929eec99f5
We have to avoid chasing after a userspace race! <3>[ 473.114328] BUG: KASAN: use-after-free in i915_gem_create+0x1d2/0x1f0 [i915] <3>[ 473.114389] Read of size 8 at addr ffff88815bf1d840 by task gem_flink_race/1541 <4>[ 473.114464] CPU: 1 PID: 1541 Comm: gem_flink_race Tainted: G U 5.1.0-rc4-g7d07e025e786-kasan_88+ #1 <4>[ 473.114469] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./J4205-ITX, BIOS P1.10 09/29/2016 <4>[ 473.114474] Call Trace: <4>[ 473.114488] dump_stack+0x7c/0xbb <4>[ 473.114612] ? i915_gem_create+0x1d2/0x1f0 [i915] <4>[ 473.114621] print_address_description+0x65/0x270 <4>[ 473.114728] ? i915_gem_create+0x1d2/0x1f0 [i915] <4>[ 473.114839] ? i915_gem_create+0x1d2/0x1f0 [i915] <4>[ 473.114848] kasan_report+0x149/0x18d <4>[ 473.114962] ? i915_gem_create+0x1d2/0x1f0 [i915] <4>[ 473.115069] i915_gem_create+0x1d2/0x1f0 [i915] <4>[ 473.115176] ? i915_gem_object_create.part.28+0x4b0/0x4b0 [i915] <4>[ 473.115289] ? i915_gem_dumb_create+0x1a0/0x1a0 [i915] <4>[ 473.115297] drm_ioctl_kernel+0x192/0x260 <4>[ 473.115306] ? drm_ioctl_permit+0x280/0x280 <4>[ 473.115326] drm_ioctl+0x67c/0x960 <4>[ 473.115438] ? i915_gem_dumb_create+0x1a0/0x1a0 [i915] <4>[ 473.115448] ? drm_getstats+0x20/0x20 <4>[ 473.115459] ? __lock_acquire+0xa66/0x3fe0 <4>[ 473.115474] ? _raw_spin_unlock_irqrestore+0x39/0x60 <4>[ 473.115485] ? debug_object_active_state+0x2ea/0x4e0 <4>[ 473.115496] ? debug_show_all_locks+0x2d0/0x2d0 <4>[ 473.115513] do_vfs_ioctl+0x18d/0xfa0 <4>[ 473.115522] ? check_flags.part.27+0x440/0x440 <4>[ 473.115532] ? ioctl_preallocate+0x1a0/0x1a0 <4>[ 473.115547] ? __fget+0x2ac/0x410 <4>[ 473.115561] ? __ia32_sys_dup3+0xb0/0xb0 <4>[ 473.115569] ? rwlock_bug.part.0+0x90/0x90 <4>[ 473.115590] ksys_ioctl+0x35/0x70 <4>[ 473.115597] ? lockdep_hardirqs_off+0x1cb/0x2b0 <4>[ 473.115608] __x64_sys_ioctl+0x6a/0xb0 <4>[ 473.115614] ? lockdep_hardirqs_on+0x342/0x590 <4>[ 473.115623] do_syscall_64+0x97/0x400 <4>[ 473.115633] entry_SYSCALL_64_after_hwframe+0x49/0xbe <4>[ 473.115641] RIP: 0033:0x7fce590d55d7 <4>[ 473.115649] Code: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48 <4>[ 473.115655] RSP: 002b:00007fce4d525ba8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 <4>[ 473.115662] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fce590d55d7 <4>[ 473.115667] RDX: 00007fce4d525c10 RSI: 00000000c010645b RDI: 0000000000000007 <4>[ 473.115672] RBP: 00007fce4d525c10 R08: 00007fce4d526700 R09: 00007fce4d526700 <4>[ 473.115677] R10: 0000000000000054 R11: 0000000000000246 R12: 00000000c010645b <4>[ 473.115682] R13: 0000000000000007 R14: 0000000000000000 R15: 00007ffe0e4a7450 <3>[ 473.115731] Allocated by task 1541: <4>[ 473.115766] kmem_cache_alloc+0xce/0x290 <4>[ 473.115895] i915_gem_object_create.part.28+0x1c/0x4b0 [i915] <4>[ 473.116000] i915_gem_create+0xe3/0x1f0 [i915] <4>[ 473.116008] drm_ioctl_kernel+0x192/0x260 <4>[ 473.116013] drm_ioctl+0x67c/0x960 <4>[ 473.116020] do_vfs_ioctl+0x18d/0xfa0 <4>[ 473.116026] ksys_ioctl+0x35/0x70 <4>[ 473.116032] __x64_sys_ioctl+0x6a/0xb0 <4>[ 473.116038] do_syscall_64+0x97/0x400 <4>[ 473.116044] entry_SYSCALL_64_after_hwframe+0x49/0xbe <3>[ 473.116071] Freed by task 1542: <4>[ 473.116101] kmem_cache_free+0xb7/0x2f0 <4>[ 473.116205] __i915_gem_free_objects+0x7d4/0xe10 [i915] <4>[ 473.116311] i915_gem_create_ioctl+0xaa/0xd0 [i915] <4>[ 473.116318] drm_ioctl_kernel+0x192/0x260 <4>[ 473.116323] drm_ioctl+0x67c/0x960 <4>[ 473.116330] do_vfs_ioctl+0x18d/0xfa0 <4>[ 473.116335] ksys_ioctl+0x35/0x70 <4>[ 473.116341] __x64_sys_ioctl+0x6a/0xb0 <4>[ 473.116347] do_syscall_64+0x97/0x400 <4>[ 473.116354] entry_SYSCALL_64_after_hwframe+0x49/0xbe Testcase: igt/gem_flink_race/flink_close Fixes: e163484afa8d ("drm/i915: Update size upon return from GEM_CREATE") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Michał Winiarski <michal.winiarski@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190417132507.27133-1-chris@chris-wilson.co.uk (cherry picked from commit 99534023490686ce4453c45e5cb813535b9bff95) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
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.