RSP: 002b:00000000f5d550cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000ffffffb2 RDX: 0000000020000040 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ================================================================== BUG: KASAN: use-after-free in drm_gem_object_release+0xf1/0x110 drivers/gpu/drm/drm_gem.c:849 Read of size 8 at addr ffff888089d4b890 by task syz-executor.0/28998 CPU: 0 PID: 28998 Comm: syz-executor.0 Not tainted 5.1.0-rc1 #28 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132 drm_gem_object_release+0xf1/0x110 drivers/gpu/drm/drm_gem.c:849 vkms_gem_create.part.0+0x147/0x170 drivers/gpu/drm/vkms/vkms_gem.c:115 vkms_gem_create drivers/gpu/drm/vkms/vkms_gem.c:105 [inline] vkms_dumb_create+0x11e/0x240 drivers/gpu/drm/vkms/vkms_gem.c:138 drm_mode_create_dumb+0x288/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 drm_ioctl_kernel+0x23e/0x2e0 drivers/gpu/drm/drm_ioctl.c:770 drm_ioctl+0x545/0xa50 drivers/gpu/drm/drm_ioctl.c:870 drm_compat_ioctl+0x241/0x310 drivers/gpu/drm/drm_ioc32.c:966 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline] __ia32_compat_sys_ioctl+0x197/0x620 fs/compat_ioctl.c:998 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f59869 Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f5d550cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000ffffffb2 RDX: 0000000020000040 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Allocated by task 28998: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_kmalloc mm/kasan/common.c:497 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3621 vkms_gem_create.part.0+0x5f/0x170 include/linux/slab.h:545 vkms_gem_create drivers/gpu/drm/vkms/vkms_gem.c:105 [inline] vkms_dumb_create+0x11e/0x240 drivers/gpu/drm/vkms/vkms_gem.c:138 drm_mode_create_dumb+0x288/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 drm_ioctl_kernel+0x23e/0x2e0 drivers/gpu/drm/drm_ioctl.c:770 drm_ioctl+0x545/0xa50 drivers/gpu/drm/drm_ioctl.c:870 drm_compat_ioctl+0x241/0x310 drivers/gpu/drm/drm_ioc32.c:966 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline] __ia32_compat_sys_ioctl+0x197/0x620 fs/compat_ioctl.c:998 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 Freed by task 28998: save_stack+0x45/0xd0 mm/kasan/common.c:75 set_track mm/kasan/common.c:87 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467 __cache_free mm/slab.c:3498 [inline] kfree+0xcf/0x230 mm/slab.c:3821 vkms_gem_free_object+0x89/0xb0 drivers/gpu/drm/vkms/vkms_gem.c:39 drm_gem_object_free+0x108/0x260 drivers/gpu/drm/drm_gem.c:877 kref_put include/linux/kref.h:67 [inline] drm_gem_object_put_unlocked drivers/gpu/drm/drm_gem.c:911 [inline] drm_gem_object_put_unlocked+0x129/0x170 drivers/gpu/drm/drm_gem.c:896 vkms_gem_create.part.0+0x101/0x170 drivers/gpu/drm/vkms/vkms_gem.c:113 vkms_gem_create drivers/gpu/drm/vkms/vkms_gem.c:105 [inline] vkms_dumb_create+0x11e/0x240 drivers/gpu/drm/vkms/vkms_gem.c:138 drm_mode_create_dumb+0x288/0x310 drivers/gpu/drm/drm_dumb_buffers.c:92 drm_mode_create_dumb_ioctl+0x26/0x30 drivers/gpu/drm/drm_dumb_buffers.c:98 drm_ioctl_kernel+0x23e/0x2e0 drivers/gpu/drm/drm_ioctl.c:770 drm_ioctl+0x545/0xa50 drivers/gpu/drm/drm_ioctl.c:870 drm_compat_ioctl+0x241/0x310 drivers/gpu/drm/drm_ioc32.c:966 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline] __ia32_compat_sys_ioctl+0x197/0x620 fs/compat_ioctl.c:998 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x281/0xc98 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 The buggy address belongs to the object at ffff888089d4b780 which belongs to the cache kmalloc-512 of size 512 The buggy address is located 272 bytes inside of 512-byte region [ffff888089d4b780, ffff888089d4b980) The buggy address belongs to the page: page:ffffea00022752c0 count:1 mapcount:0 mapping:ffff88812c3f0940 index:0xffff888089d4b000 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea0002913b88 ffffea00022e3f48 ffff88812c3f0940 raw: ffff888089d4b000 ffff888089d4b000 0000000100000005 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888089d4b780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888089d4b800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff888089d4b880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888089d4b900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888089d4b980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ==================================================================