11/15] mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY Jérôme Glisse
2017-05-22 16:52 ` [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4 Jérôme Glisse
2017-05-23 18:07   ` Reza Arbab
2017-06-27  0:07   ` Evgeny Baskakov
2017-06-30 23:19     ` Evgeny Baskakov
2017-07-01  0:57       ` Jerome Glisse
2017-07-01  2:06         ` Evgeny Baskakov
2017-07-10 22:59         ` Evgeny Baskakov [this message]
2017-07-10 23:43           ` Jerome Glisse
2017-07-11  0:17             ` Evgeny Baskakov
2017-07-11  0:54               ` Jerome Glisse
2017-07-20 21:05                 ` Evgeny Baskakov
2017-07-10 23:44         ` Evgeny Baskakov
2017-07-11 18:29           ` Jerome Glisse
2017-07-11 18:42             ` Evgeny Baskakov
2017-07-11 18:49               ` Jerome Glisse
2017-07-11 19:35                 ` Evgeny Baskakov
2017-07-13 20:16                   ` Jerome Glisse
2017-07-14  5:32                     ` Evgeny Baskakov
2017-07-14 19:43                     ` Evgeny Baskakov
2017-07-15  0:55                       ` Jerome Glisse
2017-07-15  5:04                         ` Evgeny Baskakov
2017-07-21  1:00                         ` Evgeny Baskakov
2017-07-21  1:33                           ` Jerome Glisse
2017-07-21 22:01                             ` Evgeny Baskakov
2017-07-25 22:45                             ` Evgeny Baskakov
2017-07-26 19:14                               ` Jerome Glisse
2017-05-22 16:52 ` [HMM 13/15] mm/migrate: migrate_vma() unmap page from vma while collecting pages Jérôme Glisse
2017-05-22 16:52 ` [HMM 14/15] mm/migrate: support un-addressable ZONE_DEVICE page in migration v2 Jérôme Glisse
2017-05-22 16:52 ` [HMM 15/15] mm/migrate: allow migrate_vma() to alloc new page on empty entry v2 Jérôme Glisse
2017-05-23 22:02 ` [HMM 00/15] HMM (Heterogeneous Memory Management) v22 Jerome Glisse
2017-05-23 22:05   ` Andrew Morton
2017-05-24  1:55 ` Balbir Singh
2017-05-24 17:53   ` Jerome Glisse
2017-06-01  2:04     ` Balbir Singh
2017-06-01 22:38       ` Jerome Glisse
2017-06-03  9:18         ` Balbir Singh
2017-05-24 17:20 [HMM 00/15] HMM (Heterogeneous Memory Management) v23 Jérôme Glisse
2017-05-24 17:20 ` [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4 Jérôme Glisse
2017-05-31  3:59   ` Balbir Singh
2017-06-01 22:35     ` Jerome Glisse
2017-06-07  9:02       ` Balbir Singh
2017-06-07 14:06         ` Jerome Glisse

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