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Chris Wilson bea6e987c1 drm/i915: Hold rcu_read_lock when iterating over the radixtree (objects)
Kasan spotted

    [IGT] gem_tiled_pread_pwrite: exiting, ret=0
    ==================================================================
    BUG: KASAN: use-after-free in __i915_gem_object_reset_page_iter+0x15c/0x170 [i915]
    Read of size 8 at addr ffff8801359da310 by task kworker/3:2/182

    CPU: 3 PID: 182 Comm: kworker/3:2 Tainted: G     U          4.14.0-rc6-CI-Custom_3340+ #1
    Hardware name: Intel Corp. Geminilake/GLK RVP1 DDR4 (05), BIOS GELKRVPA.X64.0062.B30.1708222146 08/22/2017
    Workqueue: events __i915_gem_free_work [i915]
    Call Trace:
     dump_stack+0x68/0xa0
     print_address_description+0x78/0x290
     ? __i915_gem_object_reset_page_iter+0x15c/0x170 [i915]
     kasan_report+0x23d/0x350
     __asan_report_load8_noabort+0x19/0x20
     __i915_gem_object_reset_page_iter+0x15c/0x170 [i915]
     ? i915_gem_object_truncate+0x100/0x100 [i915]
     ? lock_acquire+0x380/0x380
     __i915_gem_object_put_pages+0x30d/0x530 [i915]
     __i915_gem_free_objects+0x551/0xbd0 [i915]
     ? lock_acquire+0x13e/0x380
     __i915_gem_free_work+0x4e/0x70 [i915]
     process_one_work+0x6f6/0x1590
     ? pwq_dec_nr_in_flight+0x2b0/0x2b0
     worker_thread+0xe6/0xe90
     ? pci_mmcfg_check_reserved+0x110/0x110
     kthread+0x309/0x410
     ? process_one_work+0x1590/0x1590
     ? kthread_create_on_node+0xb0/0xb0
     ret_from_fork+0x27/0x40

    Allocated by task 1801:
     save_stack_trace+0x1b/0x20
     kasan_kmalloc+0xee/0x190
     kasan_slab_alloc+0x12/0x20
     kmem_cache_alloc+0xdc/0x2e0
     radix_tree_node_alloc.constprop.12+0x48/0x330
     __radix_tree_create+0x274/0x480
     __radix_tree_insert+0xa2/0x610
     i915_gem_object_get_sg+0x224/0x670 [i915]
     i915_gem_object_get_page+0xb5/0x1c0 [i915]
     i915_gem_pread_ioctl+0x822/0xf60 [i915]
     drm_ioctl_kernel+0x13f/0x1c0
     drm_ioctl+0x6cf/0x980
     do_vfs_ioctl+0x184/0xf30
     SyS_ioctl+0x41/0x70
     entry_SYSCALL_64_fastpath+0x1c/0xb1

    Freed by task 37:
     save_stack_trace+0x1b/0x20
     kasan_slab_free+0xaf/0x190
     kmem_cache_free+0xbf/0x340
     radix_tree_node_rcu_free+0x79/0x90
     rcu_process_callbacks+0x46d/0xf40
     __do_softirq+0x21c/0x8d3

    The buggy address belongs to the object at ffff8801359da0f0
    which belongs to the cache radix_tree_node of size 576
    The buggy address is located 544 bytes inside of
    576-byte region [ffff8801359da0f0, ffff8801359da330)
    The buggy address belongs to the page:
    page:ffffea0004d67600 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
    flags: 0x8000000000008100(slab|head)
    raw: 8000000000008100 0000000000000000 0000000000000000 0000000100110011
    raw: ffffea0004b52920 ffffea0004b38020 ffff88015b416a80 0000000000000000
    page dumped because: kasan: bad access detected

    Memory state around the buggy address:
     ffff8801359da200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
     ffff8801359da280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
    >ffff8801359da300: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc
			     ^
     ffff8801359da380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
     ffff8801359da400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
    ==================================================================
    Disabling lock debugging due to kernel taint

which looks like the slab containing the radixtree iter was freed as we
traversed the tree, taking the rcu read lock across the loop should
prevent that (deferring all the frees until the end).

Reported-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
Fixes: 96d7763452 ("drm/i915: Use a radixtree for random access to the object's backing storage")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171026130032.10677-1-chris@chris-wilson.co.uk
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
2017-10-27 12:38:45 +01:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 13:55:32 -07:00
block block: fix a crash caused by wrong API 2017-09-25 08:56:05 -06:00
certs modsign: add markers to endif-statements in certs/Makefile 2017-07-14 11:01:37 +10:00
crypto crypto: af_alg - update correct dst SGL entry 2017-09-20 17:42:42 +08:00
Documentation dt-bindings: display: sun4i: Add binding for A31 HDMI controller 2017-10-11 09:53:25 +02:00
drivers drm/i915: Hold rcu_read_lock when iterating over the radixtree (objects) 2017-10-27 12:38:45 +01:00
firmware firmware: Restore support for built-in firmware 2017-09-16 10:58:48 -07:00
fs Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:10:02 -07:00
include Merge drm-upstream/drm-next into drm-intel-next-queued 2017-10-18 12:37:31 +03:00
init Merge branch 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:54:01 -07:00
ipc fix a typo in put_compat_shm_info() 2017-09-25 20:41:46 -04:00
kernel Merge branch 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-10-01 12:34:42 -07:00
lib Merge drm-upstream/drm-next into drm-intel-next-queued 2017-09-28 15:56:49 +03:00
mm Merge drm-upstream/drm-next into drm-intel-next-queued 2017-10-18 12:37:31 +03:00
net Revert "Bluetooth: Add option for disabling legacy ioctl interfaces" 2017-09-28 13:20:32 -07:00
samples media updates for v4.14-rc1 2017-09-07 12:53:14 -07:00
scripts Merge airlied/drm-next into drm-misc-next 2017-10-03 11:09:16 +02:00
security Merge commit 'keys-fixes-20170927' into fixes-v4.14-rc3 2017-09-28 09:11:28 +10:00
sound vfs: constify path argument to kernel_read_file_from_path 2017-09-14 20:18:45 -07:00
tools 2nd batch of v4.15 features: 2017-10-12 10:20:03 +10:00
usr ramfs: clarify help text that compression applies to ramfs as well as legacy ramdisk. 2017-07-06 16:24:30 -07:00
virt Revert "KVM: Don't accept obviously wrong gsi values via KVM_IRQFD" 2017-09-19 08:37:17 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS MAINTAINERS: Add dri-devel as a mailing list for anything fbdev 2017-10-03 11:23:42 +02:00
Makefile Linux 4.14-rc3 2017-10-01 14:54:54 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

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.