d31331e2df
commit da62cb7230f0871c30dc9789071f63229158d261 upstream. I got a use-after-free report when doing some fuzz test: If ttm_bo_init() fails, the "gbo" and "gbo->bo.base" will be freed by ttm_buffer_object_destroy() in ttm_bo_init(). But then drm_gem_vram_create() and drm_gem_vram_init() will free "gbo" and "gbo->bo.base" again. BUG: KMSAN: use-after-free in drm_vma_offset_remove+0xb3/0x150 CPU: 0 PID: 24282 Comm: syz-executor.1 Tainted: G B W 5.7.0-rc4-msan #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: __dump_stack dump_stack+0x1c9/0x220 kmsan_report+0xf7/0x1e0 __msan_warning+0x58/0xa0 drm_vma_offset_remove+0xb3/0x150 drm_gem_free_mmap_offset drm_gem_object_release+0x159/0x180 drm_gem_vram_init drm_gem_vram_create+0x7c5/0x990 drm_gem_vram_fill_create_dumb drm_gem_vram_driver_dumb_create+0x238/0x590 drm_mode_create_dumb drm_mode_create_dumb_ioctl+0x41d/0x450 drm_ioctl_kernel+0x5a4/0x710 drm_ioctl+0xc6f/0x1240 vfs_ioctl ksys_ioctl __do_sys_ioctl __se_sys_ioctl+0x2e9/0x410 __x64_sys_ioctl+0x4a/0x70 do_syscall_64+0xb8/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x4689b9 Code: fd e0 fa ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 cb e0 fa ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f368fa4dc98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 000000000076bf00 RCX: 00000000004689b9 RDX: 0000000020000240 RSI: 00000000c02064b2 RDI: 0000000000000003 RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000004d17e0 R14: 00007f368fa4e6d4 R15: 000000000076bf0c Uninit was created at: kmsan_save_stack_with_flags kmsan_internal_poison_shadow+0x66/0xd0 kmsan_slab_free+0x6e/0xb0 slab_free_freelist_hook slab_free kfree+0x571/0x30a0 drm_gem_vram_destroy ttm_buffer_object_destroy+0xc8/0x130 ttm_bo_release kref_put ttm_bo_put+0x117d/0x23e0 ttm_bo_init_reserved+0x11c0/0x11d0 ttm_bo_init+0x289/0x3f0 drm_gem_vram_init drm_gem_vram_create+0x775/0x990 drm_gem_vram_fill_create_dumb drm_gem_vram_driver_dumb_create+0x238/0x590 drm_mode_create_dumb drm_mode_create_dumb_ioctl+0x41d/0x450 drm_ioctl_kernel+0x5a4/0x710 drm_ioctl+0xc6f/0x1240 vfs_ioctl ksys_ioctl __do_sys_ioctl __se_sys_ioctl+0x2e9/0x410 __x64_sys_ioctl+0x4a/0x70 do_syscall_64+0xb8/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xa9 If ttm_bo_init() fails, the "gbo" will be freed by ttm_buffer_object_destroy() in ttm_bo_init(). But then drm_gem_vram_create() and drm_gem_vram_init() will free "gbo" again. Reported-by: Hulk Robot <hulkci@huawei.com> Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com> Cc: x kaneiki <xkaneiki@gmail.com> Signed-off-by: Jia Yang <jiayang5@huawei.com> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://patchwork.freedesktop.org/patch/msgid/20200714083238.28479-2-tzimmermann@suse.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.