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Chris Wilson 178536b829 drm/i915: Use the active reference on the vma while capturing
During error capture, we need to take a reference to the vma from before
the reset in order to catpure the contents of the vma later. Currently
we are using both an active reference and a kref, but due to nature of
the i915_vma reference handling, that kref is on the vma->obj and not
the vma itself. This means the vma may be destroyed as soon as it is
idle, that is in between the i915_active_release(&vma->active) and the
i915_vma_put(vma):

<3> [197.866181] BUG: KASAN: use-after-free in intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<3> [197.866339] Read of size 8 at addr ffff8881258cb800 by task gem_exec_captur/1041
<3> [197.866467]
<4> [197.866512] CPU: 2 PID: 1041 Comm: gem_exec_captur Not tainted 5.9.0-g5e4234f97efba-kasan_200+ #1
<4> [197.866521] Hardware name: Intel Corp. Broxton P/Apollolake RVP1A, BIOS APLKRVPA.X64.0150.B11.1608081044 08/08/2016
<4> [197.866530] Call Trace:
<4> [197.866549]  dump_stack+0x99/0xd0
<4> [197.866760]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.866783]  print_address_description.constprop.8+0x3e/0x60
<4> [197.866797]  ? kmsg_dump_rewind_nolock+0xd4/0xd4
<4> [197.866819]  ? lockdep_hardirqs_off+0xd4/0x120
<4> [197.867037]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867249]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867270]  kasan_report.cold.10+0x1f/0x37
<4> [197.867492]  ? intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867710]  intel_engine_coredump_add_vma+0x36c/0x4a0 [i915]
<4> [197.867949]  i915_gpu_coredump.part.29+0x150/0x7b0 [i915]
<4> [197.868186]  i915_capture_error_state+0x5e/0xc0 [i915]
<4> [197.868396]  intel_gt_handle_error+0x6eb/0xa20 [i915]
<4> [197.868624]  ? intel_gt_reset_global+0x370/0x370 [i915]
<4> [197.868644]  ? check_flags+0x50/0x50
<4> [197.868662]  ? __lock_acquire+0xd59/0x6b00
<4> [197.868678]  ? register_lock_class+0x1ad0/0x1ad0
<4> [197.868944]  i915_wedged_set+0xcf/0x1b0 [i915]
<4> [197.869147]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869371]  ? i915_wedged_get+0x90/0x90 [i915]
<4> [197.869398]  simple_attr_write+0x153/0x1c0
<4> [197.869428]  full_proxy_write+0xee/0x180
<4> [197.869442]  ? __sb_start_write+0x1f3/0x310
<4> [197.869465]  vfs_write+0x1a3/0x640
<4> [197.869492]  ksys_write+0xec/0x1c0
<4> [197.869507]  ? __ia32_sys_read+0xa0/0xa0
<4> [197.869525]  ? lockdep_hardirqs_on_prepare+0x32b/0x4e0
<4> [197.869541]  ? syscall_enter_from_user_mode+0x1c/0x50
<4> [197.869566]  do_syscall_64+0x33/0x80
<4> [197.869579]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<4> [197.869590] RIP: 0033:0x7fd8b7aee281
<4> [197.869604] Code: c3 0f 1f 84 00 00 00 00 00 48 8b 05 59 8d 20 00 c3 0f 1f 84 00 00 00 00 00 8b 05 8a d1 20 00 85 c0 75 16 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 57 f3 c3 0f 1f 44 00 00 41 54 55 49 89 d4 53
<4> [197.869613] RSP: 002b:00007ffea3b72008 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
<4> [197.869625] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd8b7aee281
<4> [197.869633] RDX: 0000000000000002 RSI: 00007fd8b81a82e7 RDI: 000000000000000d
<4> [197.869641] RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000034
<4> [197.869650] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8b81a82e7
<4> [197.869658] R13: 000000000000000d R14: 0000000000000000 R15: 0000000000000000
<3> [197.869707]
<3> [197.869757] Allocated by task 1041:
<4> [197.869833]  kasan_save_stack+0x19/0x40
<4> [197.869843]  __kasan_kmalloc.constprop.5+0xc1/0xd0
<4> [197.869853]  kmem_cache_alloc+0x106/0x8e0
<4> [197.870059]  i915_vma_instance+0x212/0x1930 [i915]
<4> [197.870270]  eb_lookup_vmas+0xe06/0x1d10 [i915]
<4> [197.870475]  i915_gem_do_execbuffer+0x131d/0x4080 [i915]
<4> [197.870682]  i915_gem_execbuffer2_ioctl+0x103/0x5d0 [i915]
<4> [197.870701]  drm_ioctl_kernel+0x1d2/0x270
<4> [197.870710]  drm_ioctl+0x40d/0x85c
<4> [197.870721]  __x64_sys_ioctl+0x10d/0x170
<4> [197.870731]  do_syscall_64+0x33/0x80
<4> [197.870740]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
<3> [197.870748]
<3> [197.870798] Freed by task 22:
<4> [197.870865]  kasan_save_stack+0x19/0x40
<4> [197.870875]  kasan_set_track+0x1c/0x30
<4> [197.870884]  kasan_set_free_info+0x1b/0x30
<4> [197.870894]  __kasan_slab_free+0x111/0x160
<4> [197.870903]  kmem_cache_free+0xcd/0x710
<4> [197.871109]  i915_vma_parked+0x618/0x800 [i915]
<4> [197.871307]  __gt_park+0xdb/0x1e0 [i915]
<4> [197.871501]  ____intel_wakeref_put_last+0xb1/0x190 [i915]
<4> [197.871516]  process_one_work+0x8dc/0x15d0
<4> [197.871525]  worker_thread+0x82/0xb30
<4> [197.871535]  kthread+0x36d/0x440
<4> [197.871545]  ret_from_fork+0x22/0x30
<3> [197.871553]
<3> [197.871602] The buggy address belongs to the object at ffff8881258cb740
 which belongs to the cache i915_vma of size 968

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2553
Fixes: 2850748ef8 ("drm/i915: Pull i915_vma_pin under the vm->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201016092527.29039-1-chris@chris-wilson.co.uk
2020-10-16 15:10:36 +01:00
arch powerpc fixes for 5.9 #3 2020-08-23 11:37:23 -07:00
block block-5.9-2020-08-14 2020-08-15 20:36:42 -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 2020-08-14 13:09:15 -07:00
Documentation drm-misc-next for 5.10: 2020-08-28 12:38:06 +10:00
drivers drm/i915: Use the active reference on the vma while capturing 2020-10-16 15:10:36 +01:00
fs Merge branch 'work.epoll' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-22 17:11:38 -07:00
include UAPI Changes: 2020-08-28 14:09:31 +10:00
init OpenRISC updates for 5.9 2020-08-14 14:04:53 -07:00
ipc ipc/shm.c: remove the superfluous break 2020-08-12 10:58:02 -07:00
kernel drm-misc-next for 5.10: 2020-08-28 12:38:06 +10:00
lib lib/string.c: Use freestanding environment 2020-08-19 11:23:45 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm, page_alloc: fix core hung in free_pcppages_bulk() 2020-08-21 09:52:53 -07:00
net net: nexthop: don't allow empty NHA_GROUP 2020-08-22 12:39:55 -07:00
samples Kbuild updates for v5.9 2020-08-09 14:10:26 -07:00
scripts kconfig: qconf: replace deprecated QString::sprintf() with QTextStream 2020-08-21 10:23:38 +09:00
security Merge branch 'akpm' (patches from Andrew) 2020-08-12 11:24:12 -07:00
sound sound fixes for 5.9-rc2 2020-08-21 10:07:54 -07:00
tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2020-08-23 10:52:33 -07:00
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 * PAE and PKU bugfixes for x86 2020-08-22 10:03:05 -07:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +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 Merge branch 'akpm' (patches from Andrew) 2020-08-21 14:44:48 -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 drm-misc-next for 5.10: 2020-08-28 12:38:06 +10:00
Makefile Linux 5.9-rc2 2020-08-23 14:08:43 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.