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Matthew Auld cef8ce5528 drm/i915: check i915_vm_alloc_pt_stash for errors
If we are really unlucky and encounter an error during
i915_vm_alloc_pt_stash, we end up passing an empty pt/pd stash all the
way down into the low-level ppgtt alloc code, leading to explosions,
since it expects at least the required number of pt/pd for the va range.

[  211.981418] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  211.981421] #PF: supervisor read access in kernel mode
[  211.981422] #PF: error_code(0x0000) - not-present page
[  211.981424] PGD 80000008439cb067 P4D 80000008439cb067 PUD 84a37f067 PMD 0
[  211.981427] Oops: 0000 [#1] SMP PTI
[  211.981428] CPU: 1 PID: 1301 Comm: i915_selftest Tainted: G     U    I       5.9.0-rc5+ #3
[  211.981430] Hardware name:  /NUC6i7KYB, BIOS KYSKLi70.86A.0050.2017.0831.1924 08/31/2017
[  211.981521] RIP: 0010:__gen8_ppgtt_alloc+0x1ed/0x3c0 [i915]
[  211.981523] Code: c1 48 c7 c7 5d 5d fe c0 65 ff 0d ee 1d 03 3f e8 d9 91 1f e2 8b 55 c4 31 c0 48 8b 75 b8 85 d2 0f 95 c0 48 8b 1c c6 48 89 45 98 <48> 8b 03 48 8b 90 58 02 00 00 48 85 d2 0f 84 07 ea 15 00 48 81 fa
[  211.981526] RSP: 0018:ffffba2cc0eb3970 EFLAGS: 00010202
[  211.981527] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000004
[  211.981529] RDX: 0000000000000002 RSI: ffff9be998bdb8c0 RDI: ffff9be99c844300
[  211.981530] RBP: ffffba2cc0eb39d8 R08: 0000000000000640 R09: ffff9be97cdfd000
[  211.981531] R10: ffff9be97cdfd614 R11: 0000000000000000 R12: 0000000000000000
[  211.981532] R13: ffff9be98607ba20 R14: ffff9be995a0b400 R15: ffffba2cc0eb39e8
[  211.981534] FS:  00007f0f10b31000(0000) GS:ffff9be99fc40000(0000) knlGS:0000000000000000
[  211.981536] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  211.981538] CR2: 0000000000000000 CR3: 000000084d74e006 CR4: 00000000003706e0
[  211.981539] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  211.981541] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  211.981542] Call Trace:
[  211.981609]  gen8_ppgtt_alloc+0x79/0x90 [i915]
[  211.981678]  ppgtt_bind_vma+0x36/0x80 [i915]
[  211.981756]  __vma_bind+0x39/0x40 [i915]
[  211.981818]  fence_work+0x21/0x98 [i915]
[  211.981879]  fence_notify+0x8d/0x128 [i915]
[  211.981939]  __i915_sw_fence_complete+0x62/0x240 [i915]
[  211.982018]  i915_vma_pin_ww+0x1ee/0x9c0 [i915]

Fixes: cd0452aa2a ("drm/i915: Preallocate stashes for vma page-directories")
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200921160844.73186-1-matthew.auld@intel.com
(cherry picked from commit 1604cb2aa7)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
2020-09-30 14:24:35 -04:00
Documentation drm-misc-next for 5.10: 2020-09-23 09:52:24 +10:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch ARM: SoC fixes 2020-09-13 14:54:40 -07:00
block - Fix a regression in bdev partition locking (Christoph) 2020-09-11 11:55:28 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2020-08-30 15:53:44 -07:00
drivers drm/i915: check i915_vm_alloc_pt_stash for errors 2020-09-30 14:24:35 -04:00
fs Driver core fixes for 5.9-rc5 2020-09-13 09:02:59 -07:00
include drm-misc-next for 5.10: 2020-09-23 09:52:24 +10:00
init init: fix error check in clean_path() 2020-09-04 09:16:58 -07:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel Linux 5.9-rc5 2020-09-14 17:19:11 +02:00
lib Merge drm/drm-next into drm-misc-next 2020-09-14 18:11:40 +02:00
mm xen: branch for v5.9-rc4 2020-09-06 09:59:27 -07:00
net NFS client bugfixes for Linux 5.9 2020-09-09 11:14:20 -07:00
samples Merge branch 'for-5.10-drm-sg-fix' of https://github.com/mszyprow/linux into drm-next 2020-09-17 16:07:11 +10:00
scripts Char / Misc driver fixes for 5.9-rc5 2020-09-13 08:52:21 -07:00
security treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sound sound fixes for 5.9-rc4 2020-09-04 12:05:25 -07:00
tools KVM/arm64 fixes for Linux 5.9, take #1 2020-09-11 13:12:11 -04:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt KVM: fix memory leak in kvm_io_bus_unregister_dev() 2020-09-11 13:15:11 -04:00
.clang-format clang-format: Update with the latest for_each macro list 2020-09-01 12:53:42 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: Add ZSTD-compressed files 2020-07-31 11:50:49 +02:00
.mailmap mailmap, MAINTAINERS: move to tycho.pizza 2020-09-08 11:29:57 -07:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS CREDITS: Replace HTTP links with HTTPS ones 2020-07-23 14:53:58 -06:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: make linux-aspeed list remarks consistent 2020-09-17 13:39:44 +02:00
Makefile Linux 5.9-rc5 2020-09-13 16:06:00 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.